The review, led by Simon De Jaegher of the University of Siena and The BioArte Ltd., together with colleagues in Italy and Malta, takes an unusual approach. Instead of cataloguing fermentation platforms, it examines the entire experimental workflow as an interconnected system, from model selection and inoculum preparation to culture media, environmental control and community stabilization. The authors contend that biological relevance is not an intrinsic property of any model type but a question-dependent property: a system may be perfectly suited to one experimental question while being useless for another.

At the simplest end of the spectrum sit batch fermentation systems, typically set up in well plates, test tubes or bioreactors. These closed environments are prized for rapid, cost-effective screening of acute microbial responses, such as how a dietary compound is metabolized or how bacteria adhere to a mucin-coated surface. But their biological relevance decays quickly. Without continuous nutrient supply or waste removal, incubation is usually limited to 24 to 48 hours before nutrient exhaustion and toxic metabolite accumulation disrupt the microbial balance. The result is ecological drift, a progressive culture-induced deviation from the original community that favours fast-growing, metabolically flexible taxa while disadvantaging oxygen-sensitive or nutritionally fastidious organisms.

Fed-batch systems offer an intermediate strategy, periodically supplying fresh medium to prolong microbial activity without implementing continuous flow. But the gold standard for long-term experiments is the continuous culture system, in which fresh medium is supplied while an equivalent volume of culture is removed, maintaining approximately constant conditions. A chemostat, a specific type of continuous culture, controls microbial growth through the dilution rate and the availability of a growth-limiting nutrient. Multistage platforms go further, connecting successive vessels whose pH, oxygen, temperature and transit time are individually configured to mimic different regions of the digestive tract. The Reading Model, developed in 1988, used three consecutive vessels to reproduce the proximal, transverse and distal colon, while the TNO gastro-intestinal model added four compartments simulating the stomach, duodenum, jejunum and ileum. The SHIME system, or Simulator of the Human Intestinal Microbial Ecosystem, pumps pancreatic and bile juices into specific vessels at precise intervals, representing the most advanced fermentation modeling to date.

Yet even the most sophisticated bioreactor is only as good as its starting material. The review devotes considerable attention to the microbial inoculum, the community introduced into the reactor to initiate fermentation. When human feces are used, approval from a research ethics committee is mandatory, and donors should not have received antibiotics for at least three months or prebiotics and probiotics for at least one month prior to collection. Sample handling is one of the greatest sources of experimental bias because it directly influences the survival of oxygen-sensitive microorganisms. Best practice calls for collection under sterile conditions, transport at 4 degrees Celsius, and processing in an anaerobic cabinet under an atmosphere of approximately 85 percent nitrogen, 10 percent carbon dioxide and 5 percent hydrogen.

The format of the inoculum also matters profoundly. Liquid fecal suspensions, typically homogenized with culture medium or phosphate-buffered saline at a ratio of 5 to 10 percent weight per volume, are prone to rapid compositional shifts and the elimination of less competitive bacteria. Immobilized inocula, in which microorganisms are entrapped in gel beads composed of gellan gum, xanthan gum and sodium citrate, tend to better preserve low-abundance and fastidious microorganisms over time. Inoculum density is equally critical: low ratios of 0.1 to 1 percent allow greater microbial expansion, while higher ratios above 10 percent are used when the biomass primarily provides enzymatic capacity rather than supporting extensive growth. Intermediate concentrations around 3 percent have been shown to support representative growth conditions of the human intestinal microbiota.

Culture media are another central determinant of biological relevance, yet the review highlights a striking lack of standardization. Of ten different media used for gut microbiota modeling, only seven compounds are found in more than half of them. Two distinct trophic approaches exist: oligotrophic media, inoculated with a high concentration of fecal slurry and supplemented with minimal nutrients, aim to reflect the gut under normal or calorie-restricted diets, while eutrophic media, inoculated with around 1 percent fecal slurry into a basal medium enriched with peptone, yeast extract and bile salts, simulate the nutrient-rich environment associated with high-fat and high-protein diets. Small variations in medium composition can profoundly alter community structure and metabolic output. Low-carbohydrate media significantly reduce microbial biodiversity and short-chain fatty acid production, whereas commercial Schaedler broth supplemented with 5 percent sheep blood helps preserve both high biodiversity and metabolic activity.

Once fermentation begins, maintaining environmental conditions that preserve microbial ecology becomes equally critical. Temperature is typically held at 37 degrees Celsius, pH within a near-neutral range of approximately 6.8 to 7.2 to reflect colonic conditions, and anaerobiosis is maintained using gas mixtures of nitrogen, carbon dioxide and hydrogen. pH is one of the most influential regulators of gut microbial ecology, directly affecting enzymatic activity, substrate utilization and interspecies competition. Substrate fermentation naturally lowers pH, which can boost butyrate production and promote butyrate-producing bacteria while inhibiting certain taxa such as Bacteroides species. For continuous fermenters, monitoring extends to hydraulic retention time and flow rate, enabling a more physiologically relevant simulation of colonic conditions. Community stability is typically evaluated over periods exceeding one week by combining 16S rRNA gene amplicon sequencing with metabolic activity measurements, using ecological distance metrics such as Bray-Curtis dissimilarity. The production of short-chain fatty acids serves as a rapid indicator of metabolic function, with acetate, propionate and butyrate typically found in the colon at an approximate molar ratio of 60:20:20.

The review also examines how validated models can be used to study microbiota modulation through dietary, probiotic and pharmacological interventions. Food samples are first subjected to a standardized simulation of upper gastrointestinal digestion using established protocols such as the INFOGEST method, with the non-digested solid residue and a defined proportion of the intestinal soluble fraction used as the fermentation substrate. Studies consistently demonstrate that microbial responses are highly dependent on baseline composition: following in vitro fermentation of rye, butyrate production was higher only in microbiota enriched in Prevotella and Subdoligranulum, whereas Bacteroides-dominated communities showed little increase. In the pharmacological realm, a high-throughput metaproteomics-based screening platform called RapidAIM found that 35 out of 39 non-antibiotic compounds, including berberine and ibuprofen, modulated the microbial proteome, metabolic function and biomass to varying degrees among different individual microbiotas. Some compounds selectively affected specific microbial taxa without impacting their relative abundance, suggesting that functional modulation can occur independently of compositional shifts.

Looking ahead, the authors argue that the principal requirement for generating biologically relevant and reproducible in vitro gut microbiota models is rigorous methodological standardization rather than increasing technological complexity alone. Emerging host-microbe co-culture systems, including organoids and gut-on-chip platforms that integrate oxygen gradients, microbial-epithelial co-culture and mechanical stimulation approximating intestinal peristalsis, are expected to expand physiological relevance and translational applicability. But the review cautions that increasing host complexity does not necessarily increase microbial ecological fidelity, and the appropriate balance between these dimensions depends on the biological question being addressed. Ultimately, future progress will depend not only on technological innovation but also on the establishment of consensus methodologies and reporting standards that enhance reproducibility and comparability across laboratories, bridging the gap between mechanistic microbiome research and personalized interventions for human health.

Subject of Research: in vitro gut microbiota models

Article Title: Building biologically relevant in vitro models of the human gut microbiota: methodological considerations, current challenges, and future perspectives

Article References: De Jaegher, S., Podrini, C., D’Aguanno, M., Santoro, F., & Biazzo, M. (2026). Building biologically relevant in vitro models of the human gut microbiota: methodological considerations, current challenges, and future perspectives. Frontiers in Microbiology, 17, Article 1949973. https://doi.org/10.3389/fmicb.2026.1949973

Image Credits: AI Generated

DOI: 10.3389/fmicb.2026.1949973

Keywords: gut microbiota, in vitro models, fermentation, chemostat, SHIME, inoculum, culture media, ecological drift, short-chain fatty acids, prebiotics, probiotics, gut-on-chip

The distribution of professions within the sample was notably balanced. Physicians, nurses, and pharmacists each contributed 78 participants, or 24.4 percent apiece, while dietitians accounted for 86 participants, or 26.9 percent. This near-even split is a methodological strength, because it allowed the investigators to compare awareness scores across four groups with broadly comparable numbers, reducing the risk that an overrepresented profession would dominate the pooled statistics. At the same time, each subgroup remains modest in size, which means the confidence intervals around group means are wide and smaller differences between professions might not have been detected.

The instrument at the heart of the study, the Microbiota Awareness Scale, is a validated questionnaire yielding scores between 18 and 100, with higher values reflecting greater awareness. The overall mean of 77.00, with a standard deviation of 8.5, indicates that respondents generally answered a large share of awareness items correctly, but the authors are careful to note that no validated cut-off exists for the scale. In other words, there is no agreed threshold above which a person can be labeled knowledgeable and below which they are deemed uninformed. This absence of a benchmark is why the researchers frame their conclusions in relative terms, emphasizing differences between professional groups rather than absolute judgments about whether any group is adequately informed.

The statistical approach reflected the nature of the data. Because awareness scores were not normally distributed, the team used the Kruskal-Wallis test, a non-parametric method for comparing more than two independent groups, and followed it with post-hoc analyses to identify which pairs of professions differed. The result was highly significant, with a p value below 0.001, and the post-hoc comparisons showed that dietitians outperformed every other group. Dietitians averaged 83.39 points, pharmacists 77.89, nurses 73.66, and physicians 72.42. The roughly eleven-point spread between the highest and lowest groups is substantial relative to the scale’s standard deviation, suggesting a genuine difference in familiarity with microbiota concepts rather than statistical noise.

That dietitians lead is perhaps unsurprising given their training. Nutrition and dietetics curricula typically include extensive coursework on the gastrointestinal tract, dietary fibers, fermented foods, and the role of the gut microbiota in health and disease, whereas medical and nursing programs often cover these topics more briefly, and pharmacy education emphasizes drug-related microbiology over nutritional ecology. Pharmacists’ intermediate position may reflect their exposure to probiotic products in practice, since these are sold over the counter in pharmacies and are a frequent subject of customer questions. The finding that physicians scored lowest, at 72.42, is noteworthy given their authority in clinical decision-making, and it echoes a recurring theme in the literature: foundational microbiota science has entered curricula more slowly than it has entered the marketplace.

The knowledge items themselves yielded encouraging but incomplete results. About 76.9 percent of participants correctly defined probiotics, and 71.3 percent correctly defined prebiotics. These figures imply that roughly one in four respondents could not accurately define probiotics and nearly three in ten could not define prebiotics, despite the questions being directed at professionals who may be asked about these products by patients or customers. The distinction matters in practice. Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, whereas prebiotics are substrates that are selectively utilized by host microorganisms, conferring a health benefit. Confusing the two, or assuming that any fermented food or supplement qualifies, can lead to advice that does not match the underlying evidence.

Attitudes, by contrast, were almost uniformly positive. More than 95 percent of respondents viewed both probiotics and prebiotics as beneficial for health. Such enthusiasm is consistent with the broad scientific consensus that these interventions can help in specific contexts, but it also raises the question of whether favorable attitudes are grounded in detailed knowledge of which strains, doses, and indications are supported by evidence. Probiotic effects are widely understood to be strain-specific and condition-specific; a preparation shown to help with antibiotic-associated diarrhea, for example, cannot be assumed to help with irritable bowel syndrome or atopic dermatitis. A professional who believes probiotics are generally good may still struggle to guide a patient toward the right product for a particular problem, or to recognize when evidence is absent.

The most striking result of the survey is the divergence between recommendation behavior and personal practice. Nearly three quarters of respondents, 72.8 percent, said they recommend probiotic products to others, yet only 23.4 percent reported consuming them regularly themselves. The authors are careful to distinguish these two behaviors, noting that professional recommendation and personal consumption are distinct constructs. A clinician may recommend a product because they judge it appropriate for a patient’s condition while personally seeing no reason to take it, or they may hesitate to consume supplements themselves while still viewing them favorably for specific indications. Nevertheless, the size of the gap, nearly fifty percentage points, invites reflection on how confidence in a product’s value for others coexists with limited personal use.

Several explanations are plausible. Professionals may reserve recommendations for situations where they perceive a clear indication, while personal consumption requires an ongoing perceived benefit for oneself. Cost is another consideration; high-quality probiotic products can be expensive, and regular use represents a recurring expense that many may deem unnecessary in the absence of a specific health concern. Some respondents may also hold a implicit distinction between therapeutic use, which they endorse professionally, and preventive or wellness use, which they regard with more skepticism for themselves. The survey design cannot disentangle these motivations, but the pattern aligns with the knowledge-attitude-practice framework that the authors invoke, in which knowledge and favorable attitudes do not automatically translate into corresponding behavior.

This framework, known in health-services research as the KAP model, posits a progression from awareness to attitude to practice, and it underlies many educational interventions. The present study illustrates a classic KAP gap: attitudes were overwhelmingly positive, knowledge was moderate, and practice lagged behind both. The authors argue that this gap highlights the potential importance of structured, evidence-based educational interventions, and the phrasing is deliberate. Education that merely promotes enthusiasm for probiotics would likely widen the attitude-practice divide without improving the quality of advice; what is needed is training that equips professionals to match products to indications, interpret strain-specific evidence, and communicate uncertainty honestly to patients.

The cross-sectional design imposes important limits on interpretation. Because awareness, attitudes, and practices were measured at a single point in time, no causal claims can be made about whether greater awareness leads to better recommendation behavior or more consistent personal use. It is equally possible that professionals who recommend probiotics frequently become more aware of microbiota concepts through practice, or that unmeasured factors such as workplace setting, years of experience, or personal health history shape both awareness and behavior. The authors explicitly call for longitudinal research to address these questions, and such studies could follow professionals through their training and early careers to see how knowledge and practice evolve together.

The study’s provenance also merits mention. The research was conducted by a team at Sivas Cumhuriyet University in Turkey, based in the Department of Nutrition and Dietetics within the Faculty of Health Sciences, and received no external funding, which reduces concerns about commercial influence. Ethical approval was granted by the university’s Non-Interventional Clinical Research Ethics Committee, and all participants provided informed consent. The article is published open access in BMC Medical Education under a Creative Commons license, and the version shared in September 2026 is an accepted manuscript that will be replaced by the final Version of Record after further edits. The survey received approval number 2023-03/43, indicating that planning began well before publication, a reminder that the products and evidence base professionals encounter today may have evolved since the questionnaire was designed.

For readers weighing the practical implications, the study’s message is less about the merits of any particular probiotic product and more about the infrastructure of professional knowledge. When a substantial minority of health professionals cannot define prebiotics, and when recommendation behavior far outpaces personal familiarity, the market for these products is being shaped by advice that rests on uneven foundations. Strengthening that foundation, through curriculum reform, continuing education, and access to strain-specific evidence summaries, would serve both professionals and the patients who trust their guidance. The Turkish survey offers a snapshot of where that foundation currently stands, and its call for longitudinal follow-up provides a clear agenda for the next phase of research.

Subject of Research: Healthcare professionals' knowledge, attitudes, and practices regarding microbiota, probiotics, and prebiotics

Article Title: Microbiota, probiotics, and prebiotics: a cross-sectional survey of healthcare professionals’ knowledge, attitudes, and practices

Article References: Tekin, T., Baglam, N., & Dincer, E. (2026). Microbiota, probiotics, and prebiotics: a cross-sectional survey of healthcare professionals’ knowledge, attitudes, and practices. BMC Medical Education. https://doi.org/10.1186/s12909-026-10425-1

Image Credits: AI Generated

DOI: 10.1186/s12909-026-10425-1

Keywords: microbiota, probiotics, prebiotics, healthcare professionals, survey, medical education, knowledge-attitude-practice gap, dietitians, pharmacists, nurses, physicians, microbiome

The review’s central premise rests on one of the most consequential shifts in modern neuroscience: the recognition that the trillions of microbes inhabiting the human intestine are not passive bystanders in neurological disease but active participants. Multiple sclerosis, in particular, has become a focal point for this line of research. Studies cited in the review show that gut bacteria isolated from patients with multiple sclerosis can worsen disease when transferred into mouse models, driving pro-inflammatory T-cell responses and even enabling spontaneous autoimmune encephalomyelitis in genetically susceptible animals. Conversely, commensal organisms and their metabolic products can protect against central nervous system demyelination. This bidirectional relationship, mediated through immune signaling, metabolites, and the integrity of the intestinal and blood-brain barriers, has opened what many researchers consider a genuine therapeutic frontier.

Where does trehalose fit into this picture? The review lays out several converging mechanisms. First, trehalose is one of the best-characterized dietary inducers of autophagy, a process first described in 2007 when researchers showed that the sugar accelerates the clearance of mutant huntingtin and alpha-synuclein, proteins implicated in Huntington’s and Parkinson’s disease. Unlike rapamycin, trehalose enhances autophagy through an mTOR-independent route, and later work revealed that it also inhibits solute carrier 2A (SLC2A) transporter proteins, contributing to its autophagy-inducing effects. In the context of neuroinflammation, this matters because autophagy in immune cells and glia appears to be essential for recovery from inflammatory damage. Research on experimental autoimmune encephalomyelitis, the standard animal model of multiple sclerosis, has shown that microglial autophagy-associated phagocytosis is required for clearing myelin debris and resolving neuroinflammation, while targeting lipophagy in macrophages improves repair in models of the disease.

Second, trehalose appears to exert direct anti-inflammatory and antioxidant effects that are relevant to the pathological cascade of multiple sclerosis. Experiments in RAW 264.7 macrophages demonstrated that trehalose inhibits inflammatory responses through mitochondrial reprogramming, and separate work showed that the sugar protects cells against oxidative stress by regulating the Keap1-Nrf2 pathway, a master switch of cellular antioxidant defense, in parallel with autophagy activation. In models of Parkinson’s disease, trehalose treatment has repeatedly reduced neurochemical and behavioral deficits, and in vitro studies report attenuation of neurotoxicity through reduced oxidative stress and dampened MAPK and AMPK signaling. The review also highlights a more structural role: trehalose, a well-known chemical chaperone, can stabilize misfolded proteins, and one study found it prevented the spherulite formation of myelin basic protein, the very protein targeted by the autoimmune attack in multiple sclerosis.

The third and perhaps most novel strand of evidence concerns the gut microbiota itself. Both in vitro and animal studies indicate that oral trehalose consumption can shift the abundance of specific microbial groups, including populations associated with the production of short-chain fatty acids, a class of bacterial metabolites that has become central to microbiome-immunology research. Short-chain fatty acids such as propionate and butyrate promote the generation of peripheral regulatory T cells, the immune cells that restrain autoimmune responses, and human studies have repeatedly found that patients with multiple sclerosis show gut dysbiosis and reduced short-chain fatty acid levels. A landmark study published in Cell in 2020 showed that propionic acid shapes the disease course of multiple sclerosis through an immunomodulatory mechanism, and follow-up work demonstrated that propionate promotes neurite recovery in damaged multiple sclerosis neurons. Other clinical studies have linked serum short-chain fatty acid concentrations to disability, T2 lesion counts, inflammatory profiles, and even pediatric onset of the disease.

By potentially enriching short-chain fatty acid-producing bacteria, trehalose could therefore act as a functional food that nudges the gut ecosystem toward an anti-inflammatory configuration. The review notes that these microbiota changes may help modulate intestinal barrier function and systemic immune responses, two factors with direct relevance to multiple sclerosis pathogenesis. Increased intestinal permeability and the resulting systemic inflammation are recognized features of the disease, and animal research has shown that the gut microbiota influences blood-brain barrier permeability in mice, providing a plausible mechanistic route by which a dietary sugar acting in the colon could ultimately affect the central nervous system. Earlier work also showed that trehalose ingestion modifies mucosal immune responses in the small intestine of mice, suggesting the sugar’s immunological reach extends beyond simple microbial feeding.

The authors are careful to situate these findings within the framework of experimental autoimmune encephalomyelitis, the induced model in which autoreactive T cells attack myelin in ways that mirror key features of human multiple sclerosis. In this model, trehalose’s potential to influence neuroprotective pathways and myelin-related processes represents a testable hypothesis rather than an established therapy. The model has been instrumental in dissecting the roles of Th17 cells, which attack the blood-brain barrier, and regulatory T-cell populations, which maintain tolerance, and the review suggests that trehalose’s combined actions on autophagy, inflammatory signaling, and microbiota composition could intersect with all of these cell types. Still, the gap between a mouse model and a heterogeneous human disease marked by relapsing and progressive courses remains substantial.

That caveat is the review’s most important message. Nearly all of the evidence supporting trehalose’s role in multiple sclerosis is preclinical, drawn from cell culture, in vitro colonic models, and animal experiments. Whether oral trehalose can reshape the microbiota of people with multiple sclerosis in the same way it does in laboratory settings is unknown, as are the clinical effectiveness, safety profile, and appropriate dosing of the sugar for this patient population. The authors state plainly that well-structured clinical trials are needed to confirm any therapeutic significance. There are also unresolved scientific questions embedded in the trehalose literature itself, including reports that the sugar can remodel human microbiota in ways that alter the outcome of Clostridioides difficile infection in vitro, a reminder that microbial interventions can cut in unexpected directions depending on context.

Nevertheless, the review makes a persuasive case that trehalose deserves a place in the growing portfolio of microbiota-targeted strategies being explored for multiple sclerosis, alongside fecal microbiota transplantation, propionate supplementation, and dietary interventions. Its appeal lies in its unusual breadth: a single, inexpensive, naturally occurring disaccharide that simultaneously engages autophagy, oxidative stress defenses, protein stabilization, and microbial ecology. As the global prevalence of multiple sclerosis continues to rise according to the Atlas of MS, and as existing disease-modifying therapies leave significant treatment gaps, particularly in neuroprotection and progression, the search for accessible interventions that regulate immunity rather than suppress it has intensified. Trehalose is not a cure, and the authors never claim it is. But as a probe of the microbiota-immunity-brain interface and a candidate for future clinical testing, the sugar that helps desert-dwelling organisms survive dehydration may prove to have unexpected value for the millions of people living with one of neurology’s most stubborn diseases.

Subject of Research: The potential of trehalose to modulate gut microbiota, autophagy, and immune pathways in multiple sclerosis

Article Title: Modulation of gut microbiota by trehalose and its immunomodulatory effects in multiple sclerosis: novel mechanisms and therapeutic perspectives

Article References: Amirpour, S., Parsaei, H., Yaghmayee, S., Banihashemian, S. Z., Forouzanmehr, B., & Eslami, M. (2026). Modulation of gut microbiota by trehalose and its immunomodulatory effects in multiple sclerosis: novel mechanisms and therapeutic perspectives. Food Science and Biotechnology. https://doi.org/10.1007/s10068-026-02339-x

Image Credits: AI Generated

DOI: 10.1007/s10068-026-02339-x

Keywords: trehalose, multiple sclerosis, gut microbiota, autophagy, short-chain fatty acids, neuroinflammation, microbiota-gut-brain axis, experimental autoimmune encephalomyelitis, immunomodulation, demyelination, prebiotics, neuroprotection

The review’s central question was deceptively simple: when people apply topical probiotics, prebiotics, postbiotics, or paraprobiotics, does the composition and diversity of their skin microbiome actually change, and do those microbial shifts translate into measurable clinical improvements? The four categories are biologically distinct. Probiotics are live microorganisms intended to confer a health benefit when applied to the skin surface. Prebiotics are substrates, often specific carbohydrates or fatty alcohols, that are selectively utilized by resident microbes to shift the community’s balance. Postbiotics are inactivated microbial cells or their soluble products, such as ferments and lysates, that retain bioactivity without containing living organisms. Paraprobiotics, sometimes called ghost probiotics, are non-viable microbial cells or cell fragments that can still interact with immune and barrier pathways. Each class modulates the skin’s microbial ecosystem through different mechanisms, and the review treated them as separate intervention strategies rather than a single undifferentiated category.

Methodologically, the studies relied overwhelmingly on 16S ribosomal RNA sequencing, the workhorse technique for profiling bacterial communities. By amplifying and sequencing this conserved yet variable gene region, researchers can estimate microbial richness, calculate alpha and beta diversity indices, and track shifts in taxonomic composition across treated skin sites. The review found that these sequencing-based readouts were frequently paired with physiological measurements, including stratum corneum hydration assessed by corneometry, transepidermal water loss, or TEWL, which serves as a gold-standard proxy for skin barrier integrity, and quantification of inflammatory responses such as erythema. This dual approach, linking molecular ecology to clinical physiology, is what gives the field its translational appeal, because a microbial shift that never changes how skin actually behaves is of limited therapeutic interest.

The disease-specific results offer the most vivid data points. In acne vulgaris, individual studies reported that topical probiotics induced measurable beta-diversity shifts, meaning the overall community structure of the facial microbiome moved toward a distinct configuration after treatment. Within those shifts, some studies documented reductions of up to 29 percent in Cutibacterium acnes, the lipid-dependent bacterium long implicated in acne pathogenesis, alongside increases of up to 23 percent in taxa generally considered favorable, such as Lactobacillus species and Corynebacterium species. In atopic dermatitis, specific studies reported reductions of 27 to 32 percent in Staphylococcus aureus, the opportunistic pathogen whose dominance on lesional skin correlates with flares, barrier breakdown, and inflammatory amplification. A seborrheic dermatitis study observed formulation-dependent reductions of up to 22 percent in Malassezia species, the lipophilic fungi that anchor the fungal arm of the skin microbiome, known as the mycobiome.

Crucially, the review did not stop at microbial counts. In some of the included studies, those ecological shifts were accompanied by improvements in skin physiology that patients would actually notice. Two studies reported hydration increases of 8 to 12 percent, two studies documented TEWL reductions of 12.5 to 24 percent, indicating a tighter, better-sealed barrier, and one study recorded erythema decreases of approximately 10 percent, suggesting a dampening of visible inflammation. The authors also highlight an emerging concept with real diagnostic potential: altered community structures, particularly shifts in the balance between Cutibacterium and Staphylococcus aureus dominance, may serve as biomarkers for the early detection of barrier disruption and disease-related inflammation, potentially before symptoms become clinically obvious.

Yet the authors are emphatic that these numbers must be read with disciplined caution. They explicitly state that the findings should be interpreted as descriptive results from individual studies rather than evidence of a consistent treatment effect across intervention classes. This distinction matters enormously. A systematic review of 17 heterogeneous clinical studies, spanning different formulations, strains, doses, durations, body sites, sequencing protocols, and patient populations, cannot simply pool percentages and declare victory. The 29 percent reduction in C. acnes reported in one acne trial does not predict what a different probiotic cream will do in a different cohort. Without standardized protocols, the field risks building a tower of non-comparable results, each internally valid but collectively unable to support firm clinical guidelines.

The technical limitations compound this problem. Nearly all of the included studies relied on 16S rRNA amplicon sequencing, which classifies bacteria at the genus level and offers limited resolution at the species and strain levels, where much of the functional relevant variation lives. Two strains of the same species can behave in radically different ways, producing distinct metabolites and eliciting distinct immune responses. The authors therefore call for metagenomic profiling, which sequences the entire genetic content of the microbial community and can reveal not just who is present but what metabolic and signaling capabilities they carry. Shotgun metagenomics, combined with metabolomics, would allow researchers to connect specific microbial functions to specific clinical outcomes, moving the field from descriptive ecology toward mechanistic pharmacology.

The breadth of applications explored in the underlying literature is nonetheless remarkable. Beyond the headline conditions of acne, atopic dermatitis, and seborrheic dermatitis, the cited clinical work touches on hyperpigmented skin treated with Pediococcus acidilactici, sensitive scalp syndrome addressed with postbiotic Saccharomyces and Lactobacillus ferment complexes, axillary malodor reduced by live lactobacilli that downregulate odor-producing enzymatic pathways, scalp microbiota and hair quality modulated by fermented fruit biomolecules, and even moisturizers designed to protect the barrier and microbiome against environmental aggressors. There are studies of prebiotic partially hydrolyzed guar gum for hydration, 2-butyloctanol as a prebiotic for the axillary microbiome, and solid lipid nanoparticles loaded with pre- and postbiotics for hand hygiene products that disinfect without sterilizing the resident community. This diversity illustrates both the creativity of the field and the fragmentation of its evidence base.

The deeper scientific context explains why the skin microbiome has become such a compelling therapeutic target. The skin hosts a complex ecosystem of bacteria, fungi, viruses, and mites whose composition varies by body site, sebaceous activity, humidity, and host genetics. Commensal organisms such as Staphylococcus epidermidis contribute directly to barrier homeostasis, for example by generating protective ceramides, while dysbiosis, the loss of community balance, has been documented in psoriasis, rosacea, vitiligo, and wound healing complications, and even linked through the gut-skin axis to systemic conditions. The idea that one could nudge this ecosystem back toward health with carefully chosen biotics, rather than carpet-bombing it with antibiotics, represents a genuinely paradigm-shifting approach to dermatology, one that treats microbes as allies to be cultivated rather than enemies to be eradicated.

Where does this leave consumers confronted with a growing shelf of microbiome-branded serums and creams? The review’s verdict is best understood as a call to rigor rather than a dismissal. The evidence shows that topical biotics can measurably reshape the skin’s microbial landscape and, in some studies, improve hydration, barrier function, and inflammation, but the field lacks the standardized clinical protocols and deeper molecular profiling needed to establish efficacy with confidence or to enable truly personalized probiotic-based interventions. The authors’ roadmap is clear: harmonized trial designs, metagenomic and multi-omic profiling, and larger controlled cohorts that can distinguish strain-specific effects from formulation artifacts. Until then, the skin microbiome remains one of dermatology’s most exciting frontiers, a living ecosystem whose careful cultivation may one day transform how we treat acne, eczema, and aging skin, but whose clinical exploitation still awaits the discipline that only systematic, standardized science can provide.

Subject of Research: Effects of topical probiotics, prebiotics, postbiotics, and paraprobiotics on the human skin microbiome in dermatological disease

Article Title: Topical probiotics, prebiotics, postbiotics, and paraprobiotics for modulating the skin microbiome: a systematic review of clinical studies

Article References: Nguyen, T. T. M., Jin, X., Zheng, Q., Yi, G.-S., Yang, S.-J., Yi, E.-J., Gwak, Y.-S., Kim, M.-J., Choi, J., & Yi, T.-H. (2026). Topical probiotics, prebiotics, postbiotics, and paraprobiotics for modulating the skin microbiome: a systematic review of clinical studies. Archives of Dermatological Research, 318(1), Article 517. https://doi.org/10.1007/s00403-026-04998-6

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04998-6

Keywords: skin microbiome, probiotics, prebiotics, postbiotics, paraprobiotics, acne vulgaris, atopic dermatitis, seborrheic dermatitis, 16S rRNA sequencing, transepidermal water loss, Cutibacterium acnes, Staphylococcus aureus

In vitro gut models occupy a crucial middle ground between animal experiments and human trials. They allow researchers to expose standardized microbial communities to defined substrates, then measure exactly which bacteria bloom and which metabolites accumulate. Yet the field has been constrained by a persistent trade-off. Simple batch systems are easy to scale but leave important parameters, most notably colonic pH, uncontrolled, which distorts microbial ecology because pH is one of the strongest determinants of which taxa can survive. More sophisticated multi-compartment simulators can hold pH, temperature and oxygen tension steady, but they are expensive, bulky and low-throughput, meaning researchers can test only a handful of conditions at a time. HUGS was designed specifically to break this compromise by replicating ascending colon conditions, including controlled pH, anaerobiosis and temperature, while remaining experimentally scalable.

The technical heart of the platform is its parallel fermentation architecture. In a single run, 32 vessels operate side by side, each functioning as an independent mini-colon with its own pH regulation. This means a researcher can test dozens of substrate formulations, doses or combinations in one day rather than spreading them across weeks of sequential experiments. The authors emphasize that the model simulates the passage of material through the colon while maintaining the environmental controls that more complex simulators provide. Because each fermentation is independent, statistical comparisons between treatments rest on genuine biological replication rather than on repeated sampling from a single shared reactor, which strengthens the interpretability of downstream sequencing and metabolite data.

To validate the system, the team put it to work on a panel of plant-derived substrates connected to the European Union-funded EnXylascope project, which received support from the Horizon 2020 Research and Innovation program under grant agreement No 101000831. The substrates included fermented and unfermented rapeseed meal, fermented and unfermented soybean meal, seaweed, and different xylans, an enzyme-modified xylan, a GH115-modified xylan and a control xylan, tested both individually and in various combinations. Fermentation of plant meals before colonic exposure is of particular interest because microbial pre-digestion can change which fibers and proteins reach the gut microbiome, potentially reshaping its composition and metabolic output. The abbreviations used in the study, from FSBM for fermented soybean meal to FSBMS for its combination with seaweed, reflect the systematic factorial design the platform was built to handle.

Measuring what happened inside the mini-colons required two complementary analytical approaches. The composition of the resulting in vitro colonic microbiome was determined by 16S rRNA gene amplicon sequencing, the standard method for cataloguing bacterial communities, while short-chain fatty acid production was quantified by ion-exchange chromatography. Short-chain fatty acids, including acetate, propionate and butyrate, are the principal metabolic currency of the colonic microbiome, produced when bacteria ferment dietary fiber, and they influence gut health, inflammation and even distant organs. Quantifying them alongside community composition allows researchers to distinguish between substrates that merely change which bacteria are present and those that genuinely alter microbial metabolic activity, a distinction central to screening dietary fibers and microbiome-modulating compounds.

The validation results were encouraging on the fundamentals. The HUGS model supported the growth of key anaerobic gut microorganisms, including Faecalibacterium prausnitzii, a butyrate-producing bacterium widely associated with gut health, and Akkermansia muciniphila, a mucin-degrading species that has attracted intense interest for its links to metabolic health. Equally important, the model preserved the dominant phylum-level characteristics of the original fecal microbiomes used as inocula, meaning the communities that developed in the vessels remained recognizably human rather than drifting toward laboratory artifacts. As is commonly observed in short-term in vitro colon models, alpha diversity decreased following fermentation, but the obligate anaerobic taxa that define a healthy colonic community remained abundant throughout the experiments, indicating that the anaerobic conditions inside the vessels were being maintained effectively.

When the team turned to the substrate treatments themselves, the picture was more nuanced. Overall, the different substrate treatments did not produce distinct clustering patterns in the community data, meaning that at the level of whole-community structure, the fermentations looked broadly similar regardless of what the bacteria were fed. However, differential abundance analysis, which examines individual taxa rather than global patterns, identified substrate-dependent shifts that were biologically meaningful. Fermentations containing fermented plant materials showed increased relative abundance of Akkermansia muciniphila and Leuconostoc citreum, a lactic acid bacterium, together with reduced abundance of Cutibacterium acnes and Clostridium perfringens, the latter a species with well-known pathogenic potential. These targeted shifts suggest that fermentation pre-treatment of plant meals can nudge the microbiome in directions that may be nutritionally relevant, even when the overall community architecture stays stable.

Metabolic readouts told a similarly subtle story. Short-chain fatty acid production varied between substrate formulations, and one difference rose to statistical significance: a reduction in total SCFA concentration, with an adjusted p-value of 0.016, following xylan supplementation of the fermented soybean meal and seaweed formulation. That a fiber addition reduced rather than increased total SCFA output in that particular context illustrates exactly why high-throughput, well-controlled screening matters. Fiber effects are highly context-dependent, shaped by the baseline community, the other substrates present and the specific chemical structure of the fiber, and only a platform that can test many combinations in parallel with proper replication can map that interaction space efficiently. The statistical machinery applied to the data, including principal coordinate analysis, permutational multivariate analysis of variance and Tukey’s honestly significant difference testing, reflects the rigor the platform enables.

The authors propose HUGS as a promising platform for high-throughput screening of dietary fibers, feed additives and microbiome-modulating compounds in both fundamental and translational future research. The implications extend beyond human nutrition. Because the same logic applies to animal feed, the platform could serve agricultural biotechnology companies evaluating how feed additives reshape livestock gut microbiomes, and it could help functional food developers substantiate claims about prebiotic ingredients before expensive clinical trials. The work was conducted under the EnXylascope project, whose focus on xylan-degrading enzymes aligns with the substrate panel tested, and the study received ethical approval from the Ethical Committee of the Capital Region of Denmark under registration number H-20028549, with the authors declaring no competing interests.

What makes the HUGS advance notable is not any single feature but the combination it achieves. Controlled pH, robust anaerobiosis, preservation of key anaerobic taxa and sensitivity to substrate-dependent responses have each been demonstrated before in individual systems, but rarely together with 32-fold parallelization in a 24-hour run. If the platform performs as well in other laboratories as it did in this validation, it could accelerate the pace at which candidate prebiotics, enzymes and microbiome therapies move from hypothesis to evidence, compressing screening timelines that currently stretch over months into days. For a field where the complexity of the gastrointestinal microbiome and its interactions with food components and other environmental factors remains only partly understood, tools that make that complexity experimentally tractable at scale are a welcome addition to the arsenal.

Subject of Research: High-throughput in vitro simulation of the human colonic microbiome for testing dietary fibers and plant-derived substrates

Article Title: The novel HUGS colon model enables high-throughput parallel cultivation of metabolically active human gut microbiomes in vitro

Article References: Beck, F., Gottumukkala, L. D., Pedersen, N. R., & Nielsen, D. S. (2026). The novel HUGS colon model enables high-throughput parallel cultivation of metabolically active human gut microbiomes in vitro. Scientific Reports. https://doi.org/10.1038/s41598-026-72614-8

Image Credits: AI Generated

DOI: 10.1038/s41598-026-72614-8

Keywords: gut microbiome, in vitro colon model, HUGS, high-throughput fermentation, short-chain fatty acids, 16S rRNA sequencing, dietary fiber, xylan, Faecalibacterium prausnitzii, Akkermansia muciniphila, anaerobic culture, prebiotics

The scale of the problem gives the review its urgency. Global burden analyses cited by the authors show that atopic dermatitis has risen steadily over recent decades, imposing substantial physical, psychological, and economic costs, particularly in children. Conventional treatments, from topical corticosteroids to the interleukin-targeting biologic dupilumab, are effective for many patients but do not address the underlying immune dysregulation for everyone, and long-term use raises practical concerns. Against this backdrop, the research team conducted a systematic search of PubMed, Web of Science, and Scopus covering studies published between January 2016 and March 2025. Of 1,247 unique records identified, 69 studies met the inclusion criteria, forming the evidentiary backbone of the review. The authors evaluated each clinical study with attention to design, sample size, effect size, risk of bias, and reproducibility, an approach that lends the work unusual critical rigor for a field crowded with small and heterogeneous trials.

At the mechanistic heart of the review lies the chemistry of microbial metabolites. Gut bacteria ferment dietary fiber into short-chain fatty acids, chiefly acetate, propionate, and butyrate, molecules with far-reaching effects on host physiology. These metabolites regulate the differentiation of regulatory T cells, the immune cells that restrain inflammatory responses, and help maintain the delicate balance between Th1 and Th2 helper cell lineages that is characteristically skewed toward Th2-driven inflammation in atopic dermatitis. Butyrate also acts epigenetically, inhibiting histone deacetylases in immune cells and thereby tuning gene expression programs of macrophages. Beyond the gut, experimental work cited in the review shows that short-chain fatty acids can promote keratinocyte metabolism and differentiation, directly strengthening the skin barrier. In other words, the products of gut bacteria appear to reach out and remodel the very tissue that eczema attacks.

A second chemical pathway involves tryptophan, an essential amino acid that gut microbes convert into derivatives engaging the aryl hydrocarbon receptor, a transcription factor with pivotal roles in barrier organ physiology and immune regulation. Activation of this receptor promotes interleukin-22 signaling, which supports epithelial integrity in both gut and skin. The review highlights evidence that a tryptophan metabolite produced by skin bacteria attenuates inflammation in patients with atopic dermatitis through this same receptor, suggesting that microbial chemistry operates on both ends of the gut–skin axis. Intriguingly, epidemiological studies have linked low fecal concentrations of valeric acid, another short-chain fatty acid, in one-year-old children to the later development of eczema and food allergy at age thirteen, and children raised on farms, with their rich microbial exposures, show higher valeric acid levels and lower eczema risk. These findings hint that metabolite profiles measured in infancy might one day serve as predictive biomarkers.

Barrier function provides a third mechanistic thread. The review describes how a compromised intestinal epithelium, sometimes called leaky gut, permits translocation of microbial components such as lipopolysaccharide into the circulation, fueling systemic low-grade inflammation that can amplify skin disease. Studies in children have associated elevated serum lipopolysaccharide-binding protein with sensitization to food allergens, connecting gut permeability to the allergic diathesis more broadly. Microbial metabolites counteract this process: short-chain fatty acids enhance intestinal epithelial barrier function through crosstalk with hypoxia-inducible factor signaling, tightening junctions and reducing permeability. The review also touches on neuroimmune interactions, noting that altered gut and skin microbiota modulate itch, the symptom patients often rate as most burdensome, through pathways that connect the microbiota to the nervous system via the microbiota–gut–brain axis and vagal afferent signaling.

Turning from mechanisms to medicine, the review assesses the clinical evidence for microbiome-targeted interventions, and here the picture is one of genuine but qualified promise. The strongest support comes from high-quality randomized controlled trials of specific probiotic strains in pediatric atopic dermatitis. Lacticaseibacillus rhamnosus GG, administered at a dose of 1 × 10^10 colony-forming units per day, and Bifidobacterium bifidum have both produced modest but statistically significant improvements in SCORAD scores, the standard severity measure, and in quality of life. The ProPAD trial, which tested Lacticaseibacillus rhamnosus GG in children, is among the studies the authors highlight as methodologically credible. Meta-analyses of probiotic trials in children and, more recently, in adults broadly corroborate a small treatment effect, though the review is careful to note that results vary considerably across strains, doses, and populations.

Evidence for the other intervention categories is thinner. Prebiotics, nondigestible compounds that selectively feed beneficial bacteria, have produced encouraging results in individual trials, such as a study of kestose that increased Faecalibacterium prausnitzii and improved symptoms in infants with atopic dermatitis, but the overall literature remains limited. Synbiotics, which combine probiotics and prebiotics, showed benefit in a double-blind randomized trial of infants under one year of age when paired with vitamin D3, yet replication is lacking. Postbiotics, defined as preparations of inactivated microbes or their metabolites, represent an intriguing safety-oriented alternative but are at an even earlier stage of evaluation. Dietary interventions, including high-fiber and plant-based diets, are supported by observational associations, such as a cross-sequential study of young adults in Singapore and Malaysia linking frequent intake of high-fiber and probiotic diets to lower atopic dermatitis risk, but causal evidence from randomized trials is sparse. Fecal microbiota transplantation, the most radical option, has produced striking signals: a randomized, double-blind controlled trial published in Allergy in 2025 tested it against moderate-to-severe atopic dermatitis in adults, and an earlier Israeli study reported clinical efficacy in adults with moderate-to-severe disease. Yet the review stresses that transplantation carries documented risks, including a well-known case of drug-resistant E. coli bacteremia transmitted by a fecal transplant, underscoring the need for rigorous donor screening.

The authors are candid about the gaps that separate current enthusiasm from clinical practice. Optimal strain selection, dosing, treatment duration, and long-term safety remain unresolved, and there are no validated mechanistic biomarkers to predict which patients will respond. Many trials are small, use heterogeneous outcome measures, and underreport harms, a deficiency documented in systematic reviews of microbiota intervention studies. Strain-level specificity matters enormously: the review cites evidence that subspecies-level dysbiosis of Faecalibacterium prausnitzii underlies atopic dermatitis, implying that interventions must be matched to precise microbial deficits rather than generic notions of healthy flora. The authors also emphasize reproducibility, noting that positive findings from single centers frequently fail to generalize across populations with different genetic backgrounds, diets, and baseline microbiomes.

Looking forward, the review lays out a research agenda that reads like a blueprint for the next decade of microbiome medicine. The authors call for well-powered, long-term randomized controlled trials with standardized outcome measures, integration of multi-omics approaches spanning genomics, metabolomics, and immunology, and personalized strategies that account for age, genetics, and baseline microbial composition. The concept of personalization draws on precedents such as predictive algorithms for glycemic responses, suggesting that microbiome-guided dermatology could eventually tailor probiotic or dietary prescriptions to an individual’s microbial fingerprint. For now, the authors conclude, gut microbiome modulation is not ready to replace conventional atopic dermatitis therapies, but it stands as a promising complementary strategy, one that transforms the gut from an unlikely organ in a skin disease into a legitimate target for rigorous therapeutic investigation.

Subject of Research: Gut microbiome-based interventions for the treatment of atopic dermatitis

Article Title: Gut microbiome‑based interventions for treatment of atopic dermatitis—a mini review

Article References: Cui, X., Li, C., Zhang, H., & Yuan, X. (2026). Gut microbiome‑based interventions for treatment of atopic dermatitis—a mini review. Archives of Dermatological Research, 318(1), Article 465. https://doi.org/10.1007/s00403-026-04926-8

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04926-8

Keywords: gut microbiome, atopic dermatitis, gut-skin axis, probiotics, short-chain fatty acids, tryptophan metabolites, fecal microbiota transplantation, prebiotics, synbiotics, regulatory T cells, skin barrier, eczema

The central concept in the review is bioavailability, defined as the proportion of ingested magnesium that is absorbed and utilized by the body. This is where the science becomes technically interesting, because the number printed on a supplement label reflects only the total elemental magnesium content of the compound, not how much of it will survive the journey through the gastrointestinal tract and into circulation. Magnesium oxide, one of the cheapest and most common forms on the market, delivers a high elemental load but dissolves poorly in intestinal fluids, and comparative studies have repeatedly shown that more soluble salts outperform it. In a randomized cross-over study, magnesium citrate produced higher urinary excretion and serum levels than magnesium oxide after single-dose administration, and earlier work comparing the two salts reached similar conclusions.

The review organizes supplement forms into a hierarchy of chemical classes: inorganic salts such as oxide and chloride, organic salts such as citrate, lactate, and aspartate, chelated forms in which magnesium is bound to amino acids, and advanced formulations that use encapsulation or controlled-release technology. Organic salts and chelates generally offer better solubility, gastrointestinal tolerability, and bioavailability than magnesium oxide, although the authors caution that outcomes vary with the specific formulation, the dose, the food matrix consumed alongside it, and individual physiological characteristics. In other words, there is no single universal winner; the performance of a magnesium product emerges from an interaction between chemistry and context.

Understanding how the intestine absorbs magnesium helps explain these differences. Absorption occurs along the small intestine and, to a lesser extent, the colon through two mechanistically distinct pathways. At low luminal concentrations, magnesium crosses the epithelium via saturable, transcellular channels, a process that can be regulated according to the body’s magnesium status. When luminal concentrations rise, a second, paracellular pathway allows magnesium to flow between cells down its electrochemical gradient in a non-saturable manner. This dual system has a practical consequence that many consumers miss: very large doses do not proportionally increase absorption, because the saturable pathway becomes overwhelmed and the passive pathway captures only a fraction of the remaining load. Splitting a dose or choosing a form that dissolves efficiently can therefore matter more than simply taking more milligrams.

Dietary context exerts a powerful influence on how much magnesium the gut actually takes up, and the review details both the enhancers and the saboteurs. On the positive side, fermentable fibers such as inulin, fructo-oligosaccharides, galactooligosaccharides, resistant starch, and resistant maltodextrin stimulate microbial fermentation in the colon, lowering pH and promoting mineral solubility and absorption. Human studies have shown that five weeks of short-chain fructo-oligosaccharide intake increased intestinal magnesium absorption and status in postmenopausal women, and similar benefits have been documented in adolescent girls. Proteins and medium-chain triglycerides also support absorption; medium-chain fatty acids improved calcium and magnesium uptake in patients with intestinal resections, and medium-chain triglyceride feeding enhanced mineral absorption in premature infants.

On the inhibitory side of the ledger sit phytate, oxalic acid, and certain polyphenols, all of which form poorly soluble complexes with magnesium ions in the gut lumen. Phytic acid added to white wheat bread significantly reduced fractional apparent magnesium absorption in human subjects, and spinach, a vegetable rich in both magnesium and oxalate, delivered less absorbable magnesium than kale, which has a low oxalate content despite comparable mineral content on paper. These findings carry a counterintuitive message: a food can be chemically rich in magnesium yet nutritionally poor as a source of it. Food processing can shift the balance, however, because sourdough fermentation activates endogenous phytase enzymes and a moderate pH decrease is sufficient to degrade much of the phytate in whole wheat flour, restoring the bioavailability of the grain’s minerals.

The review also highlights how formulation technology is reshaping the supplement landscape. Microencapsulated magnesium products, in which the mineral is wrapped in protective coatings, have shown improved absorption and fewer gastrointestinal side effects in comparative clinical studies. Sucrosomial magnesium, a formulation in which the mineral is carried inside phospholipid vesicles, demonstrated favorable bioavailability in both ex vivo work and a double-blinded cross-over study in healthy subjects. Extended-release matrices offer a different strategy: a magnesium lactate dihydrate extended-release caplet showed measurable absolute bioavailability in healthy volunteers, with the slow release designed to avoid saturating the intestinal transport pathways. These advanced systems reflect a growing recognition that the delivery vehicle is as important as the salt itself.

Measuring bioavailability remains a methodological challenge, and the review surveys the tools researchers use to compare forms. Stable isotope techniques allow true fractional absorption to be tracked from a labeled dose, while urinary excretion after single doses or in magnesium-saturated subjects provides a practical proxy. Serum and circulating ionized magnesium, intracellular magnesium in leukocytes measured by X-ray dispersion analysis, and in vitro models such as Caco-2 intestinal barrier cell cultures each add complementary evidence, though animal studies, including rat work comparing ten organic and inorganic magnesium salts, sometimes show smaller differences between forms than human trials, particularly when diets are high in phytic acid. The authors argue that supplementation should be assessed beyond elemental content alone, considering absorption, retention, and ultimately tissue utilization.

For the growing population of consumers reaching for magnesium to support sleep, muscle recovery, or cardiovascular health, the practical takeaway is nuanced. The form matters, with citrate, organic salts, and chelates generally outperforming oxide; the dose and timing matter, because absorption efficiency declines as dose rises; and the meal matters, because phytate-rich and oxalate-rich foods can bind magnesium while fermentable fibers, adequate protein, and medium-chain triglycerides can enhance its uptake. Individual factors, including age-related changes in gut function and the presence of intestinal disease or resection, further modulate how much of any given dose the body retains. As the review concludes, evaluating a magnesium supplement requires looking past the label’s elemental magnesium number to the chemistry of the salt, the sophistication of the formulation, and the dietary environment in which it is taken, a framing that may finally bring rigor to one of the supplement industry’s most crowded categories.

Subject of Research: Magnesium bioavailability, intestinal absorption mechanisms, and comparative performance of dietary supplement forms

Article Title: Advances in magnesium bioavailability: dietary factors, absorption mechanisms, and comparative performance of supplement forms

Article References: Gultekin, S., & Tomas, M. (2026). Advances in magnesium bioavailability: dietary factors, absorption mechanisms, and comparative performance of supplement forms. Food Science and Biotechnology. https://doi.org/10.1007/s10068-026-02319-1

Image Credits: AI Generated

DOI: 10.1007/s10068-026-02319-1

Keywords: magnesium, bioavailability, intestinal absorption, dietary supplements, magnesium citrate, magnesium oxide, phytate, oxalate, prebiotics, microencapsulation, chelated minerals, nutritional deficiency

The study, published in MicrobiologyOpen, was led by scientists at Teagasc, the Irish agriculture and food development authority, working with strains from their culture collection and the German Collection of Microorganisms and Cell Cultures. Their motivation was twofold. First, the global mannitol market, valued at roughly 451 million US dollars in 2024 and growing at about 5 percent annually, depends on a process that consumes energy and generates an unwanted co-product. Second, microbial fermentation offers an inherently gentler alternative: it runs at atmospheric pressure, at mild temperatures between 30 and 37 degrees Celsius, and can in principle use cheap agricultural feedstocks instead of pure sugars. The catch has always been that complex plant carbohydrates usually need to be broken down into fructose before microbes can turn them into mannitol, adding a costly processing step.

The Irish team’s insight was to pick a feedstock whose fructose chains are short enough for the bacteria to handle on their own. Yacon, Smallanthus sonchifolius, is a tuber native to the Andes that stores much of its carbohydrate as fructooligosaccharides, or FOS, polymers of fructose with a degree of polymerization typically no greater than ten. The researchers obtained yacon root powder, prepared by spray-drying yacon syrup from a grower in County Kilkenny, Ireland, where the crop has been trialed successfully in temperate conditions. Chemical analysis showed the powder contained 54.8 percent FOS by weight, along with 31.1 percent free sugars, mostly fructose, glucose and sucrose. Chromatographic profiling revealed that most of the FOS chains carried between four and six fructose units, making them considerably less complex than the inulin found in Jerusalem artichoke or chicory.

To ferment this material, the team screened ten strains of fructophilic lactic acid bacteria, or FLAB, belonging mainly to the genera Leuconostoc and Fructobacillus, all previously isolated from flowers on an Irish farm, including cotoneaster, dandelion and white clover blossoms. These bacteria thrive in fructose-rich environments such as nectar and are known to tolerate fructose concentrations of up to 40 percent. Crucially, genome analysis of one strain, Leuconostoc mesenteroides DPC7261, identified two genes encoding glycoside hydrolases carrying the GH32 domain, the enzymatic signature of invertases and inulinases, suggesting the bacteria could cleave yacon FOS into fructose themselves. That endogenous enzymatic toolkit is what makes a single-step, consolidated bioprocess possible.

The screening results were striking. When grown for 20 hours in laboratory medium containing 1 percent yacon root powder at 30 degrees Celsius, all ten flower-derived FLAB strains produced between 4 and 5 grams of mannitol per liter. The official type strains of the same species fared noticeably worse, producing less than 3 grams per liter, and the gap was especially pronounced for Fructobacillus fructosus, where the flower isolates yielded roughly twice as much mannitol as the type strain. A comparison strain, Limisolactobacillus fermentum, which has been reported to make mannitol from pure fructose, managed less than 3 grams per liter on yacon powder, even though it produced over 10 grams per liter when given plain fructose. The flower isolates, in other words, were uniquely suited to the untreated FOS substrate.

From the screen, the researchers focused on two strains: Fructobacillus fructosus DPC 7237, from white clover flowers, and Leuconostoc mesenteroides DPC 7246, from cotoneaster flowers. Although the Fructobacillus strains produced slightly higher peak titers, they flocculated strongly regardless of agitation, complicating cell density measurements and consistent inoculation. Leuconostoc mesenteroides DPC 7246 grew more robustly and was less demanding about oxygen levels, so it became the workhorse for optimization and scale-up. Time-course experiments showed mannitol production peaked between 16 and 20 hours, reaching 5.1 grams per liter for DPC 7246 and 5.5 grams per liter for DPC 7237, before declining after 24 hours. The researchers suggest that because the mannitol dehydrogenase reaction is reversible, the bacteria may reconsume mannitol to support central metabolism or regenerate cofactors once fructose runs low.

The team then tested whether temperature, agitation or substrate loading could push titers higher. Raising the temperature to 37 degrees Celsius or removing agitation brought no significant improvement, so subsequent work proceeded at 30 degrees Celsius with mild shaking. Doubling the yacon powder concentration to 2 percent increased peak mannitol by only about a third, and the extra substrate shifted the bacterium’s metabolism: ethanol appeared as a by-product, lactic acid rose, acetic acid fell, and the yield of mannitol per gram of FOS dropped from 0.92 to 0.635 grams. This overflow metabolism, in which surplus fructose is routed through the pentose phosphate pathway and ultimately into ethanol, suggests that simply loading more substrate is not enough; future processes will likely need fed-batch strategies to keep fructose flowing at a rate the cells can channel into mannitol.

The critical test came at scale. Moving from 15-milliliter tubes to 200-milliliter benchtop bioreactors, with controlled heating and mixing but no aeration and no pH adjustment, the researchers found that mannitol production peaked at 6.7 grams per liter, essentially unchanged from small-scale results, and actually arrived earlier, at 24 to 28 hours rather than 32. A post-hoc comparison across volumes showed titers of 6.55 grams per liter at 15 milliliters and 6.38 grams per liter at 200 milliliters at the 24-hour mark, both exceeding the 5.73 grams per liter seen in 40-milliliter shake flasks, where extra aeration appears to have altered the cells’ redox balance and reduced their need to regenerate NAD+ via mannitol. Accounting for the FOS content of the powder, the peak yields at bioreactor scale were 0.61 to 0.62 grams of mannitol per gram of FOS at both temperatures tested.

Those yields stand up well against the published literature on complex substrates. Fermentation of hydrolyzed inulin has delivered 0.58 grams per gram, chicory-derived inulin hydrolysate 0.69 grams per gram, and Jerusalem artichoke extract 0.68 grams per gram, but all of those required the feedstock to be saccharified before fermentation. Uncracked, unhydrolyzed substrates have generally performed far worse: Jerusalem artichoke juice fermented directly by Lactobacillus casei strains yielded only about 3.6 grams of mannitol per liter, compared with the 4 to 5 grams per liter the Irish strains achieved from yacon powder at screening concentrations. The researchers attribute this advantage to the short chain length of yacon FOS, which allows the bacteria’s own enzymes to hydrolyze and ferment the substrate simultaneously, a genuine consolidated bioprocess.

The work remains a proof of concept, and the authors are candid about the hurdles ahead. Titer and productivity must rise substantially to compete industrially, which will demand higher substrate concentrations, strains with greater fructose tolerance, cheaper nitrogen sources such as tryptone or corn steep liquor to replace the complex laboratory medium, and feeding strategies that suppress ethanol formation. Yet the underlying proposition is compelling: a natural, plant-based fructooligosaccharide from a tuber that grows well in temperate climates, converted by food-safe bacteria at mild temperatures into a sweetener with a low glycaemic index and applications spanning food and pharmaceuticals, all in one vessel and one step. As demand grows for sugar substitutes that do not carry the metabolic baggage of sucrose, the humble yacon tuber and its flower-borne microbial partners may have earned a place in the industrial biotechnology spotlight.

Subject of Research: Microbial production of mannitol from yacon fructooligosaccharides using fructophilic lactic acid bacteria

Article Title: Single‐Step Production of Mannitol From Yacon Fructo‐Oligosaccharides Using Fructophilic Lactic Acid Bacteria

Article References: Rajkumar, A. S., Leech, J., & McAuliffe, O. (2026). Single‐Step Production of Mannitol From Yacon Fructo‐Oligosaccharides Using Fructophilic Lactic Acid Bacteria. MicrobiologyOpen, 15(5), Article e70387. https://doi.org/10.1002/mbo3.70387

Image Credits: AI Generated

DOI: 10.1002/mbo3.70387

Keywords: mannitol, yacon, fructooligosaccharides, fructophilic lactic acid bacteria, Leuconostoc mesenteroides, Fructobacillus fructosus, fermentation, biotechnology, sweeteners, consolidated bioprocessing, prebiotics, sustainable food production

The enzyme, named BWbg1, belongs to a class of proteins known as beta-galactosidases, which catalyze the cleavage of lactose, the disaccharide sugar that makes up a large fraction of the solids in milk, into its two component monosaccharides, glucose and galactose. Beta-galactosidases have long occupied a central place in dairy biotechnology because they support two distinct and commercially significant applications. The first is the production of low-lactose and lactose-free milk and dairy goods for the large population of people who cannot properly digest lactose. The second is the synthesis of galacto-oligosaccharides, or GOS, through transgalactosylation reactions in which the enzyme, instead of simply splitting lactose, stitches galactose units together into short chains that humans cannot digest but that beneficial gut bacteria eagerly consume.

What makes BWbg1 stand out in a crowded field of known beta-galactosidases is its thermal profile. The purified enzyme exhibits maximum activity at 80 degrees Celsius and at a neutral pH of 7, a combination that immediately distinguishes it from the mesophilic enzymes traditionally used in dairy processing. It also demonstrates impressive resilience, retaining more than 72 percent of its activity after six hours of incubation at 55 degrees Celsius. For industrial operators, these are not merely laboratory curiosities. Elevated operating temperatures increase the initial productivity of enzymatic reactions, improve the solubility of substrates such as concentrated lactose solutions, and dramatically reduce the risk of contamination by spoilage and pathogenic microorganisms, which struggle to proliferate at temperatures that the enzyme tolerates with ease.

The path to BWbg1 illustrates the power of functional metagenomic screening, a technique that has become one of the most productive strategies in modern bioprospecting. Rather than trying to culture the microorganisms from the As Burgas hot spring, an approach that would capture only a small fraction of the community because most environmental microbes resist laboratory cultivation, the researchers extracted the collective DNA of the entire microbial ecosystem and cloned it into a metagenomic library. They then screened that library for clones exhibiting beta-galactosidase activity, allowing the function of the gene itself, rather than any prior knowledge of the organism that carried it, to guide the discovery. Sequence analysis of the protein encoded by the recovered gene revealed that BWbg1 belongs to glycoside hydrolase family 35, a well-characterized group of enzymes, yet its properties proved distinctive enough to warrant the label of novelty.

The enzyme’s performance in GOS synthesis is arguably its most commercially compelling feature. Working with a concentrated lactose solution of 40 percent weight per volume at 70 degrees Celsius, BWbg1 converted the substrate into a product mixture containing up to 48 percent galacto-oligosaccharides by weight over a four-hour reaction. That yield, achieved at a temperature at which most conventional enzymes would rapidly denature, positions BWbg1 as a serious candidate for industrial prebiotic production. GOS are among the most widely added prebiotics in infant formula and functional foods, valued for their ability to selectively stimulate the growth of beneficial bacteria such as Bifidobacteria in the gut. A thermostable enzyme that can sustain high-yield synthesis at 70 degrees Celsius offers manufacturers both faster throughput and a substantially lower microbial contamination risk during extended production runs.

Perhaps the most surprising finding, however, concerns what happens when the enzyme is exposed to heat before it is asked to work. The researchers observed a remarkable heat activation effect: after two hours of incubation at 65 degrees Celsius, BWbg1’s ability both to hydrolyze lactose and to produce GOS was enhanced rather than diminished. This behavior has direct implications for how the enzyme could be deployed in real dairy plants. Milk destined for the market is routinely pasteurized, and the two dominant methods are HTST, high-temperature short-time pasteurization, and VAT, the older vat pasteurization approach that uses lower temperatures over longer holding periods. The study demonstrated that BWbg1 retains its activity after both HTST and VAT pasteurization of commercial milk, and that the heat activation it experiences during these treatments actually improves its subsequent performance on the lactose in the milk.

This compatibility with pasteurization regimes is a genuinely practical advantage. In current industrial practice, lactose hydrolysis is typically performed as a separate step after pasteurization, requiring additional equipment, time, and careful hygiene controls. An enzyme that can be added to milk, survive the pasteurization step itself, and then go on to work more effectively afterward could allow manufacturers to merge two processing stages into one streamlined operation. The enzyme’s tolerance of the exact thermal conditions used to make milk safe for consumers means that the same heat treatment that protects public health simultaneously primes the biocatalyst for action, a coincidence of process requirements that enzyme engineers usually struggle to achieve by design.

Equally noteworthy is the enzyme’s behavior at the opposite end of the temperature scale. The study reports that BWbg1 remains capable of hydrolyzing lactose from commercial milk and producing GOS even at 8 degrees Celsius, a temperature within the range of standard refrigerated storage. This cold activity opens the door to applications in which milk is treated during chilled logistics or storage, extending the enzyme’s usefulness well beyond the hot processing floor. A single biocatalyst that functions productively from refrigeration temperatures up to 80 degrees Celsius spans a thermal range that few, if any, commercially established beta-galactosidases can match, and it gives process designers an unusual degree of freedom in choosing where and when in the production chain to deploy it.

The broader significance of the work lies in what it says about the untapped enzymatic wealth of extreme environments. Hot springs have long been recognized as reservoirs of thermostable proteins, because the microorganisms adapted to life at elevated temperatures must maintain enzymes that keep their structure and function under conditions that would destroy the proteins of ordinary organisms. Yet the vast majority of these thermophilic communities remain genetically uncharacterized, and functional metagenomics offers a way to access their catalytic repertoire without ever growing a single cell in the laboratory. The As Burgas spring, flowing through a geologically active region of Galicia, proved to be a productive hunting ground, and the researchers suggest that BWbg1’s versatility, spanning lactose hydrolysis, GOS synthesis, pasteurization compatibility, and cold-temperature activity, makes it a strong candidate for industrial application.

For consumers, the practical outcome of such research is tangible. Lactose intolerance affects a substantial share of the global population, and demand for lactose-free dairy continues to climb, while the market for prebiotic ingredients that support gut health grows in parallel. An enzyme that can serve both markets, converting milk into a digestible product for one consumer group and into a GOS-enriched functional food for another, addresses two major trends in food science with a single biocatalyst. As the team’s results demonstrate, the answer to some of the dairy industry’s most persistent processing challenges may have been waiting all along in the steaming waters of a Spanish hot spring, encoded in the genomes of microbes no one has ever cultured.

Subject of Research: A thermostable GH35 beta-galactosidase from a hot spring metagenome for lactose hydrolysis and galacto-oligosaccharide production in milk

Article Title: A novel thermostable beta-galactosidase for low-lactose and galacto-oligosaccharide-rich milk

Article References: DeCastro, M.-E., Becerra-Fernández, M., Rodríguez-Belmonte, E., & González-Siso, M.-I. (2026). A novel thermostable beta-galactosidase for low-lactose and galacto-oligosaccharide-rich milk. Applied Microbiology and Biotechnology. https://doi.org/10.1007/s00253-026-14045-z

Image Credits: AI Generated

DOI: 10.1007/s00253-026-14045-z

Keywords: beta-galactosidase, metagenomics, thermostable enzyme, galacto-oligosaccharides, lactose-free milk, hot spring, bioprospecting, dairy biotechnology, prebiotics, pasteurization, GH35, transgalactosylation

The team’s strategy rests on the Maillard reaction, the same non-enzymatic chemistry that browns bread crust and sears steak. In food science, this reaction can be harnessed deliberately: a reducing sugar is covalently grafted onto the free amino groups of a protein, producing a protein-polysaccharide conjugate with improved solubility, antioxidant activity and interfacial behavior. The researchers chose galacto-oligosaccharides, or GOS, as their grafting partner, a prebiotic carbohydrate derived from lactose that is already valued for feeding beneficial gut bacteria. When carefully controlled, wet-heating glycosylation at 90 degrees Celsius for just 15 minutes can attach GOS to protein while avoiding the pitfalls of overdone Maillard chemistry, such as excessive browning, protein crosslinking and the formation of advanced glycation end-products.

The central insight of the study is that the history of the protein before conjugation matters as much as the conjugation step itself. The team compared two extraction routes. The conventional route used alkaline solubilization at pH 9 with stirring, precipitation at the isoelectric point and freeze-drying, yielding around 39.7 milligrams of protein per gram of flour at best. The microwave-assisted route, optimized through a nine-run screening design in a Labotron 12T system, hit its peak at 400 watts for 20 minutes at pH 9, delivering 293.72 milligrams per gram, roughly seven times the conventional yield. The rapid volumetric heating disrupts the cellular matrix and releases protein efficiently, but crucially it also appears to leave the protein in a partially unfolded state with more reactive amino groups exposed.

That conformational legacy showed up clearly in the structural data. Fourier-transform infrared spectroscopy revealed that the microwave-extracted conjugate, dubbed LPIGHM, showed the strongest evidence of carbohydrate incorporation, with a pronounced growth of the carbon-oxygen stretching envelope between 1200 and 1000 per centimeter and a weakening of the ordered amide bands. Differential scanning calorimetry and thermogravimetric analysis painted the same picture: the microwave-derived conjugate displayed the most complex thermal profile and enhanced structural integrity compared with the non-heated mixture and the conventionally prepared conjugate. Secondary-structure analysis showed beta-sheet content falling from 56.7 percent in native lupin protein to 50.0 percent in LPIGHM, with beta-turns and random coil rising in compensation, a shift from rigid order toward flexible disorder that favors interfacial performance.

Perhaps the most dramatic structural change was in particle size. Native lupin protein isolate was heavily aggregated, with a mean hydrodynamic diameter of 1775 nanometers, a figure the authors caution is skewed by a minority population of large clumps. After glycation, the conjugates shrank dramatically: 152 nanometers for the simple mixture, 99 for the conventionally prepared conjugate and 89.7 nanometers for the microwave-derived one, an apparent 19.8-fold reduction. Surface hydrophobicity collapsed in parallel, from 443 arbitrary units for the native protein to just 62.5 for LPIGHM, as hydroxyl-rich GOS chains replaced exposed apolar side chains on the particle surface. Fluorescence spectroscopy confirmed tertiary structural rearrangement, with tryptophan emission quenching and blue-shifting most strongly in the microwave-derived conjugate.

These structural shifts translated directly into functional gains. Foaming capacity of the native protein was a dismal 10 percent with 4 percent stability; the microwave-derived conjugate reached 64 percent capacity and 36 percent stability, increases of 6.4-fold and 9-fold respectively. Emulsifying activity index climbed from 7.2 to 74.2 square meters per gram, a tenfold improvement, while emulsion stability rose from 40.2 to 71.6 minutes. Water-holding capacity more than doubled to 2.9 grams per gram, and oil-holding capacity rose to 14.6 grams per gram. Solubility at neutral pH improved only modestly, from 31.5 to 33 percent, which the authors attribute to measuring well away from the isoelectric region where glycation exerts its largest effect on plant proteins.

Correlation analysis across the four treatment means reinforced the mechanistic story. The apparent degree of grafting, measured by the loss of free amino groups, was the strongest single predictor of performance, correlating at r = 0.99 with foaming capacity and r = 0.98 with emulsifying activity. Surface hydrophobicity correlated negatively with solubility and interfacial function, and particle size and beta-sheet content tracked negatively with emulsion stability. Notably, zeta potential showed no strong association with any interfacial property, supporting the authors’ argument that stabilization in these conjugates is steric and hydration-driven rather than electrostatic: the attached carbohydrate layer displaces the shear plane outward and screens the underlying charges, so a less negative zeta potential can coexist with more bound sugar and better stability.

The biological results were more nuanced and enzyme-specific. Alpha-glucosidase inhibition improved roughly fourfold in all GOS-containing systems, reaching 60 to 66 percent at 100 milligrams per milliliter, an effect present even in the non-heated mixture, suggesting the oligosaccharide itself contributes to binding at the enzyme’s pocket-shaped active site. Alpha-amylase inhibition, by contrast, was not improved and declined at low concentrations, plausibly because the hydrated sugar chains obstruct the enzyme’s extended substrate-binding cleft. ACE inhibition remained modest throughout. Antioxidant activity rose in an assay-dependent fashion: the microwave-derived conjugate excelled at ABTS radical scavenging, reaching 43.9 percent at the lowest tested concentration versus 12.8 percent for native protein, while the conventionally prepared conjugate showed the strongest reducing power and total antioxidant capacity. Against Caco-2 colorectal cancer cells, antiproliferative activity was substantial, though the native protein was the most active at 86.2 percent, and the microwave-derived conjugate partially preserved activity after heating.

The gut microbiota experiments provided the study’s most forward-looking results. Using pooled fecal slurries from six healthy adult donors in an in vitro fermentation model, the team found that the conjugates, particularly the microwave-derived one, produced the most gas, retained more acetate at 24 hours than the free GOS mixture, and fostered the most even microbial community, with a Shannon index of 3.23 versus 1.85 for the untreated control. Beneficial genera such as Bifidobacterium and Lactobacillus were enriched while opportunistic taxa including Escherichia and Klebsiella declined. PICRUSt2 functional prediction pointed to enhanced carbohydrate and energy metabolism pathways. The authors are careful to note that short-chain fatty acid concentrations declined over the incubation rather than accumulating, that the fermentation was run without simulated digestion, and that the predicted pathways reflect metabolic potential rather than measured activity.

The study’s limitations are candidly acknowledged. The design did not include a microwave-extracted protein carried through without conjugation, so the effects attributed to LPIGHM belong to the combined process rather than to microwave extraction alone. The degree of grafting is an apparent value that cannot distinguish sugar attachment from conformational masking of amino groups, and the correlation analysis rests on only four treatment means. Confirming the full picture will require mass-spectrometric mapping of glycation sites, quantification of advanced glycation end-products and available lysine, digestion studies before fermentation, and trials in real food matrices. Even so, the core message stands: how a plant protein is extracted shapes how well it can be engineered afterward. For food formulators wrestling with the functional shortcomings of legume proteins, the microwave is looking less like a shortcut and more like a strategic first move.

Subject of Research: Microwave-assisted extraction of lupin protein isolate to enhance Maillard glycation with galacto-oligosaccharides for improved functionality and gut fermentability

Article Title: Microwave-assisted extraction enhances wet-heating Maillard glycation of lupin protein with galacto-oligosaccharides: structural basis for improved interfacial functionality and gut fermentability

Article References: Ullah, N., Bamigbade, G., Arachchi, M. J. P., Ali, A., Kamal-Eldin, A., Zhou, F., Miao, S., & Ayyash, M. (2026). Microwave-assisted extraction enhances wet-heating Maillard glycation of lupin protein with galacto-oligosaccharides: structural basis for improved interfacial functionality and gut fermentability. Food Chemistry: X, 39, Article 104518. https://doi.org/10.1016/j.fochx.2026.104518

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104518

Keywords: lupin protein isolate, Maillard reaction, galacto-oligosaccharides, microwave-assisted extraction, protein glycation, emulsifying properties, foaming capacity, gut microbiota, short-chain fatty acids, prebiotics, plant protein, Food Chemistry: X