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gut

These Are the Best Foods & Supplements for Gut Health

Posted on January 20th 2025 (5 months)

In this clip, Dr. Rhonda Patrick discusses dietary strategies to improve gut health, including fermented foods, probiotics, and glutamine supplementation.

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Q&A #48 with Dr. Rhonda Patrick (6/3/23)

Posted on June 13th 2023 (about 2 years)

Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.

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Q&A #39 with Dr. Rhonda Patrick (9/03/2022)

Posted on September 3rd 2022 (almost 3 years)

Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.

Topic Pages

  • Blood-brain barrier

    Microbial metabolites from the gut modulate blood–brain barrier tight-junction expression via systemic cytokine and vagus-mediated signaling.

  • Butyrate

    Gut microbiota ferment indigestible fibers into butyrate, which fuels colonocytes, strengthens tight junctions, and attenuates mucosal inflammation.

  • Intestinal permeability

    Intestinal permeability is a functional property of the gut epithelium governed by tight-junction dynamics and mucosal signaling.

  • Lactobacillus reuteri

    In the gut, Lactobacillus reuteri adheres to intestinal epithelium, produces reuterin, and modulates immune signaling to stabilize microbiota.

  • Polyphenols

    Polyphenols modulate gut microbiota composition and activity, while microbes biotransform polyphenols into bioactive metabolites affecting host physiology.

  • Toll-like receptors

    Gut epithelial and lamina propria immune cells express Toll-like receptors that sense microbial patterns and initiate NF-κB–mediated innate immunity.

  • Vitamin D

    Vitamin D, through gut epithelial VDR activation, strengthens mucosal tight junctions, induces antimicrobial peptides, and shapes microbiome composition.

News & Publications

  • Common dietary emulsifiers found in processed foods can disrupt glucose regulation and alter the gut microbiota, potentially driving metabolic and immune dysfunction. www.nature.com
    Gut Microbiome Metabolism

    The additives that make processed foods creamy, smooth, and long-lasting might come with a hidden cost. A recent study in mice found that common dietary emulsifiers disrupt glucose regulation and alter the gut microbiota, potentially contributing to metabolic disorders and immune dysfunction.

    Researchers fed mice diets containing four commonly used emulsifiers: lecithin, sucrose esters, carboxymethylcellulose, and mono- and diglycerides. Then, they analyzed how the compounds affected the gut’s protective mucus barrier and microbial diversity.

    They found that sucrose esters and carboxymethylcellulose elevated the animals' blood glucose and lipids, disrupted glucose regulation, and altered gut microbiota. Similarly, mono- and diglycerides impaired glucose and lipid metabolism, but they also raised markers of inflammation and increased bacterial encroachment into the gut mucus layer, potentially impairing immune function.

    These findings suggest that dietary emulsifiers promote metabolic dysfunction by altering the gut microbiota and disrupting glucose and lipid regulation. Notably, the amounts of emulsifiers in the animals' diets represented a much higher proportion of dietary intake than what humans typically consume, as emulsifiers in processed foods are usually in smaller amounts. Still, long-term consumption could increase exposure through a diet high in processed foods containing emulsifiers.

    Emulsifiers are common in processed foods, including ice cream, baked goods, margarine, salad dressings, and sauces. They help stabilize mixtures of oil and liquids, improving texture and shelf life. Their use reflects the broader role of food additives, which enhance flavor, preserve freshness, and improve processed food products' visual and textural appeal—often at the expense of health. Learn more about the harms of processed foods in Aliquot #111: Why ultra-processed foods and their additives are harmful.

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  • The absence of gut microbes limits exercise capacity and reduces glucose utilization, highlighting the surprising role of microbiota in physical endurance. www.nature.com
    Exercise Gut Microbiome Performance Microbes

    If you’re struggling with exercise performance, your gut health might be partly to blame. The gut microbiota is critical for boosting exercise performance and regulating energy metabolism. A recent study found that mice without gut microbes, known as germ-free mice, had lower exercise capacity and used oxygen and glucose less efficiently during physical activity.

    Researchers compared germ-free mice to mice with normal gut bacteria. They fed both groups a regular diet and allowed them to exercise on running wheels. They measured the animals' body composition, oxygen and carbon dioxide usage, and glucose levels to assess how the absence of gut microbes affected exercise performance and energy use.

    They found that germ-free mice gained less weight, had lower fat mass, and had lower aerobic exercise capacity than mice with normal gut bacteria. Germ-free mice also exhibited reduced glucose storage and usage, impairing their capacity to fuel physical activity. Additionally, their fat tissue adapted by breaking down more fat, making them leaner and less prone to obesity, but at the cost of reduced energy availability during physical activity.

    These findings suggest that the absence of gut bacteria limits the body’s ability to store and use glucose, adversely affecting exercise performance. They also highlight gut microbes' vital role in supporting metabolism and physical endurance. Learn more about gut microbes' effects on metabolism in this clip featuring Dr. Michael Snyder.

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  • Infant gut microbes including Actinobacteria and Bifidobacterium linked to improved social attention tests, suggesting a role for the microbiome in early cognitive development. neurosciencenews.com
    Brain Gut Microbiome Development

    The gut-brain axis is a complex communication system that links the gut microbial community, digestive system, and nervous system. A new study shows that the gut-brain axis plays a critical role in brain development. Infants demonstrating specific patterns of enhanced brain activity, such as rhythmic processing, exhibited unique gut microbial populations and metabolic processes.

    Researchers collected fecal samples from 56 infants between the ages of four and six months and analyzed their microbial composition through metagenomic sequencing. They evaluated the infants' brain activities while listening to a rhythmic beat via electroencephalogram (EEG). Then, using behavioral tests, they assessed aspects of the infants' cognitive abilities, including neural rhythm tracking, language discrimination, and joint attention.

    They found that infants who performed well in the joint attention test exhibited specific gut microbial patterns that included higher numbers of Actinobacteria, Bifidobacterium, and Eggerthella, and lower numbers of Firmicutes, Hungatella, and Streptococcus. The EEGs revealed unique neural activity patterns associated with enhanced rhythmic processing, which varied according to the presence of specific microbes. In addition, these neural activity patterns were associated with upregulated metabolic processes involving microbes linked with neurodevelopment.

    Neural rhythm tracking facilitates information organization across time, influencing perception, social communication, language, and cognition. Language discrimination differentiates between language and non-language. Joint attention is a social skill that influences infants' capacity to learn from others, affecting early language acquisition and overall cognition.

    This study was small; however, its findings suggest a potential connection between the gut microbiome and early cognitive development. It also highlights the intricacies of the gut-brain axis, with potential implications for understanding early brain development and cognitive function. Learn more about the role of the gut microbiota in this episode featuring Drs. Erica and Justin Sonnenburg.

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  • Kombucha reduces blood glucose levels by nearly 30 percent. www.frontiersin.org
    Nutrition Gut Diet Microbiome Diabetes

    Kombucha is a fermented beverage made from tea, sugar, bacteria, and yeast. Some evidence suggests that kombucha exerts antimicrobial, antioxidant, detoxifying, and liver-protective effects. A new study has found that kombucha lowers blood glucose levels by nearly 30 percent in people with type 2 diabetes.

    Researchers conducted a small trial involving 12 adults with type 2 diabetes. The participants drank approximately 8 ounces of either kombucha or a placebo beverage daily for four weeks. Eight weeks later, they switched to the other option. During each intervention, they measured their fasting blood glucose levels at the start and after one and four weeks. They completed questionnaires about their overall health, insulin needs, gut health, skin condition, and mental state. The researchers analyzed the kombucha’s microbiota and quantified its fermentation products.

    When the participants drank the kombucha, they experienced a notable drop in average fasting blood glucose levels by the end of the intervention compared to the start (164 versus 116 mg/dL – nearly 30 percent lower). However, the placebo group did not experience the same reduction (162 versus 141 mg/dL – less than 13 percent lower). The microbiota analysis revealed lactic acid bacteria, acetic acid bacteria, and yeast as the dominant components. The primary fermentation products were lactic acid, acetic acid, and ethanol.

    This was a very small study, but the findings suggest that kombucha might have blood glucose-lowering potential for people with diabetes. Learn how consuming fermented foods, such as kombucha, kefir, and others, increases gut microbial diversity and decreases inflammation in this clip from a live Q&A with Dr. Rhonda Patrick.

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  • Our gut microbiomes aren’t getting enough fibre, but supplements can help apple.news
    Gut Microbiome Fiber Supplements

    Prebiotic supplements can compensate for low fiber intake.

    Dietary fiber refers to the indigestible components of plant-based foods. A growing body of evidence indicates that eating a fiber-rich diet decreases the risks of many chronic diseases, such as coronary heart disease, stroke, hypertension, diabetes, and some types of cancer, including breast cancer and colon cancer. Most people living in the United States only get about half of the recommended amounts of fiber daily. Findings from a recent study suggest that prebiotic supplements can compensate for dietary shortcomings in fiber intake by promoting short-chain fatty acid production.

    Prebiotics are food components that support the maintenance of a healthy microbiota and create an environment that is conducive to its survival. Fructo-oligosaccharides, galacto-oligosaccharides, and trans-galacto-oligosaccharides are the most common prebiotics. Their fermentation by gut microbiota produces short-chain fatty acids, including acetate, propionate, and butyrate. Many commonly consumed fruits and vegetables, such as apples, bananas, and legumes, contain prebiotics, but they are also available in dietary supplement form.

    The study involved 28 healthy adults between the ages of 18 and 70 years. Each participant took one of three prebiotic supplements (inulin, wheat dextrin, or galactooligosaccharides) twice daily for one week, followed by one week off. They repeated this process with all three of the supplement products. Participants provided stool samples, completed diet surveys, and answered online surveys about their experiences with the supplements. The investigators measured short-chain fatty acid concentrations and microbial makeup in the stool samples.

    They found that changes in short-chain fatty acid concentrations were person-specific and not related to which prebiotic supplement they took. Consequently, each participant’s response to the prebiotics was inversely related to their basal short-chain fatty acid concentration, which, in turn, was associated with their habitual fiber intake. Participants whose diets were low in dietary fiber experienced marked increases in butyrate production in their guts, likely due to increases in butyrate-producing microbes. However, participants whose diets were in high in dietary fiber experienced little change in the makeup of their gut microbes.

    These findings suggest that people whose diets are low in dietary fiber would benefit from supplemental prebiotics to promote short-chain fatty acid production and promote gut and overall health. Learn more about prebiotics in this episode featuring Dr. Eran Elinav.

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  • Compounds in e-cigarettes trigger inflammation, promoting a leaky gut. ucsdnews.ucsd.edu
    Gut Intestinal Permeability Lipopolysaccharide

    In recent years, vaping, or smoking electronic cigarettes (e-cigarettes), has emerged as a popular substitute for smoking tobacco-containing cigarettes. E-cigarettes produce a vapor that may contain nicotine as well as a variety of toxic substances, including some carcinogens. Findings from a new study suggest that some compounds in e-cigarettes trigger inflammation, promoting a leaky gut.

    Leaky gut, otherwise known as intestinal permeability, is a condition in which gaps form between the tight junctions between the endothelial cells that line the gut. These gaps allow pathogens like bacteria or endotoxins (toxins that are released when bacteria die) to leak through the intestinal wall and pass directly into the bloodstream. Leaky gut has been linked with a number of chronic diseases, including Alzheimer’s disease and cardiovascular disease.

    The authors of the study exposed mice to e-cigarette vapors for one hour per day and then they examined the animals' colons at one week and three months after the chronic exposure. Then they measured gene expression in the colons. They also built gut enteroids – three-dimensional tissue models that incorporate many of the features of human gut tissue, including an epithelial layer surrounding a functional lumen and all of the cell types normally found in the gut. They exposed the enteroids to e-cigarette vapor (with or without nicotine).

    They found that exposure to e-cigarette vapor promoted leaky gut, increasing the susceptibility of the gut lining to bacterial infections, and triggering gut inflammation. Use of the two models established that the primary components in the vapor responsible for the harmful effects were propylene glycol and vegetable glycerol, compounds present in more than 99 percent of all e-cigarettes. They also found that e-cigarette vapor altered expression of genes involved in the cellular response to stress, infection, and inflammation.

    These findings demonstrate that commonly used substances present in e-cigarettes promote leaky gut and drive inflammation and provide insights into the long-term health effects of e-cigarettes. They also underscore public health efforts to reduce e-cigarette use.

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  • Gut microbial conversion of glucosinolates to isothiocyanates is highly variable in humans. cancerpreventionresearch.aacrjournals.org
    Gut Microbiome Sulforaphane Isothiocyanates Myrosinase Glucoraphanin

    Glucoraphanin, a precursor to sulforaphane, is a type of glucosinolate found primarily in broccoli and kale. Its conversion to sulforaphane requires myrosinase, an enzyme co-located within the leaves, stems, and other components of the plants in which it is found. Cooking temperatures inactivate myrosinase, effectively preventing isothiocyanate conversion and allowing unhydrolyzed glucosinolates to pass into the gut. In humans, myrosinase-producing gut bacteria can convert these glucosinolates to their cognate isothiocyanates. Findings from a 2012 study indicate that microbial conversion of glucosinolates to isothiocyanates is highly variable.

    Previous research has demonstrated that sulforaphane administration promotes uniformly high urinary excretion of dithiocarbamate metabolites, accounting for as much as 90 percent of the administered sulforaphane over a 24-hour period. Dithiocarbamate levels in urine serve as a biomarker of glucosinolate intake.

    The study involved two dissimilar groups of people: rural Han Chinese and racially mixed Baltimoreans. The participants abstained from cruciferous vegetable consumption for three days prior to the beginning of the study. They had not taken antibiotics for two weeks prior. Each of the participants kept a food diary, provided their medical history, and kept track of their bowel activity. The participants took a glucoraphanin-rich broccoli sprout extract that provided 200 micromoles of glucoraphanin in water. The authors of the study collected urine samples from 8 a.m. to 4 p.m. and from 4 p.m. until 8 a.m. on the following morning.

    They found that microbial-induced conversion of glucoraphanin to sulforaphane is highly variable (ranging from 1 to 40 percent of dose) and subject to interindividual differences in gut bacteria populations. As such, conversion is distinguished by “high converters” – people with high elimination profiles, and “low converters”– those with low elimination profiles. The authors of the study identified no demographic factors that affected conversion efficiency, but they did note that conversion of glucoraphanin to dithiocarbamate was greater during the day.

    Watch this clip in which Dr. Jed Fahey describes some of the factors that influence the conversion of myrosinase-driven conversion of glucoraphanin to sulforaphane.

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  • A gut-brain axis specific to glucose drives sugar preference, potentially explaining sugar cravings. www.sciencedaily.com
    Gut Sugar

    Sugar provides necessary energy in the human diet, but excess sugar consumption is associated with weight gain and metabolic disorders. The average person living in the United States consumes approximately 100 pounds of sugar per year. Findings from a recent study suggest that our preference for sugar has its origins in the brain.

    The authors of the study gave mice water that was sweetened with either sugar or acesulfame, an artificial sweetener commonly used in diet drinks and foods. At first, the mice chose to drink both solutions, but after two days, the mice chose the sugar-sweetened water only.

    The researchers analyzed the brain activity of the mice when they drank the two solutions and found that a particular region of the brain responds to sugar – an area called the caudal nucleus of the solitary tract, which is located in the brain stem. They discovered that signals originating in the gut travel along the vagus nerve to this region of the brain to create a gut-brain-axis specific to glucose and similar molecules. Intake of these molecules stimulates even greater consumption, setting up an environment conducive to overconsumption.

    Identification of this neural pathway provides insights into human consumption of sugar and might inform the development of new strategies to reduce intake.

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  • Intermittent fasting increased gut bacteria diversity, reduced inflammation, demyelination, and axonal damage in multiple sclerosis (MS) animal model. www.cell.com
    Gut Microbiome Fasting Multiple Sclerosis Autoimmunity

    Intermittent fasting (every other day) increased gut bacteria diversity and reduced inflammation, demyelination, and axonal damage in multiple sclerosis (MS) animal model. A small pilot trial in humans with MS showed many similar changes to the gut microbiome and blood adipokines such as leptin. The effects of fasting on immune cells included a reduction of pro-inflammatory IL-17-producing T cells and increased numbers of T regulatory cells which prevent autoimmunity.

    The small pilot trial in humans showed increased bacteria richness in species that have previously been shown to promote T regulatory cell accumulation in the colon.

    Interestingly, this study did what is called a metagenomic analysis and found that the ketone pathway was enhanced in the gut microbiome by intermittent fasting. This is super interesting because bacteria in the gut normally produce short chain fatty acids and ketones from fermentable fiber but suggests that the gut microbiome regulates its own ketone body metabolism during fasting!

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