The taxonomic identity of the winning isolate deserves attention. The strain SNS1 was assigned to Priestia megaterium, a member of the large-celled Bacillus group that was reclassified into the genus Priestia following the genome-based reorganization of the family Bacillaceae. Prior to this reclassification, many of these organisms appeared in older literature as Bacillus megaterium, and a considerable body of PHA research was conducted on strains now understood to belong to this broader clade. Priestia megaterium has a long history as a biotechnological workhorse, valued for its large cell size, plasmid compatibility, and capacity to accumulate intracellular storage granules. Its ability to convert molasses sugars into poly(3-hydroxybutyrate) aligns with the metabolic profile of the group: these bacteria deploy the canonical PHA biosynthesis pathway, in which two acetyl-CoA molecules are condensed to acetoacetyl-CoA and then reduced to the hydroxybutyrate monomer that is polymerized into granules visible under the microscope. The accumulation of these granules serves as a carbon and energy sink when nitrogen or phosphorus becomes limiting, which is precisely the physiological state that fermentation engineers aim to induce.

The optimization strategy reported in the study illustrates why statistical experimental design has become standard practice in bioprocess development. Traditional one-factor-at-a-time experiments examine each variable in isolation, but fermentation outputs such as PHA yield emerge from interactions among carbon concentration, nitrogen availability, pH, temperature, agitation, and cultivation time. The Plackett-Burman design, a fractional factorial screening method, allows many variables to be tested simultaneously with a minimal number of runs, identifying which factors exert statistically significant influence on the response. In this case, the design converged on a specific combination: six percent sugar beet molasses as the carbon source, ammonium oxalate at half a gram per liter as the nitrogen source, an alkaline pH of 8.5, incubation at 37 degrees Celsius, agitation at 200 revolutions per minute, and a 24-hour cultivation period. The resulting polymer concentration of 4.79 grams per liter is notable for the short cultivation window. Many published PHA fermentations require 48 to 72 hours to reach comparable titers, so a productive 24-hour process reduces energy consumption per batch and increases the theoretical throughput of existing equipment.

The choice of ammonium oxalate as the nitrogen source is an interesting detail. Nitrogen limitation is the classical trigger for PHA accumulation, because when nitrogen becomes scarce, protein synthesis and cell division slow down while excess carbon is diverted into storage polymers. However, the identity of the nitrogen source matters: some nitrogen salts alter medium pH during consumption, and oxalate salts are relatively inexpensive and benign compared with more commonly used ammonium sulfate or ammonium chloride. The alkaline setpoint of pH 8.5 is also worth noting, since many PHA-producing bacteria prefer neutral to slightly alkaline conditions, and pH control at the upper end of the tolerance range can suppress contaminating organisms in non-sterile or minimally sterilized processes, an advantage when the goal is low-cost production.

Chemical confirmation of the polymer’s identity relied on a complementary suite of analytical techniques, each providing independent evidence. Fourier-transform infrared spectroscopy detects the characteristic ester carbonyl absorption near 1720 wavenumbers and the C-O-C stretching bands that define polyester backbones. Proton and carbon-13 nuclear magnetic resonance spectroscopy resolve the specific chemical environments of the methyl, methylene, and methine protons and carbons of the 3-hydroxybutyrate repeat unit, distinguishing P3HB from copolymers containing longer-chain hydroxyalkanoate monomers. Gas chromatography-mass spectrometry, typically performed on the methanolysis products of the polymer, quantifies the monomer composition with high specificity. When all four techniques agree, as they did here, the conclusion that the molasses-grown polymer is the homopolymer P3HB is well supported. This matters commercially because homopolymer P3HB has different material properties from the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate): P3HB is stiffer and more brittle, with a higher melting temperature, while copolymers are more flexible and easier to process by melt techniques such as extrusion and injection molding.

The thermal analyses reported in the study reinforce the structural assignment. Differential scanning calorimetry measures the melting temperature and the heat of fusion, values that for P3HB fall in a well-characterized range near 175 degrees Celsius for the melting peak, and the observed thermal transitions consistent with pure P3HB indicate that the molasses substrate did not introduce unusual monomer impurities into the polymer chain. Thermogravimetric analysis, which tracks mass loss as the sample is heated, provides information on thermal stability and degradation onset, parameters that determine whether a polymer can survive melt processing without significant chain scission. Together, these measurements give processors a first indication of how the material would behave in industrial equipment.

Perhaps the most unexpected finding is the ultraviolet-shielding behavior of the purified polymer sheet. The researchers measured an ultraviolet-shielding factor of 15.23, corresponding to roughly 35 percent absorption of incident ultraviolet light. This property is not commonly reported for neat P3HB films, and its origin may lie in the polymer’s aromatic-free but carbonyl-rich structure, which absorbs weakly in the UV-B and UV-C regions, or in residual chromophores carried over from the molasses substrate or introduced during extraction. The authors frame this as a potential sun-protective application, drawing on the established spectrophotometric methods used to determine sun protection factors in cosmetic science. While a shielding factor of 15 is modest compared with formulated sunscreens, which routinely achieve factors of 30 or higher through combinations of organic and inorganic filters, the finding suggests that PHA films or coatings could contribute ultraviolet attenuation in packaging, agricultural films, or composite materials without added synthetic UV absorbers. The reference to ocular ultraviolet protection in the cited literature hints that eyewear or lens coatings might also be contemplated, though such applications would require extensive additional validation.

Placed in a broader context, the study contributes to a growing body of work demonstrating that Priestia and related Bacillaceae can produce PHA from agricultural and food-industry residues. Previous reports from overlapping research groups have documented PHA production from sugarcane molasses, cheese whey, glycerol, and vinasse, each substrate carrying its own sugar profile and inhibitor load. Sugar beet molasses differs from cane molasses in having a higher sucrose content and lower levels of certain phenolic inhibitors, which may explain why beet molasses supports efficient growth with minimal pretreatment. The economic logic is compelling: molasses is often priced at a fraction of the cost of refined sugars, and diverting it to bioplastic production avoids competition with food uses while giving sugar mills an additional revenue stream for a byproduct that might otherwise be sold at low value as animal feed.

Several challenges remain before such a process could scale. Recovery of PHA from bacterial cells typically requires cell disruption and solvent extraction, both of which carry cost and environmental burdens unless greener solvents or enzymatic lysis methods are employed. The mechanical properties of P3HB, particularly its brittleness and narrow processing window, may require blending or plasticization for consumer applications. Consistency of molasses composition between harvests and factories could introduce variability in fermentation performance, demanding adaptive process control. And the ultraviolet-shielding claim, while intriguing, rests on a single measurement that would need replication across film thicknesses, formulations, and aging conditions. Nevertheless, the combination of a cheap substrate, a fast fermentation, a well-characterized polymer product, and an unexpected functional property makes this work a useful data point in the ongoing effort to bring microbial bioplastics closer to economic viability, and it underscores the value of systematically screening local microbial biodiversity for organisms suited to regional waste streams.

Subject of Research: Optimized production of polyhydroxyalkanoates from Priestia megaterium using sugar beet molasses: a cost-effective approach for eco-friendly bioplastics

Article Title: Optimized production of polyhydroxyalkanoates from Priestia megaterium using sugar beet molasses: a cost-effective approach for eco-friendly bioplastics

Article References: Khattab, A. M., Esmael, M. E., Elkhouly, H. I., Khashaba, R. A., Zohri, A.-N. A., El-Dean, A. M. K., Abou-Dobara, M. I., Bakr, M. M. N., Sofy, M. R., & Ibrahim, M. I. A. (2026). Optimized production of polyhydroxyalkanoates from Priestia megaterium using sugar beet molasses: a cost-effective approach for eco-friendly bioplastics. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-026-38285-8

Image Credits: AI Generated

DOI: 10.1007/s11356-026-38285-8

Keywords: Optimized, production, polyhydroxyalkanoates, Priestia, megaterium, sugar, beet, molasses, cost-effective, approach, eco-friendly, bioplastics

Microdialysis itself deserves attention as a method, because it differs fundamentally from faster imaging techniques that dominate contemporary neuroscience reporting. A fine probe with a semipermeable membrane is lowered into the target region, and artificial cerebrospinal fluid perfuses slowly through it, collecting molecules that diffuse inward from the extracellular space. The collected samples are then quantified with high-performance liquid chromatography coupled to electrochemical detection, a technique well suited to small, electroactive molecules such as dopamine and, with appropriate enzymatic steps, acetylcholine. The temporal resolution is on the order of minutes rather than milliseconds, which means the measurements reflect sustained changes in tonic signaling rather than the brief phasic bursts that individual neurons fire. Nevertheless, these slower signals are physiologically meaningful, because tonic extracellular dopamine shapes the overall excitability of medium spiny neurons and sets the gain on how subsequent phasic events are interpreted. The choice to sample during actual consumption rather than during passive infusion preserves the natural coordination of taste, smell, swallowing, and postingestive feedback that accompanies real eating behavior.

The divergent patterns observed across the three familiarity groups illustrate a principle that reward researchers have increasingly emphasized: the response of the mesolimbic system to a stimulus is not fixed but depends on the animal’s history with that stimulus. Novel sucrose produced a robust and prolonged elevation of acetylcholine in the shell, persisting even after the sugar was removed, which is consistent with the idea that cholinergic interneurons flag salient or unexpected events for further processing. These interneurons, though numbering only a small fraction of the neurons in the striatum, exert outsized influence through their widespread axonal arbors and their capacity to modulate dopamine release via nicotinic receptors located on dopaminergic terminals. When acetylcholine surges in this way, it can promote the kind of attentional sharpening that helps an animal encode the features of a new food, including any aversive qualities that later guide avoidance. The finding that this cholinergic response is absent or even reversed after prolonged exposure suggests that the shell’s internal circuitry has been recalibrated by experience, so that a once-salient flavor no longer commands the same attentional resources.

The dopamine results add an important nuance to the familiar narrative that sugar simply drives dopamine upward. In the mildly familiarized group, dopamine rose during consumption, matching the classical picture of palatable food engaging mesolimbic transmission. Yet in the novel group, no such increase appeared, and in the highly familiarized group the response was likewise absent. This inverted pattern, with the strongest dopaminergic activation occurring at intermediate familiarity, echoes the reward prediction error framework in which dopamine neurons respond most vigorously when outcomes exceed expectations. A completely novel taste may be too ambiguous to generate a confident prediction, whereas a taste experienced once or twice now carries a positive expectation that is fulfilled upon consumption, producing a prediction error signal. After two weeks of continuous access, the sugar has presumably lost its capacity to generate such errors, because its value is fully anticipated, and the dopaminergic system accordingly falls silent. This interpretation aligns with broader findings that dopamine responses habituate with repeated exposure to the same reward, even as the animal continues to consume it eagerly.

The elevated baseline acetylcholine observed in the highly familiarized group is perhaps the most intriguing finding, because it suggests a lasting change in the resting state of the shell rather than merely an altered response to the sugar itself. Elevated tonic acetylcholine could reflect compensatory upregulation following chronic stimulation, or it could indicate a shift in the balance of cholinergic tone that alters how the shell processes all incoming information, not just sugar-related signals. During consumption, this elevated baseline dropped, meaning the relative change from baseline was negative even though absolute levels may have remained within normal ranges. Such a decrease during consumption of a highly familiar reward could represent a release from attentional engagement, a neurochemical signature of automaticity in which the animal consumes without the deliberative processing that novel flavors require. The negative correlation between familiarity and both dopaminergic and cholinergic responsiveness implies that these two transmitter systems, though often studied separately, are functionally coupled in the shell, with cholinergic interneurons gating when dopaminergic terminals release their contents.

The behavioral consequences of these neuroadaptations may extend beyond simple habituation. Prior work from the same laboratory indicated that rats with long-term sugar experience were impaired in learning new negative consequences associated with a familiar sweet taste, a form of appetitive relearning deficit that could contribute to escalated intake in environments where sugar availability fluctuates. If the shell’s cholinergic and dopaminergic signals normally support the formation of aversive associations by marking unexpected or devalued outcomes, then the blunted signaling observed after chronic consumption would plausibly weaken that protective learning. In other words, an animal whose shell has adapted to sugar may continue to treat the familiar flavor as safe and desirable even when new information indicates otherwise, a mechanism with obvious relevance to overconsumption in humans who encounter sugar in countless familiar contexts.

Insulin signaling provides a metabolic bridge between dietary history and these neurochemical changes. Cholinergic interneurons in the striatum express insulin receptors, and insulin excites these cells while simultaneously facilitating dopamine release at dopaminergic terminals. Chronic high-calorie consumption alters circulating insulin and the sensitivity of peripheral and central tissues to it, raising the possibility that the neuroadaptations observed here are partly mediated by metabolic hormones acting directly on the shell circuitry. Evidence that insulin manipulation affects the hedonic response to glucose but not to non-nutritive sweeteners suggests a selective coupling between metabolic state and the processing of nutritive sugars, a coupling that could explain why repeated sugar exposure, with its accompanying postingestive nutrient feedback, produces stronger adaptations than mere taste familiarity alone would predict.

Several limitations frame the interpretation of these findings. The study examined adult male rats, leaving open questions about sex differences, which are well documented in both dopaminergic and cholinergic signaling and in the metabolic consequences of sugar consumption. The sugar exposure consisted of a ten percent sucrose solution available ad libitum for fourteen days, a regimen that models voluntary chronic intake but differs from the intermittent access protocols used in some addiction-modeling studies, which can produce more pronounced binge-like patterns. Microdialysis sampling in freely moving animals necessarily involves habituation to the testing chambers, and although the investigators took care to habituate animals before sampling, the chamber environment itself differs from the home cage in ways that could influence baseline transmitter levels. Finally, extracellular measurements cannot distinguish among the multiple cellular sources contributing to the sampled signal, including dopaminergic terminals from the ventral tegmental area, cholinergic interneurons within the shell, and modulatory inputs from the prefrontal cortex, amygdala, and hippocampus that converge on this region.

Looking forward, these results suggest several productive avenues. Directly manipulating cholinergic receptors in the shell during sugar consumption could test whether the cholinergic decline after chronic exposure is causally involved in impaired aversive learning or merely a correlate. Comparing the shell with the core in the same animals would clarify how these neighboring subregions divide the labor of reward processing across familiarity levels. Extending the approach to females and to different sugar exposure patterns would establish the generality of the findings. And because the shell participates in memory formation for hedonic stimuli, examining how chronic sugar alters other forms of learning that depend on this region, including context-based associations and outcome devaluation, would reveal whether the neuroadaptations observed here represent a narrow tuning to sugar or a broader change in how the shell encodes value. The demonstration that prolonged consumption reshapes the neurochemical landscape of a key reward region in ways that negatively correlate with stimulus familiarity provides a concrete neurobiological foundation for understanding why dietary habits become entrenched and why familiar palatable foods can be so difficult to moderate once they have become a routine part of daily life.

Subject of Research: Long-term sugar consumption alters extracellular dopamine and acetylcholine levels in the nucleus accumbens shell

Article Title: Long-term sugar consumption alters extracellular dopamine and acetylcholine levels in the nucleus accumbens shell

Article References: Vera-Rivera, G., Olvera, M. J., & Miranda, M. I. (2026). Long-term sugar consumption alters extracellular dopamine and acetylcholine levels in the nucleus accumbens shell. Frontiers in Behavioral Neuroscience, 20, Article 1938066. https://doi.org/10.3389/fnbeh.2026.1938066

Image Credits: AI Generated

DOI: 10.3389/fnbeh.2026.1938066

Keywords: Long-term, sugar, consumption, alters, extracellular, dopamine, acetylcholine, levels, nucleus, accumbens, shell, scientific research

The research focused on one of the most medically vulnerable populations in oncology: patients with blood cancers undergoing allogeneic hematopoietic cell transplantation. In this intensive procedure, patients receive high-dose chemotherapy, sometimes combined with radiation, to destroy their immune systems before donor stem cells are introduced to rebuild them. These individuals spend weeks in the hospital and are routinely given antibiotics to prevent and treat infections during the period when their defenses are essentially wiped out. Eighty percent of the patients in the study received at least one broad-spectrum antibiotic, the class of drugs that exerts the strongest impact on the microbiome because it targets many types of bacteria at once, obliterating beneficial organisms along with dangerous ones.

Antibiotics are, of course, lifesaving tools, but their broad activity comes at a cost. By indiscriminately killing bacteria, they can hollow out the gut’s ecological diversity, creating space for opportunistic pathogens to flourish. Microbiome diversity is widely regarded as a key indicator of gut health, and its loss has previously been linked with poorer clinical outcomes in patients with cancer. Preserving that diversity, the new study suggests, may be within patients’ control through something as ordinary as their meal choices.

What sets this investigation apart from most nutrition research is the extraordinary granularity of its dietary data. Over five years, the research team tracked 9,419 meals eaten by 173 hospitalized patients. Every time a patient ordered a meal from the hospital kitchen, the tray arrived with a questionnaire asking them to record how much of each item they ate and drank. By combining these real-time records with the kitchen’s nutritional information, the scientists catalogued more than 40,000 individual food items. For each patient, the team followed between eight and 128 meals across a window stretching from 12 days before transplantation to 49 days after. In parallel, they profiled microbiome diversity in more than 1,000 stool samples from 158 patients.

Marcel van den Brink, M.D., Ph.D., co-senior author of the study and president of City of Hope Los Angeles and City of Hope chief physician executive, emphasized how unusual this dataset is. Unlike past nutrition studies that depend on patients’ recollections of what they ate or on other imprecise surveys, his team worked with meticulous dietary records collected in real time, a level of detail that allowed them to detect patterns that would otherwise be impossible to see. Van den Brink, a globally recognized leader in microbiome research, cell transplantation and cancer immunotherapy, collaborated with Jonathan Peled, M.D., Ph.D., of Memorial Sloan Kettering Cancer Center and Jonas Schluter, Ph.D., of NYU’s Grossman School of Medicine.

Armed with this data, the researchers deployed a battery of advanced statistical models to search for dietary patterns associated with injury to the gut microbiome. The signal that emerged was strikingly consistent. No matter how the team analyzed the data, the same result kept appearing: patients who consumed more sweets while taking antibiotics were more likely to experience a loss of microbiome diversity as aggressive microbes crowded out other strains of bacteria. One organism in particular stood out, Enterococcus, a bacterium whose domination of the gut is associated with a higher risk of bloodstream infections, graft-versus-host disease and other life-threatening complications in transplant patients.

The magnitude of the effect was substantial. The combination of high-sugar foods and broad-spectrum antibiotics appeared to multiply the damage to the microbiome, producing a 24 percent drop in bacterial diversity for every 100-gram increase in sweets consumed, an amount of sugar roughly equivalent to a large milkshake. In other words, the dietary factor did not merely add to antibiotic-induced injury; it appeared to interact with it, deepening the ecological collapse that broad-spectrum drugs alone can trigger.

To test whether the association reflected a genuine biological mechanism rather than a statistical coincidence, the researchers turned to animal models. They gave broad-spectrum antibiotics to healthy mice and fed the animals a variety of diets. Mice eating a high-sucrose diet rapidly developed an overgrowth of Enterococcus in their guts, mirroring the pattern seen in the hospitalized patients. Critically, mice that ate the high-sugar diet without receiving antibiotics maintained normal bacterial diversity, indicating that sugar alone was not the culprit; rather, it was the combination of sugar and antibiotics that proved destructive. Van den Brink noted that the convergence of animal studies with the patient data provides a compelling rationale for future clinical trials to evaluate whether reducing sugar intake during antibiotic use would protect the microbiome.

The implications extend well beyond the transplant ward. The microbiome is increasingly recognized as an important factor in cancer care, influencing how patients respond to therapy and how they recover from it, and the better clinicians understand what supports or disrupts it, the more opportunities they have to reduce treatment side effects. For hospitalized cancer patients, diet represents one of the most practical levers hospitals can pull to support recovery. Van den Brink pointed out an uncomfortable irony in current clinical practice: many of the foods and drinks that hospitals encourage patients to consume, including nutritional shakes, smoothies and sports drinks, are high in sugar, something he said will need to be re-evaluated when prescribing antibiotics.

The study also reframes the concept of antibiotic stewardship. Traditionally, stewardship has focused on limiting antibiotic use to prevent the emergence of resistance, but the new findings suggest it should also encompass how different antibiotics affect the microbiome, since some disrupt beneficial gut bacteria far more than others. Van den Brink encourages patients to ask their healthcare teams to ensure that antibiotics are thoughtfully chosen from equally effective treatment options for controlling infections. As for whether people on antibiotics should simply cut out sugar, he counsels a measured approach. It is premature, he said, to recommend that everyone taking antibiotics avoid sugar, but he also observed that there is no strong evidence that probiotics help preserve or restore microbiome diversity, even though many people take them anyway. Limiting sugar, by contrast, carries no known harm and is an easy thing to try. The work was supported by the National Cancer Institute, the National Heart, Lung and Blood Institute, and the Susan and Peter Solomon Microbiome, Nutrition and Cancer Program at Memorial Sloan Kettering Cancer Center, and it reinforces a growing movement in medicine to treat food not merely as fuel but as an active component of therapeutic care.

Subject of Research: The interaction between dietary sugar and antibiotics in disrupting gut microbiome diversity in cancer patients undergoing stem cell transplantation

Article Title: Study suggests skipping sweets during antibiotic treatment may help protect the gut microbiome

Article References: Study suggests skipping sweets during antibiotic treatment may help protect the gut microbiome. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: gut microbiome, antibiotics, sugar, stem cell transplant, microbiome diversity, Enterococcus, cancer care, nutrition, food as medicine, City of Hope, Nature, antibiotic stewardship

The review, conducted by Margarida Bica, Jessica Renzella, Asha Kaur and Mike Rayner of the University of Oxford, drew on both peer-reviewed literature and the often-overlooked grey literature of government regulations, technical manuals and policy documents. The researchers systematically searched for nutrient profile models specifically developed or applied to front-of-pack nutrition labelling systems, characterising each model according to the type of labelling scheme it supported, the nutrients and food components it restricted or encouraged, and the evidence of its scientific validation. The scope matters, the authors argue, because the sheer proliferation of NPMs now poses a practical challenge for policymakers: with dozens of options available, choosing an appropriate model for a national labelling policy has become a non-trivial scientific and political decision.

The taxonomy that emerged from the analysis mirrors the main families of front-of-pack labelling in use today. Fifteen of the 42 identified models were developed for warning-label schemes, the approach pioneered in Chile and now dominant across much of Latin America, in which products exceeding thresholds for nutrients of concern carry prominent black octagons declaring them high in sugar, sodium or saturated fat. Eleven models underpinned nutrient-specific systems, including the traffic-light labelling familiar to British shoppers, which displays colour-coded indicators for individual nutrients. Another 11 models supported health endorsement schemes, such as the Nordic Keyhole or Singapore’s Healthier Choice Symbol, which positively certify foods deemed healthier choices. Four models drove summary scores, exemplified by France’s Nutri-Score and Australia’s Health Star Rating, which condense a food’s overall nutritional quality into a single graded mark. One model served other system types.

Beneath this structural variety, the review found striking common ground on which nutrients matter most. Every one of the 42 models limited the content of sugar, reflecting the strength of the scientific evidence linking excess sugar intake to obesity, type 2 diabetes and dental disease. The vast majority also placed restrictions on sodium and saturated fat, the two other nutrients most consistently associated with non-communicable disease burden. This convergence suggests that, despite institutional and regional differences, the underlying nutritional science has produced a broadly shared view of which dietary components should trigger concern on the front of a package. Sweeteners, energy density, protein, fibre, fruit and vegetable content appeared in more variable combinations across models, reflecting differing philosophies about whether labels should simply flag harmful nutrients or also reward beneficial ones.

Where the consensus frays is in the details of implementation. Thresholds for what counts as high in sugar differ between models; some assess nutrients per 100 grams while others evaluate them per serving or as a proportion of total energy; category-specific rules treat staples such as cheese, oils and beverages differently across schemes. The review documents this heterogeneity in granular detail, showing that two products judged unhealthy under one national scheme may pass cleanly under another. For multinational food manufacturers, this patchwork creates compliance complexity and, critics argue, opportunities to formulate products to game particular algorithms. For policymakers in countries drafting their first labelling laws, the absence of a single validated standard complicates decisions that industry lobbyists are often eager to influence.

Validation emerged as another significant gap. The review assessed whether models had demonstrated convergent validity, meaning agreement with other established measures of nutritional quality, and criterion validity, meaning the ability to predict health-relevant outcomes. Convergent validity was demonstrated for nine of the 42 models, while criterion validity was shown for only three. In other words, the scientific evidence underpinning most front-of-pack labelling algorithms remains thin relative to their policy importance. The authors note that this imbalance reinforces the need for greater regional guidance and alignment, so that new labelling programmes can build on models whose performance has been rigorously tested rather than reinventing criteria from scratch under political pressure.

The policy stakes are considerable. Diet-related non-communicable diseases, including cardiovascular disease, diabetes and several cancers, are among the leading causes of death globally, and governments increasingly view front-of-pack labels as a fast, low-cost intervention that shifts both consumer choice and industry reformulation. Chile’s warning-label law, implemented in stages since 2016, has been associated with reductions in purchases of sugary drinks and prompted widespread product reformulation across the region. The Pan American Health Organization’s nutrient profile model has served as a regional benchmark, while the World Health Organization has issued guiding principles and framework manuals to support member states. The European Union is weighing a harmonised mandatory front-of-pack label, a debate in which the choice between Nutri-Score-style summary scores and other approaches has become intensely contested among member states, scientists and industry groups.

The review also situates nutrient profiling within a broader scientific conversation about what food labels should measure. A growing body of research argues that nutrient-based models, however well calibrated, fail to capture the degree of industrial processing, exemplified by the NOVA classification of ultra-processed foods, which has been independently associated with adverse health outcomes in large cohort studies. Recent work has explored modifying established algorithms, such as Australia’s Health Star Rating, to account for ultra-processing, and examining the complementarity between updated Nutri-Score criteria and NOVA categories. The Oxford review does not resolve this debate, but its systematic inventory provides the evidentiary scaffolding for it, documenting precisely which models exist, what they measure and where their validation evidence stands.

Methodologically, the review followed established systematic review practice, including structured searches across peer-reviewed databases and targeted collection of grey-literature policy documents from national ministries, regional health bodies and regulatory agencies across the Americas, Europe, Asia, Africa and the Eastern Mediterranean. The authors screened studies collaboratively, analysed model characteristics in detail and reported their findings with extensive supplementary tables. The inclusion of grey literature proved essential: many of the 42 models, particularly those embedded in national regulations from Chile and Mexico to Kenya, Samoa and the Gulf states, exist primarily in legal texts and technical manuals rather than scientific journals. Without such searches, the true global diversity of nutrient profiling for labelling would be substantially underestimated.

The review’s central message is ultimately one of opportunity tempered by fragmentation. Front-of-pack nutrition labelling has matured from a handful of voluntary schemes into a global policy movement with real evidence of impact, and the raw material for that movement, a library of 42 nutrient profile models, is now catalogued and characterised. But the heterogeneity the authors document suggests that the field has not yet converged on what constitutes the most appropriate model for labelling purposes, and that validation evidence lags behind deployment. Greater regional guidance and alignment, the authors conclude, would help countries adopt models with demonstrated performance, reduce industry gaming of inconsistent thresholds, and move the world’s food packages toward labels that are not only eye-catching but scientifically defensible. As more governments prepare to legislate, the choice of algorithm beneath the label may prove as consequential as the label itself.

Subject of Research: Nutrient profile models developed and used for front-of-pack nutrition labelling systems to classify foods and support policies against diet-related non-communicable diseases.

Article Title: Systematic review of nutrient profile models for front-of-pack nutrition labelling

Article References: Bica, M., Renzella, J., Kaur, A., & Rayner, M. (2026). Systematic review of nutrient profile models for front-of-pack nutrition labelling. Nature Food. https://doi.org/10.1038/s43016-026-01414-0

Image Credits: AI Generated

DOI: 10.1038/s43016-026-01414-0

Keywords: nutrient profile models, front-of-pack nutrition labelling, food policy, non-communicable diseases, sugar, sodium, saturated fat, warning labels, Nutri-Score, traffic-light labelling, systematic review, public health nutrition