The research drew on residual blood samples collected during the 2019 endline survey of the FAARM trial, a cluster-randomized study conducted in rural Bangladesh. In total, 719 participants—433 women and 286 children—were included in the investigation. The team, led by Nicholas N. A. Kyei of the Institute of Public Health at Charité – Universitätsmedizin Berlin together with colleagues at Heidelberg University, the Potsdam Institute for Climate Impact Research, and the Institute of Food Chemistry at Universität Münster, analyzed 712 whole blood and 578 serum samples using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry, or UHPLC-MS/MS. This technique can detect and quantify multiple fungal toxins and their metabolites at vanishingly low concentrations, making it the gold standard for human biomonitoring of mycotoxins.

The starkest result concerned ochratoxin A, a nephrotoxic and possibly carcinogenic mycotoxin produced by Aspergillus and Penicillium fungi that frequently contaminates cereals, spices, and dried fruit. OTA was detected in 100 percent of whole blood samples, and its lesser-known isomer, 2′R-ochratoxin A, appeared in 98 percent. Citrinin, a toxin produced by the same fungi and known to damage the kidneys, was found in 91 percent of samples, while Enniatin B, an emerging mycotoxin with antimicrobial and cytotoxic properties, was present in 92 percent. Beauvericin, another emerging toxin, was detected in 6 percent of samples. The sheer ubiquity of these compounds in human blood underscores how difficult it is to avoid mycotoxin exposure where contaminated staple foods form the daily diet.

Perhaps the most consequential finding involved aflatoxin B1, one of the most potent liver carcinogens known to science. Because AFB1 itself is rapidly metabolized, researchers instead measured AFB1-lysine adducts—molecules formed when the toxin’s reactive metabolite binds covalently to the blood protein albumin. Serum samples were enzymatically digested and cleaned up by solid-phase extraction before analysis. The adduct, a biomarker of chronic exposure over the preceding two to three months, was detected in nearly one-quarter of the women and 4 percent of the children with serum samples. Chronic aflatoxin exposure is linked to liver cancer, immune suppression, and child growth impairment, so its presence in a substantial fraction of reproductive-age women is a serious public health signal.

To translate blood concentrations into estimates of actual intake, the team calculated the probable daily intake, or PDI, for the most frequently detected toxins using toxicokinetic-based approaches. The results were alarming. The PDI of ochratoxin A exceeded health-based guidance values in 80 percent of the women and a striking 99 percent of the children. Citrinin intake was of concern for 12 percent of women and 27 percent of children. Children, with their lower body weight and developing organs, emerged as the most vulnerable group, absorbing comparable toxin burdens through smaller bodies and facing proportionally higher risks.

The study’s co-exposure findings add another layer of concern. Toxicology has traditionally assessed chemicals one at a time, yet mycotoxins frequently co-occur on the same food items because the fungi that produce them thrive under similar conditions of humidity, poor storage, and inadequate drying. OTA and citrinin, for instance, are often produced together by the same fungal species, and their combined kidney toxicity may be greater than either alone. With every participant carrying at least two mycotoxins and most carrying three or more, the realistic exposure scenario in rural Bangladesh is a complex toxicological cocktail whose interactions remain poorly understood.

Why is exposure so pervasive? In rural Bangladesh, maize, rice, wheat, and groundnuts are dietary staples, and these crops are highly susceptible to fungal contamination in the country’s hot, humid climate. Smallholder households often lack access to proper drying facilities, hermetic storage, or the means to sort and discard moldy grain. Food safety regulations, where they exist, are difficult to enforce in informal markets. As a result, mycotoxins enter the food supply at the farm level and travel directly to the family plate, with no practical means of avoidance for the households most affected.

The health implications extend beyond acute toxicity. Ochratoxin A is associated with chronic kidney disease and has been classified as possibly carcinogenic to humans. Aflatoxin B1 is a Group 1 human carcinogen that synergizes with hepatitis B infection to multiply liver cancer risk, a particularly worrying combination in regions where hepatitis B remains prevalent. Emerging toxins like enniatin B and beauvericin are only beginning to be characterized, and their long-term effects at chronic low doses are unknown. For children, chronic mycotoxin exposure has been linked in previous research to growth faltering, immune dysfunction, and reduced vaccine response—burdens that compound the already heavy challenges of malnutrition and infectious disease.

The authors emphasize that their findings demonstrate widespread co-exposure to multiple mycotoxins, with OTA, citrinin, and aflatoxin B1 posing notable risks, and they call for urgent, targeted interventions to protect vulnerable populations. Such interventions could include promoting improved post-harvest handling and drying practices, introducing hermetic storage bags that block fungal growth, supporting biocontrol agents that competitively exclude toxigenic fungi in the field, and strengthening food monitoring systems. Because blood biomonitoring captures actual internal exposure rather than estimated dietary intake, the approach used here could serve as a model for other low- and middle-income countries where mycotoxin contamination is suspected but poorly quantified.

The study also highlights the value of repurposing existing trial infrastructure for environmental health surveillance. By analyzing residual samples from the FAARM trial, the researchers obtained population-scale exposure data at a fraction of the cost of a dedicated biomonitoring campaign. As climate change expands the geographic range of toxigenic fungi and staple food systems come under increasing stress, the silent burden of mycotoxins documented in rural Bangladesh is likely a warning of what many other communities face. Making the invisible visible, this study suggests, is the first step toward reducing a health risk that has been simmering in the blood of millions for generations.

Subject of Research: Chronic blood-borne exposure to the mycotoxins aflatoxin B1, ochratoxin A, and citrinin among women and children in rural Bangladesh

Article Title: Chronic exposure to aflatoxin B1, ochratoxin A, and citrinin in women and children and associated health risk characterization: blood biomonitoring evidence from rural Bangladesh

Article References: Kyei, N. N. A., Cramer, B., Humpf, H.-U., Kuhn, M., Sobhan, S., Veerkamp, J., & Gabrysch, S. (2026). Chronic exposure to aflatoxin B1, ochratoxin A, and citrinin in women and children and associated health risk characterization: blood biomonitoring evidence from rural Bangladesh. Environmental Health, 25(1), Article 75. https://doi.org/10.1186/s12940-026-01330-7

Image Credits: AI Generated

DOI: 10.1186/s12940-026-01330-7

Keywords: mycotoxins, aflatoxin B1, ochratoxin A, citrinin, biomonitoring, Bangladesh, blood analysis, risk characterization, food safety, public health, children's health, UHPLC-MS/MS

Spleen deficiency with dampness pattern diarrhea is a diagnosis rooted in traditional Chinese medicine that overlaps substantially with chronic functional diarrhea and diarrhea-predominant irritable bowel syndrome as understood in Western medicine. In traditional medical theory, the condition arises when the digestive system loses its capacity to transform and transport fluids, producing loose stools, fatigue, poor appetite, and abdominal discomfort. Clinically, Weiling Decoction has been used for such patients for years, but the pharmacological basis of its effects has remained poorly characterized. The new study set out to close that gap by combining modern analytical chemistry with high-throughput genomic sequencing.

The research team, led by corresponding author Ying Cai, first established a mouse model of the syndrome by exposing Kunming mice to high-humidity environments and administering oral lard, a combination designed to replicate the cold, damp conditions and dietary factors associated with the disorder. The team then turned to an ultra-high-performance liquid chromatography tandem mass spectrometry workflow, known as UHPLC-MS/MS, to chemically fingerprint Weiling Decoction. This analysis identified twenty primary bioactive compounds in the formula, including vicenin-1, inosine, and chlorogenic acid, each of which has documented anti-inflammatory or metabolic activity in previous literature.

With the chemical profile in hand, the researchers evaluated how the formula performed therapeutically. Histological examinations of small intestinal tissue revealed that treated mice showed a marked restoration of villus length, the finger-like projections that absorb nutrients in the gut and are often damaged or shortened in diarrheal disease. Treated animals also exhibited a higher density of goblet cells per unit area, specialized cells that produce the protective mucus layer lining the intestinal wall. These structural changes suggest that the decoction does more than suppress symptoms; it appears to actively support the repair and maintenance of the intestinal mucosal barrier.

Biochemical assays reinforced the picture of a remedy that rebalances disrupted signaling networks. Serum levels of cyclic adenosine monophosphate, or cAMP, a molecule central to regulating fluid secretion in the gut, rose in treated mice alongside increases in D-xylose, a marker of intestinal absorptive capacity, and gastrin, a hormone that stimulates digestive function. Meanwhile, levels of cyclic guanosine monophosphate, or cGMP, and vasoactive intestinal peptide, or VIP, both of which promote intestinal secretion and can exacerbate diarrhea when overproduced, were reduced. Together these shifts indicate that the formula helps recalibrate what the researchers describe as the gastrointestinal-water-energy regulatory network, a coordinated system of hormonal and second-messenger signals that governs how the gut manages fluids and energy.

The heart of the study lies in its microbiome analysis. Using 16S rRNA gene sequencing, the researchers surveyed the bacterial populations in the small intestinal contents of the mice and found that treatment with Weiling Decoction significantly increased the relative abundance of three bacterial genera: Limosilactobacillus, Dwaynesavagella, and Paramuribaculum. Limosilactobacillus, a genus that includes well-known probiotic species, has been repeatedly linked to gut barrier protection and anti-inflammatory effects. Shifts in these bacterial populations suggest the decoction works in part by nurturing a microbial community better equipped to maintain intestinal homeostasis.

To probe what these microbial changes might mean functionally, the team applied PICRUSt2, a computational tool that predicts the metabolic capabilities of microbial communities based on their genetic profiles. The analysis pointed to secondary bile acid biosynthesis as a potentially critical mechanistic pathway. Secondary bile acids are produced when gut bacteria chemically modify the bile acids released by the liver, and a growing body of research links these microbial metabolites to intestinal immune regulation, epithelial barrier integrity, and metabolic signaling. The finding is consistent with recent work showing that gut symbionts can alleviate metabolic and inflammatory disease through secondary bile acid pathways, and it places Weiling Decoction’s effects within a rapidly expanding framework of microbiome-mediated pharmacology.

The study’s authors are careful to frame their findings as correlative rather than definitively causal, noting that the results suggest a microbiota-associated pharmacological mechanism rather than proving one outright. Direct evidence that transplanting the altered microbiota reproduces the therapeutic effect, for instance through fecal microbiota transplantation experiments, remains a logical next step. Nonetheless, the convergence of histological repair, biochemical normalization, and microbial restructuring in the same animals provides a coherent and testable model for how the formula may exert its clinical effects.

From a broader perspective, the research speaks to a growing scientific interest in what traditional Chinese medicine practitioners call syndrome-matched treatment, the idea that therapies should be tailored not just to a disease label but to the specific pattern of dysfunction an individual patient exhibits. By characterizing both the chemical constituents of Weiling Decoction and the molecular and microbial consequences of its administration, the study provides what the authors describe as a biotechnological basis for such syndrome-targeted approaches to gastrointestinal disorders. The data underlying the microbiome analysis have been deposited in the NCBI Sequence Read Archive under accession number PRJNA1346698, allowing other researchers to scrutinize and extend the findings.

Chronic diarrhea remains a substantial global health burden, and conventional treatments often manage symptoms without addressing the underlying disruptions in gut ecology and signaling that drive recurrence. If the mechanisms identified in this mouse model hold up in further studies, including controlled human trials, Weiling Decoction could offer a template for developing microbiome-directed therapies that restore gastrointestinal function by working with, rather than against, the body’s resident microbial communities. For now, the study stands as a compelling example of how modern analytical tools, from mass spectrometry to gene sequencing, can illuminate the biological logic hidden within traditional remedies and potentially translate ancient clinical wisdom into the pharmacological language of the twenty-first century.

Subject of Research: Weiling Decoction alleviates spleen deficiency with dampness pattern diarrhea through modulation of intestinal microbiota

Article Title: Integrated UHPLC–MS/MS and 16S rRNA sequencing reveals that Weiling Decoction alleviates spleen deficiency with dampness pattern diarrhea by modulating intestinal microbiota

Article References: Yu, D., Long, Q., Tian, Q., Zhang, X., Li, D., Tan, Z., & Cai, Y. (2026). Integrated UHPLC–MS/MS and 16S rRNA sequencing reveals that Weiling Decoction alleviates spleen deficiency with dampness pattern diarrhea by modulating intestinal microbiota. 3 Biotech, 16(10), Article 421. https://doi.org/10.1007/s13205-026-05052-y

Image Credits: AI Generated

DOI: 10.1007/s13205-026-05052-y

Keywords: Weiling Decoction, traditional Chinese medicine, intestinal microbiota, diarrhea, 16S rRNA sequencing, UHPLC-MS/MS, spleen deficiency with dampness pattern, secondary bile acids, gut barrier, PICRUSt2, Limosilactobacillus, gastrointestinal health