Scientific Research of Fiber Shape

CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:

CHICORY

The Effects of Chicory Inulin-Type Fructans Supplementation on Weight Management Outcomes: Systematic Review, Meta-Analysis, and Meta-Regression of Randomized Controlled Trials

Overview

Background: Chicory-derived inulin-type fructans (ITF) are a well-established prebiotic fiber known to shift the composition of the gut microbiota. This review set out to determine whether that shift translates into measurable weight management benefits in humans.

Methods: The research team systematically searched EMBASE, MEDLINE and the Cochrane Library for randomized controlled trials testing chicory-derived ITF (inulin, oligofructose, or a blend of the two) against a placebo or control in adults. They excluded studies using fructans from other plant sources (like agave or artichoke) or fructans combined with probiotics, so the results reflect chicory ITF specifically. Thirty-two eligible trials, representing 1,184 participants across four continents, were pooled using a random-effects meta-analysis. The typical trial in this pool used a daily dose around 10g for about 12 weeks, though doses and durations varied.

Results: Chicory ITF supplementation was associated with a statistically significant reduction in body weight compared to placebo, along with meaningful reductions in BMI, total fat mass, and waist circumference. Reductions in body fat percentage only reached statistical significance in trials lasting longer than 8 weeks, suggesting this particular benefit builds with sustained use rather than showing up quickly. Critically, these benefits held up regardless of whether participants were otherwise healthy or living with a metabolic condition like prediabetes or type 2 diabetes, and trials lasting more than 8 weeks consistently showed larger effects than shorter ones. The authors point to a likely mechanism: ITF is fermented by gut bacteria into short-chain fatty acids, which appear to stimulate satiety hormones like GLP-1 and PYY while suppressing the hunger hormone ghrelin — and separately, ITF consumption is known to enrich populations of Bifidobacterium and Akkermansia muciniphila, two bacteria linked to a healthier metabolic profile.

Conclusion: The researchers concluded that chicory ITF supplementation is a reasonable, evidence-supported strategy to support weight management — with benefits most pronounced when used consistently for 8 weeks or longer.

Source: Reimer RA, Theis S, Zanzer YC. "The Effects of Chicory Inulin-Type Fructans Supplementation on Weight Management Outcomes: Systematic Review, Meta-Analysis, and Meta-Regression of Randomized Controlled Trials." American Journal of Clinical Nutrition. PMID: 39313030; PMCID: PMC11600113.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11600113/

Back to the Roots: Revisiting the Use of the Fiber-Rich Cichorium intybus L. Taproots

Overview

This review from Wageningen University researchers (including Willem de Vos, one of the scientists who first identified Akkermansia muciniphila) takes a step back from isolated inulin supplements to look at the chicory taproot as a whole food — its full fiber composition, its multi-thousand-year history of use, and the current safety and regulatory picture around it.

Key findings: By dry weight, chicory root is one of the most fiber-dense vegetables ever measured — nearly 90% fiber, a mix of inulin, pectin, cellulose and hemicellulose, plus phytochemicals like sesquiterpene lactones and chlorogenic acid. The authors trace chicory's use back over 2,000 years, documented as both a food and a digestive remedy by Greek and Roman physicians, and later throughout medieval and Renaissance European medicine specifically for gastrointestinal complaints. On safety, the review reports that inulin has been tested in human trials at doses up to 50g per day without safety concerns, with the only downside being dose-dependent gas and bloating that tends to appear around 20–30g per day — well above the amount used in a typical daily supplement serving. The review also notes that European regulators (EFSA) have approved an official health claim for native chicory inulin at 12g per day specifically for supporting stool regularity, and the FDA lists chicory root inulin as Generally Recognized As Safe (GRAS).

Conclusion: The authors conclude that chicory root's fiber profile and long safety record make it a well-supported, well-tolerated way to help close the widespread "fiber gap" in modern diets, with the added benefit of naturally occurring plant compounds that isolated inulin extracts alone don't provide.

Source: Puhlmann ML, de Vos WM. "Back to the Roots: Revisiting the Use of the Fiber-Rich Cichorium intybus L. Taproots." Advances in Nutrition. PMID: 32199025; PMCID: PMC7360457.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7360457/

Chicory: Understanding the Effects and Effectors of This Functional Food

Overview

Most chicory research focuses on inulin alone, but this study looked at three other natural compounds found in whole chicory root — fructose, chlorogenic acids, and sesquiterpene lactones — to understand what else in the root might be contributing to its health effects.

Methods: Mice were fed a daily chicory root decoction, or one of the three isolated compounds, for 30 days. Researchers then analyzed gene expression changes in the liver, intestine, and gut microbiota, along with blood hormone levels. They paired these animal findings with lab-based (in vitro) tests on human liver and immune cells to see whether the same effects held up outside the body.

Results: The chicory diet was associated with gene activity changes across several categories: markers tied to inflammation control, blood sugar and lipid metabolism, appetite regulation, and antioxidant defense. In the hormone testing, one chicory compound (chlorogenic acid) was linked to lower circulating leptin, a hormone tied to fat storage, while another (sesquiterpene lactones) was linked to higher GIP, a hormone that helps stimulate insulin release. In the gut microbiota analysis, the chicory diet increased several beneficial, short-chain-fatty-acid-producing bacterial groups while decreasing bacteria more commonly associated with inflammation and fatty liver disease. In lab-based testing on human immune cells, chicory extract meaningfully reduced the release of several inflammatory signaling molecules, and separately showed measurable antioxidant activity in cell-free testing. Of the three compounds studied, fructose was linked to the largest share of these effects, with chlorogenic acids and sesquiterpene lactones each contributing more specifically to particular effects like inflammation control and antioxidant activity.

Conclusion: The researchers concluded that chicory's health benefits likely come from multiple compounds working together — not inulin alone — including effects on inflammation, gut bacteria balance, metabolism, and antioxidant protection.

Source: Pouille CL, Ouaza S, Roels E, et al. "Chicory: Understanding the Effects and Effectors of This Functional Food." Nutrients, 2022, 14(5), 957. PMID: 35267932; PMCID: PMC8912540.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8912540/

Chicory: From Nutritional and Bioactive Riches to Therapeutic Uses and Functional Applications

Overview

This is a broad review covering the full Cichorium genus (chicory), pulling together two decades of research (2005–2025) on its nutrient makeup, active compounds, and use in food, medicine, and health products across both Western and traditional Chinese/Uyghur medicine.

Key points: The review confirms chicory root and leaves are rich in inulin along with a range of other bioactive compounds — phenolic compounds, flavonoids, terpenoids, vitamins and minerals — that together contribute to antioxidant, anti-inflammatory and antimicrobial activity. The authors note chicory has a long documented history of use for digestive support, appetite stimulation, and gut microbiota health, and highlight that current commercial use is heavily concentrated on inulin extraction, while the rest of the root's bioactive compounds remain comparatively underexplored and underused. The review also points to promising but still-developing research directions for chicory in weight management, blood sugar regulation, and gut health support.

Conclusion: The authors conclude that chicory holds meaningful potential across food, health-product, and medicinal applications, but call for more research into its lesser-studied compounds and the parts of the plant (particularly the whole root) that current products tend to overlook in favor of isolated inulin.

Source: Dang W, Li Q, Wang Y, Zhou D, Chen J, Yang C, Huang L, Li N. "Chicory: From Nutritional and Bioactive Riches to Therapeutic Uses and Functional Applications." South African Journal of Botany, 2026. DOI: 10.1016/j.sajb.2026.05.002.
https://www.sciencedirect.com/science/article/abs/pii/S025462992600253X

L-GLUTAMINE

Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation

Overview

This is a comprehensive review from researchers across several universities (including Philip Newsholme, whose father's lab first identified glutamine's role in immune cell function back in the 1970s-80s) covering how the body produces, distributes, and uses glutamine — with a specific focus on the gut, liver, and immune system, plus what the clinical evidence says about supplementation.

Key findings on the gut specifically: The review describes the intestine as one of the body's largest consumers of glutamine, and notably, glutamine is quantitatively more important than glucose as an energy source for intestinal cells. Roughly 75% of the glutamine used by enterocytes (the cells lining the gut) gets converted into cellular energy, with the rest incorporated directly into cell proteins or used to build other amino acids. Mechanistically, the review describes glutamine as reducing the breakdown of enterocyte proteins by suppressing a specific protein-degradation pathway, and as activating cell-signaling pathways tied to cell proliferation and tissue repair in the gut lining. Under stress conditions, glutamine deficiency was shown to worsen intestinal cell death, while adequate glutamine reduced it in a dose-dependent way. The review also cites human research finding that glutamine reduces production of several inflammatory signaling molecules (including IL-1β, IL-6, IL-8 and TNF-α) directly in human intestinal tissue.

Clinical evidence cited: Beyond mechanism, the review references real clinical trial data: in a systematic review of 15 studies in cancer patients, oral glutamine supplementation (doses ranging from about 7.5g up to 30g per day) significantly reduced treatment-related mucositis in the majority of trials. In one double-blind, placebo-controlled randomized trial specifically, colorectal cancer patients given 18g of glutamine daily saw reduced chemotherapy-related diarrhea and improved intestinal absorption and permeability.

Conclusion: The authors conclude that glutamine plays a well-established, mechanistically clear role in maintaining gut lining integrity and immune cell function, and is considered safe as a standalone supplement — though they note that not everyone benefits equally, and that supplementation is most clearly indicated in situations of high physical stress (illness, surgery, intense exercise) rather than as a universal requirement for healthy, well-nourished individuals.

Source: Cruzat V, Rogero MM, Keane KN, Curi R, Newsholme P. "Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation." Nutrients, 2018, 10(11), 1564. PMID: 30360490; PMCID: PMC6266414.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6266414/

Glutamine Supplementation and Exercise: A Narrative Review of Biochemical Mechanisms and Timing Strategies

Overview

This 2026 review from researchers at the University of Nis (Serbia) is a rigorous, well-documented narrative review — not a full systematic review, but with a clearly described literature search (84 initial results, screened down to 23 clinical trials and 10 preclinical studies spanning 2015–2025). It focuses specifically on glutamine's role during exercise-induced stress, including its effect on gut lining integrity, which is the most directly relevant piece for Fiber Shape.

Key mechanism: The review confirms that enterocytes (the cells lining the gut) rely heavily on glutamine as fuel, and that glutamine helps preserve "tight junctions" — the protein connections between intestinal cells that control what does and doesn't pass through the gut lining. Physical stress (in this case, intense exercise) can disrupt these tight junctions and increase intestinal permeability; the review frames glutamine as a nutrient that may help protect against that disruption.

What the actual human trials found: This is where the picture gets nuanced. Results across the 23 clinical trials were genuinely mixed:

• Several trials found real benefits: one study found a dose-dependent decrease in intestinal permeability and gut-injury markers after glutamine, given before exercise in heat; another found reduced intestinal permeability with a 6-day glutamine-and-cystine combination; a third found glutamine reduced oxidative stress markers and restored glutathione levels over 14 days.
• But other trials found the opposite or nothing: one study found a single dose of glutamine before exercise increased intestinal permeability in healthy adults; another found no measurable effect on gut injury markers in trained cyclists at all.
• Across the full set of studies, the review is explicit that "findings are inconsistent" and that glutamine "does not consistently improve performance outcomes."

Dosing and safety data (useful and directly relevant): Across the trials reviewed, doses ranged from 0.6g to 20g per day (or 0.15–0.9g per kg of body weight). The review cites a formal risk-assessment analysis identifying 14g per day as the upper safe long-term intake level for healthy adults, and notes doses of 0.3–0.6g/kg are well tolerated, while higher single doses (0.9g/kg) can cause mild GI discomfort like nausea.

Conclusion: The authors conclude that glutamine is "biologically plausible" as a supportive nutrient for gut integrity and recovery, but that current evidence is too inconsistent to make firm recommendations, and that routine supplementation for performance specifically "appears not to be justified" based on current data.

Source: Djordjevic B, Stojiljkovic V, Velickov A, et al. "Glutamine Supplementation and Exercise: A Narrative Review of Biochemical Mechanisms and Timing Strategies." Medicina, 2026, 62(2), 329. DOI: 10.3390/medicina62020329.
https://www.mdpi.com/1648-9144/62/2/329

APPLE PECTIN

Nutrition and Health Effects of Pectin: A Systematic Scoping Review of Human Intervention Studies

Overview

This is a large, well-conducted scoping review that mapped the entire 60+ year history of human research on pectin — 134 separate studies from 1961 to 2022, across gut health, blood sugar, cholesterol, mineral absorption, and immune function. It's a good source for understanding the overall shape of the evidence, though as a scoping review it summarizes what exists rather than pooling results into a single statistical answer the way a meta-analysis does.

Gut health findings: Across 50 studies, pectin was generally well tolerated even at high doses, with the main side effect being mild, transient gas or bloating — the same as most fibers — that typically resolved within a few days as people adjusted. Notably, several studies found that in more vulnerable populations (hospitalized patients on tube feeding, children with reflux), adding pectin actually reduced digestive symptoms like reflux and diarrhea. In healthy adults specifically, though, the review found pectin had limited impact on stool frequency or transit time — its most consistent healthy-adult gut benefit was slowing gastric emptying and increasing fullness, not necessarily "regularity" in the laxative sense.

Cholesterol findings (the strongest, most established benefit): This is where the evidence is most solid. The review confirms that EFSA (the European food safety regulator) has approved an official claim that pectin helps maintain normal blood cholesterol, based on a "cause-and-effect relationship" established across multiple trials — at a minimum dose of 6g per day. Twenty-eight of 34 studies on fat metabolism found pectin lowered cholesterol, and the effect appears to depend on pectin's molecular structure: higher-molecular-weight, higher-esterification pectin (which describes both citrus and apple pectin specifically) worked better than lower-grade versions.

Blood sugar and satiety findings: Also well-established. EFSA has separately approved a claim that pectin reduces the post-meal blood sugar spike, based on a minimum of 10g per meal. Mechanistically, the review attributes this to pectin slowing stomach emptying, physically slowing sugar absorption, and delaying the release of gut hormones tied to digestion.

Conclusion: The authors conclude pectin has real, regulator-recognized benefits for cholesterol and post-meal blood sugar, along with promising but less-established effects on gut symptoms and immune function — while noting a major gap in the field: most studies don't report which specific type of pectin (citrus vs. apple vs. other) or what molecular structure they tested, making it hard to say precisely how much of any given pectin type is needed for a given effect.

Source: Weber AM, Pascale N, Gu F, Ryan EP, Respondek F. "Nutrition and Health Effects of Pectin: A Systematic Scoping Review of Human Intervention Studies." Nutrition Research Reviews, 2025, 38(1), 306-323. DOI: 10.1017/S0954422424000180.
https://www.cambridge.org/core/journals/nutrition-research-reviews/article/nutrition-and-health-effects-of-pectin-a-systematic-scoping-review-of-human-intervention-studies/01BF0759F09A2BBC419F333B8B1D4FF9

Apple-Derived Pectin Modulates Gut Microbiota, Improves Gut Barrier Function, and Attenuates Metabolic Endotoxemia in Rats with Diet-Induced Obesity

Overview

This is an animal study (not human) looking at whether apple-derived pectin could protect against the gut and metabolic damage caused by a high-fat, obesity-inducing diet in rats.

Methods: Researchers fed rats a high-fat diet for 8 weeks to induce obesity, then split the heaviest rats into two groups for 6 more weeks: one continued the high-fat diet alone, the other got the same high-fat diet with pectin added (5% of total diet by weight). A third group ate normal rat chow throughout as a healthy baseline for comparison.

Results: Rats on the pectin-supplemented high-fat diet gained meaningfully less weight and body fat than rats on the high-fat diet alone, and had lower total cholesterol. At the gut level, the high-fat diet alone caused a well-documented unhealthy shift in gut bacteria balance (more Firmicutes, less Bacteroidetes — a pattern often associated with obesity), reduced a protective gut enzyme called intestinal alkaline phosphatase, and weakened tight-junction proteins (claudin-1, occludin, ZO-1) that hold gut lining cells together. Pectin supplementation reversed or partially reversed all of these changes, restoring gut bacteria balance close to the healthy-diet group and significantly increasing claudin-1 levels. The pectin group also showed lower blood levels of endotoxin (a bacterial toxin that leaks into the bloodstream when the gut lining is compromised) and lower inflammatory markers (TNFα, IL-6) both in the gut tissue and in the bloodstream.

Conclusion: The researchers concluded that apple-derived pectin helped protect gut barrier integrity and reduce the downstream inflammation and metabolic damage caused by a high-fat diet in this rat model, and suggested it may be a useful strategy worth testing in humans for metabolic disorders.

Source: Jiang T, Gao X, Wu C, et al. "Apple-Derived Pectin Modulates Gut Microbiota, Improves Gut Barrier Function, and Attenuates Metabolic Endotoxemia in Rats with Diet-Induced Obesity." Nutrients, 2016, 8(3), 126. PMID: 26938554; PMCID: PMC4808856.
https://pmc.ncbi.nlm.nih.gov/articles/PMC4808856/

GUM ARABIC

The Effect of Gum Arabic (Acacia senegal) on Cardiovascular Risk Factors and Gastrointestinal Symptoms in Adults at Risk of Metabolic Syndrome: A Randomized Clinical Trial

Overview

This is a real human RCT — 80 adults at risk of metabolic syndrome (average BMI ~34, so a heavier population than a general wellness audience), randomized to either 20g of gum arabic daily or a 1g pectin placebo, for 12 weeks. 61 participants completed it. This is the same study I cited earlier for the bloating/bowel movement claim, so worth going through it in full detail now that we have it.

What actually improved (statistically significant):

• Blood pressure — both systolic and diastolic dropped meaningfully in the gum arabic group, with no change in placebo
• Fasting blood glucose — decreased in the gum arabic group
• Self-reported bloating — 52% of the gum arabic group reported reduced bloating vs. 20% of placebo
• Self-reported bowel movements — 55% reported improvement vs. 33% of placebo
• Satiety — measured 60 minutes after taking it, the gum arabic group reported significantly higher fullness than placebo
• Dietary fiber and carbohydrate/calorie intake — the gum arabic group's reported fiber intake rose sharply and their carb/calorie intake fell, though this is self-reported diet data, not a direct physiological measurement

What did NOT improve (important to flag):

• Body weight, BMI, waist circumference, and body fat percentage — no significant change in either group
• Total cholesterol, LDL, HDL, and triglycerides — no significant change in either group
• Abdominal pain, "better digestion," and nausea — trended better in the gum arabic group but did not reach statistical significance

Conclusion: The authors conclude 20g/day of gum arabic for 12 weeks improved blood pressure, fasting glucose, satiety, and self-reported bowel comfort in people at risk of metabolic syndrome — but explicitly did not find a weight, BMI, or cholesterol benefit in this trial, which contradicts some earlier, smaller gum arabic studies that did find weight/BMI effects at similar doses.

Source: Jarrar AH, Stojanovska L, Apostolopoulos V, et al. "The Effect of Gum Arabic (Acacia senegal) on Cardiovascular Risk Factors and Gastrointestinal Symptoms in Adults at Risk of Metabolic Syndrome: A Randomized Clinical Trial." Nutrients, 2021, 13(1), 194. PMID: 33435475; PMCID: PMC7826716.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7826716/

Prebiotic Potential of Gum Arabic for Gut Health

Overview

This editorial reviews existing literature on gum arabic (Gum Acacia), a natural polysaccharide derived from Acacia tree exudates, and its properties as a prebiotic fiber in the human gut.

Findings: Gum arabic resists digestion in the small intestine and is fermented by bacteria in the large intestine into short-chain fatty acids, particularly propionic acid. This fermentation has a bifidogenic effect, increasing populations of Bifidobacterium and Lactobacillus while inhibiting bacteria such as Clostridium. The combination of SCFAs produced improves gut barrier function, reduces inflammation, and improves immune response. Gum arabic also increases stool water content and stool output. Intestinal tolerance is described as excellent, with high daily doses consumed without adverse reactions. A dose of 10g/day is cited as showing prebiotic potential. Separately, fermentation of gum arabic was linked to reduced luminal ammonia concentrations in the large intestine, via a mechanism involving the bacterium Prevotella ruminicola using ammonia as a nitrogen source, which the authors suggest could be relevant for patients with renal or hepatic disease.

Conclusion: The authors conclude gum arabic holds promise as a natural prebiotic with potential health benefits, while calling for further research to fully understand its mechanisms, standardized methods for measuring prebiotic activity, and increased education on its role in gut health.

Source: Elnour AAM, Abdurahman NH, Musa KH, Rasheed Z. "Prebiotic Potential of Gum Arabic for Gut Health." Medicine (Baltimore), 2023, 102(44), e35818. PMID: 37929233; PMCID: PMC10624802.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10624802/

AKKERMANSIA MUCINIPHILA

Supplementation with Akkermansia muciniphila in Overweight and Obese Human Volunteers: A Proof-of-Concept Exploratory Study

Overview

A randomized, double-blind, placebo-controlled pilot study testing daily oral supplementation of Akkermansia muciniphila (10^10 bacteria, in either live or pasteurized form) for three months in overweight/obese, insulin-resistant adults. 40 volunteers were enrolled and 32 completed the trial. Primary endpoints were safety, tolerability, and metabolic parameters (insulin resistance, circulating lipids, visceral adiposity, body mass); secondary outcomes were gut barrier function (plasma lipopolysaccharides) and gut microbiota composition.

Findings: Daily supplementation, either live or pasteurized, was safe and well tolerated. Compared to placebo, pasteurized A. muciniphila improved insulin sensitivity (+28.62 ± 7.02%, P = 0.002), and reduced insulinemia (-34.08 ± 7.12%, P = 0.006) and plasma total cholesterol (-8.68 ± 2.38%, P = 0.02). Pasteurized A. muciniphila also slightly decreased body weight (-2.27 ± 0.92 kg, P = 0.091) compared to placebo, and fat mass (-1.37 ± 0.82 kg, P = 0.092) and hip circumference (-2.63 ± 1.14 cm, P = 0.091) compared to baseline — though these three body-composition results did not reach standard statistical significance (P < 0.05). After three months, A. muciniphila reduced blood markers of liver dysfunction and inflammation, while overall gut microbiome structure was unaffected.

Conclusion: The authors conclude this proof-of-concept study demonstrates the intervention was safe and well tolerated, and that A. muciniphila supplementation improves several metabolic parameters.

Source: Depommier C, Everard A, Druart C, et al. "Supplementation with Akkermansia muciniphila in Overweight and Obese Human Volunteers: A Proof-of-Concept Exploratory Study." Nature Medicine, 2019, 25(7), 1096-1103. PMID: 31263284; PMCID: PMC6699990. DOI: 10.1038/s41591-019-0495-2.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6699990/

The Role of the Probiotic Akkermansia muciniphila in Brain Functions: Insights Underpinning Therapeutic Potential

Overview

A narrative review summarizing evidence on Akkermansia muciniphila's role in the gut-brain axis and its association with neuropsychiatric disorders, including mechanisms of action, correlations with specific diseases, and factors affecting its abundance.

Findings: A. muciniphila was first identified in 2004 and resides mostly in the mucus layer of the gastrointestinal tract, representing 3-5% of the microbial community and 1-4% of the fecal microbiome. Proposed mechanisms in the gut-brain axis include protection of the intestinal mucosal barrier (increasing mucus-producing goblet cells, upregulating tight-junction proteins ZO-1 and occludin, increasing transepithelial electrical resistance), modulation of the immune system (reducing pro-inflammatory cytokines TNF-α, IL1α, IL6, IL12A; increasing anti-inflammatory IL-10), and production of metabolites including short-chain fatty acids (propionate, butyrate, acetate) and amino acid derivatives that affect neurotransmitter levels (GABA, glutamate, serotonin) and neurotrophic factors.

The review catalogs associations between A. muciniphila abundance and various neuropsychiatric conditions, noting these associations are inconsistent across conditions and studies: abundance is reported decreased in depression/anxiety, Alzheimer's disease/cognitive deficit, substance use disorders, and epilepsy in most cited studies, but increased in multiple sclerosis and Parkinson's disease. For autism spectrum disorders and stroke, cited studies report conflicting directions of change. The review notes contradictory findings even within some categories — for example, A. muciniphila exacerbated inflammation in one Salmonella-infection mouse model, and was suggested as both a pathogenic marker and a compensatory beneficial factor in different multiple sclerosis studies.

On aging: a systematic analysis of 27 human studies found Akkermansia positively correlated with individual lifespan and health. Multiple studies of centenarians (Italy, China, South Korea) found significantly higher Akkermansia levels compared to younger elderly or adult comparison groups. One cited study found abundance was three-fold greater in individuals showing healthy aging versus non-healthy aging. In mouse models, oral Akkermansia administration for one to nine months was associated with improved behavior, immune function, cognitive function, muscle atrophy measures, and lifespan.

The review states that most of the evidence for neuropsychiatric applications is preclinical (animal models) or correlational (human observational studies), with direct clinical intervention trials for these conditions largely lacking.

Conclusion: The authors conclude that A. muciniphila is linked to multiple neuropsychiatric disorders via gut-brain axis mechanisms involving the mucosal barrier, immune system, and metabolites, and that it holds therapeutic potential — particularly for depression/anxiety and Alzheimer's/cognitive impairment — but state that comprehensive preclinical work and well-designed clinical studies are still needed to establish direct evidence of efficacy in these disorders.

Source: Xu R, Zhang Y, Chen S, Zeng Y, Fu X, Chen T, et al. "The Role of the Probiotic Akkermansia muciniphila in Brain Functions: Insights Underpinning Therapeutic Potential." Critical Reviews in Food Science and Nutrition, 2023, 63(1), 151-176. DOI: 10.1080/1040841X.2022.2044286.
https://www.tandfonline.com/doi/full/10.1080/1040841X.2022.2044286#infos-holder

Potential Effects of Akkermansia muciniphila in Aging and Aging-Related Diseases: Current Evidence and Perspectives

Overview

A narrative review examining the association between Akkermansia muciniphila and aging, and its role in specific aging-related diseases (vascular degeneration, neurodegenerative diseases, osteoporosis, chronic kidney disease, and type 2 diabetes), along with proposed mechanisms of action.

Findings: A. muciniphila abundance generally decreases with age in the human gut, but several studies found it significantly enriched in healthy, long-lived older adults and centenarians compared to less healthy older populations, and found reduced abundance as centenarians' health declined. In preclinical (animal) studies, A. muciniphila supplementation was associated with increased gut mucus layer thickness, improved immune status, extended lifespan in prematurely-aged mice, restored cognitive function and muscle atrophy measures, improved immune cell function (chemotaxis, phagocytosis, NK cell activity), reduced oxidative stress and pro-inflammatory cytokines, and improved glucose sensitivity and intestinal barrier function in aged mice.

For specific age-related diseases, the review summarizes (primarily animal/preclinical) evidence that A. muciniphila supplementation was associated with reduced atherosclerosis, suppressed abdominal aortic aneurysm formation, reduced vascular calcification, reduced amyloid plaque and improved cognition in Alzheimer's disease models, improved motor symptoms in ALS models (via increased nicotinamide levels), increased bone formation and reduced bone breakdown in osteoporosis models, improved kidney function in chronic kidney disease models, and improved insulin sensitivity/reduced insulinemia in type 2 diabetes models. The review cites the Depommier et al. 2019 human RCT (32 obese volunteers) as evidence that pasteurized A. muciniphila improved insulin sensitivity, reduced insulinemia, total cholesterol, body weight, and fat mass in humans, noting this avoids safety concerns associated with live bacteria.

The review reports an important exception: in Parkinson's disease, multiple studies found A. muciniphila abundance increased rather than decreased in patients, and cites one study suggesting over-colonization may accelerate disease progression by promoting aggregation of a disease-related protein (α-synuclein) in intestinal cells. The authors describe this as an open, unresolved question, noting most animal models of Parkinson's don't replicate this increase, and that the increased abundance in patients could alternatively be a compensatory beneficial response.

Proposed mechanisms include: increased production of short-chain fatty acids and nicotinamide in circulation; maintenance of the intestinal barrier (mucus layer, tight junction proteins); and secretion of functional proteins (e.g., protein "P9") and extracellular vesicles that act on organs beyond the gut.

Conclusion: The authors conclude that evidence generally points toward A. muciniphila playing a beneficial role in healthy aging and most aging-related diseases studied, with the clear exception of the unresolved and possibly harmful association in Parkinson's disease. They state most evidence originates from animal models rather than human clinical trials, that safety/regulatory approval for commercial use remains a barrier, and that supplementation amounts may need to be tailored to different populations given uncertainty about effects of excessive abundance.

Source: Zeng SY, Liu YF, Liu JH, Zeng ZL, Xie H, Liu JH. "Potential Effects of Akkermansia muciniphila in Aging and Aging-Related Diseases: Current Evidence and Perspectives." Aging and Disease, 2023. PMID: 37199577; PMCID: PMC10676789.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10676789/

The Gut Microbiota During a Behavioral Weight Loss Intervention

Overview

An ancillary study of the DRIFT2 trial, an ongoing randomized behavioral weight loss trial comparing daily caloric restriction (DCR) to intermittent fasting (IMF) in overweight/obese adults. This study examined fecal gut microbiota via 16S rRNA gene sequencing at baseline and three months into the intervention in 59 participants (25 DCR, 34 IMF), alongside clinical measures (weight, waist circumference).

Findings: Participants lost significant weight (mean 5.8 ± 3.8 kg) and waist circumference (mean 8.3 ± 5.7 cm) over the first three months, with over half losing at least 5% of baseline body weight. Overall gut microbiota composition shifted significantly during this period, with five genera changing significantly in relative abundance (Subdoligranulum and Collinsella decreased; Parabacteroides, Alistipes, and Bacteroides increased), and microbial diversity increased. Baseline gut microbiota composition (weighted UniFrac) was predictive of percent change in waist circumference but not weight change. Several specific bacterial genera at baseline and changes in specific genera during the intervention were associated with weight or waist circumference changes, though most did not show simple linear relationships. Change in dietary energy intake, not weight change itself, was the strongest predictor of change in gut microbiota composition.

Comparing the two intervention groups specifically: there were no significant differences between DCR and IMF in overall gut microbiota diversity changes. However, one genus — Akkermansia — showed a significant between-group difference: it increased significantly in the IMF group but showed no significant change in the DCR group. The authors note Akkermansia (primarily A. muciniphila) has been causally linked in animal models to lower body fat mass, improved glucose homeostasis, decreased adipose tissue inflammation, and increased gut integrity, and is a producer of the short-chain fatty acid acetate, which has been linked in animal models of intermittent fasting to "beiging" of white adipose tissue (a process associated with improved insulin sensitivity and energy expenditure).

Conclusion: The authors conclude that gut microbiota composition changes significantly during early dietary weight loss intervention, that baseline and changing microbiota features are associated with clinical outcomes (particularly waist circumference), and that intermittent fasting specifically was associated with an increase in Akkermansia abundance not seen with daily caloric restriction. They note the trial is ongoing and blinded, so between-group differences in clinical outcomes (weight, waist circumference) could not yet be reported or correlated with the microbiota findings at the time of publication.

Source: Stanislawski MA, Frank DN, Borengasser SJ, et al. "The Gut Microbiota During a Behavioral Weight Loss Intervention." Nutrients, 2021, 13(9), 3248. PMID: 34579125; PMCID: PMC8471894.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8471894/

Function and Therapeutic Prospects of Next-Generation Probiotic Akkermansia muciniphila in Infectious Diseases

Overview

A narrative review summarizing A. muciniphila's basic characteristics, genomic diversity, antibiotic resistance profile, and its documented effects (mostly from animal and in vitro studies) on various infectious diseases, along with proposed mechanisms for its interaction with the host gut barrier and immune system.

Basic characteristics: A. muciniphila makes up 3-5% of the human gut microbiome and colonizes the mucus layer, using mucin as its primary energy source. It has been isolated from feces, the upper digestive tract, breast milk, and (in one case) blood. Oral doses up to 10^10 CFU (live or dead) have been reported safe in human volunteers, and in 2021 the European Food Safety Authority approved pasteurized A. muciniphila for use as a novel food. Genomic analysis has identified multiple distinct phylogroups/subspecies with different metabolic properties, growth rates, and oxygen sensitivities. Some strains carry antibiotic resistance genes (to sulfonamides, aminoglycosides, and others); the review notes inconsistent susceptibility results across studies and calls for standardized testing protocols, but states current evidence suggests low risk of horizontal transfer of resistance genes due to the absence of mobile genetic elements in tested genomes.

Infectious disease associations (Table 1, primarily animal/cell studies): The review catalogs effects across several infection models: reduced mortality and organ damage in septic mice/piglets via an A. muciniphila-derived tripeptide (RKH) that binds Toll-like receptor 4; reduced weight loss/mortality in H7N9 influenza-infected mice; elevated A. muciniphila abundance in COVID-19 patients that positively correlated with inflammatory cytokines (IL-1β, IL-6, CXCL8); reduced inflammatory markers and improved survival in a tick-borne virus (SFTSV) infection model; improved outcomes and reduced inflammation in C. difficile-infected mice and in a Caco-2 cell model; reduced symptoms in Citrobacter rodentium-induced colitis in mice; decreased periodontal tissue destruction in two separate periodontitis models (P. gingivalis and F. nucleatum); reduced systemic Listeria monocytogenes infection in high-fat-diet mice.

For Salmonella (S. typhimurium) infection, the review reports directly conflicting results between two studies: one found A. muciniphila colonization worsened inflammation and infection severity in a gnotobiotic mouse model, while a separate study using a different mouse model found both live and pasteurized A. muciniphila reduced pathogen burden and inflammation. The authors state this discrepancy may reflect differences in microbial community composition and infection conditions between the two models, and that further research is needed.

Proposed host interaction mechanisms: The review describes A. muciniphila as regulating host immune response (via metabolites and outer membrane components affecting Toll-like receptor signaling and cytokine production), enhancing intestinal barrier function (increasing tight junction proteins ZO-1 and occludin, increasing mucin-producing goblet cells, increasing trans-epithelial electrical resistance), and producing short-chain fatty acids (butyrate, propionate, acetate) that affect host metabolism, including reversing diet-induced fasting hyperglycemia and improving glucose tolerance in mouse models.

Conclusion: The authors conclude A. muciniphila shows beneficial effects across a range of infectious disease models (oral, respiratory, gut, and systemic infections) primarily by reducing pathogen burden, infection symptoms, and inflammation. They state that most current evidence comes from in vitro or animal studies, that some studies report directly conflicting therapeutic effects (citing the Salmonella example), and that clinical trials are needed to confirm safety and efficacy in humans, along with further research on antibiotic resistance transfer risk and regulatory approval pathways before clinical application.

Source: Li L, Li M, Chen Y, et al. "Function and Therapeutic Prospects of Next-Generation Probiotic Akkermansia muciniphila in Infectious Diseases." Frontiers in Microbiology, 2024, 15, 1287858. PMID: 38384263; PMCID: PMC10880487.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10880487/

BACILLUS COAGULANS

Bacillus coagulans as a Potent Intervention for Treating Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Randomized Control Trials

Overview

A systematic review and meta-analysis of randomized controlled trials evaluating Bacillus coagulans (BC) versus placebo for irritable bowel syndrome (IBS) symptoms. Seven RCTs (477 total patients) were included after searching seven databases (PubMed, Cochrane, Web of Science, Google Scholar, SCOPUS, ClinicalTrials.gov, EBSCO). Studies used different BC strains (Unique IS2, MTCC 5856, GBI-30 6086, LBSC) across adult and pediatric IBS populations, with follow-up periods ranging from 4 to 90 days depending on the study.

Findings: BC significantly improved several IBS symptom severity measures compared to placebo: urgency (MD: -1.05), bowel habit satisfaction (MD: -1.40), straining (MD: -1.22), passage of gas (MD: -1.25), incomplete evacuation (MD: -1.06), and total symptom severity score (MD: -10.13, P < 0.00001). Physician's global assessment of disease severity was significantly improved at 8 weeks (P = 0.002) but not at 4 weeks (P = 0.48), suggesting a delayed onset of physician-rated improvement. Discomfort score decreased significantly at 4 and 8 weeks. Bloating score decreased significantly at 2, 4, 8, and 11 weeks. Vomiting score also decreased. Abdominal pain score was significantly reduced at 2, 4, 8, and 11-13 weeks, with the effect size generally increasing at later time points (SMD ranging from -0.84 at week 2 to -1.81 at 11-13 weeks). Four of the seven included studies were judged low risk of bias, two had some concerns, and one was judged high risk of bias.

The review notes that pooling data by strain found no significant difference in pain-score efficacy between different BC strains tested, though it also cites conflicting results from other published meta-analyses regarding specific strains (e.g., one other meta-analysis found MTCC5856 non-significant for abdominal pain, contrary to this review's findings).

Conclusion: The authors conclude BC is an effective probiotic for reducing IBS symptom severity and abdominal pain, with no serious adverse events reported, and that the timing data suggest BC symptom benefits (particularly physician-assessed improvement) may take longer than 4 weeks to become statistically significant. They call for future studies comparing different BC subspecies directly and evaluating long-term use.

Source: AbdelQadir YH, Nabhan AI, Althawadi YJ, et al. "Bacillus coagulans as a Potent Intervention for Treating Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Randomized Control Trials." Gastroenterology & Endoscopy, 2023. DOI: 10.1016/j.gande.2023.11.001.
https://www.sciencedirect.com/science/article/pii/S2949752323000614

Probiotic Characteristics of Bacillus coagulans and Associated Implications for Human Health and Diseases

Overview

A narrative review covering the gastrointestinal life cycle of B. coagulans in humans, its mechanisms of action on digestion, gut/vaginal microbiota, and the immune system, and a summary of clinical trials examining its use in various human diseases.

Basic characteristics: B. coagulans is a lactic acid-producing, spore-forming, facultative anaerobic bacterium, first isolated from spoiled canned milk by Hammer in 1915, and formerly mislabeled as Lactobacillus sporogenes before being reclassified into genus Bacillus. It has Generally Recognized As Safe (GRAS) status from the FDA; one safety study found a dose as high as 9.52 × 10^11 CFU was well tolerated in a 70kg adult. Genomic analysis found its antibiotic-resistance-related genes were not easily transferable to other bacteria.

Gastrointestinal life cycle: The review proposes a three-stage life cycle: spores survive transit through the stomach (~3 hours) protected by their spore structure; germinate and proliferate in the upper small intestine (residence time 2-5 hours) where nutrient conditions favor germination; then travel to the large intestine, where sporulation resumes in the lower colon due to nutrient-poor conditions. In vitro digestive models found the germination ratio of B. coagulans PTA-6086 (93%) considerably higher than B. subtilis C-3102 (8%), though the review notes other studies have found poor long-term colonization ability, suggesting B. coagulans affects gut microbiota mainly through temporary proliferation rather than permanent colonization.

Digestive/metabolic effects: B. coagulans strains produce various enzymes (β-galactosidase, α-galactosidase, α-amylase, lipase, alkaline proteases) that aid digestion of lactose, protein, and carbohydrates. Cited studies report strains improved bowel movement frequency and stool consistency, reduced intestinal ammonia and fecal odor compounds, enhanced gut lining cell health by decreasing inflammation, and (in animal studies) reduced blood cholesterol and secondary bile acid production.

Microbiota effects: B. coagulans is proposed to help create an anaerobic, acidic gut environment unfavorable to pathogens, and some strains produce antimicrobial compounds including a bacteriocin (coagulin) active against gram-positive bacteria. Cited studies found it increased populations of Lactobacillus and Bifidobacteria and competitively excluded pathogens like vancomycin-resistant enterococci and E. coli. Separately, studies cited found B. coagulans strains improved bacterial vaginosis symptoms as an adjunct to antibiotic treatment.

Immune effects: Cited studies (summarized in a table) report B. coagulans strains alleviated colitis and inflammation markers in mice, reduced pro-inflammatory cytokines (TNF-α, IL-2) in various models, induced apoptosis in colon cancer cell lines in vitro, and in human cell studies increased or modulated various immune cytokines (IL-10, IL-4, IL-6, IFN-γ, TNF-α) depending on the specific study and stimulation condition. One human study in antiretroviral-treated HIV-1 patients found no significant biomarker changes from the probiotic but noted correlations between some inflammatory markers.

Clinical trials on GI disorders (summarized in a table): Multiple cited trials report B. coagulans strains improved IBS symptoms (abdominal pain, bloating, bowel movements) over 8-90 days across adult, elderly, and one pediatric study; improved constipation symptoms and stool characteristics; reduced acute diarrhea duration in two studies. However, one cited Indian study found B. coagulans had no therapeutic effect on acute dehydrating diarrhea (including rotavirus-associated diarrhea) in infants, contradicting other studies; the review authors attribute conflicting results to possible strain-dependent effects, formulation, and dosage differences. A separate cited study found B. coagulans supplementation was not effective in reducing death or necrotizing enterocolitis in very low birth weight infants, though it improved feeding tolerance.

Metabolic and other disease applications: Cited studies report B. coagulans combined with other interventions improved outcomes in obese patients undergoing bariatric surgery, reduced cholesterol and triglycerides in animal models, showed benefit as an adjuvant in rheumatoid arthritis in one clinical trial and animal studies, showed anti-proliferative/apoptotic effects on cancer cell lines in vitro, and reduced markers of depression (alongside IBS symptoms) in one cited mouse study.

Conclusion: The authors conclude B. coagulans shows potential across a range of human diseases via direct and indirect (microbiota-mediated) mechanisms affecting digestion, immune function, and metabolism, but note that many of its effects are strain-dependent, and suggest combining different strains may maximize benefits in future applications.

Source: Cao J, Yu Z, Liu W, Zhao J, Zhang H, Zhai Q, Chen W. "Probiotic Characteristics of Bacillus coagulans and Associated Implications for Human Health and Diseases." Journal of Functional Foods, 2020, 64, 103643. DOI: 10.1016/j.jff.2019.103643.
https://www.sciencedirect.com/science/article/pii/S1756464619305675

 

References:

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC11600113/
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC7360457/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC8912540/
4. https://www.sciencedirect.com/science/article/abs/pii/S025462992600253X
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC6266414/
6. https://www.mdpi.com/1648-9144/62/2/329
7. https://www.cambridge.org/core/journals/nutrition-research-reviews/article/nutrition-and-health-effects-of-pectin-a-systematic-scoping-review-of-human-intervention-studies/01BF0759F09A2BBC419F333B8B1D4FF9
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC4808856/
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC7826716/
10. https://pmc.ncbi.nlm.nih.gov/articles/PMC10624802/
11. https://pmc.ncbi.nlm.nih.gov/articles/PMC6699990/
12. https://www.tandfonline.com/doi/full/10.1080/1040841X.2022.2044286#infos-holder
13. https://pmc.ncbi.nlm.nih.gov/articles/PMC10676789/
14. https://pmc.ncbi.nlm.nih.gov/articles/PMC8471894/
15. https://pmc.ncbi.nlm.nih.gov/articles/PMC10880487/
16. https://www.sciencedirect.com/science/article/pii/S2949752323000614
17. https://www.sciencedirect.com/science/article/pii/S1756464619305675