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science nutrition blog

science nutrition <strong>blog</strong>

By Michael J. Rudolph, Ph.D.


The time-honored motto, “You are what you eat,” suggests being healthy requires a well-balanced diet. While this is certainly true, the contemporary version of this proverbial saying should state, “You and your microbiome are what you eat.” This is because the microbiome, which contains a plethora of different types of bacteria that live in the gut, is a key contributor to overall health and microbiome impact on human health is heavily influenced by the food you eat. The microbiome in your gut is comprised of trillions of bacterial cells living symbiotically within the human gastrointestinal tract. In exchange for providing these bacteria somewhere to live along with an ample food supply, the microbiome in your gut breaks down some of the nutrients we consume into essential compounds that play a critical role in human physiology and health.

Diversify Your Microbiome

How to Improve Your Microbiome? Diet is the most effective way to improve diversity and function of the microbiome. For starters, increasing dietary intake of insoluble carbohydrates (fiber) also referred to as prebiotics, preferentially from raw fruits and vegetables, supports growth of a healthy microbiome. Eating more insoluble fiber can increase the number of bacteria that improve health, such as Bacteroidetes, in just a few weeks.1 Directly ingesting beneficial bacteria, or probiotics, also tends to improve microbiome function. The most commonly used probiotic organisms include Lactobacillus and Bifidobacterium. Evidence of a therapeutic effect of probiotics dates as far back as the early 20th century. A study describing improvement in autoimmune arthritis after supplementation with live cultures of Streptococcus lacticus and Bacillus bulgaricus was reported in 1909.2 More recent studies have shown probiotics protect against several gastrointestinal maladies such as irritable bowel disease, diarrhea and ulcerative colitis. To the contrary, eating a high-fat, nutrient-deficient diet negatively impacts the composition of your gut microbiome3, reducing its diversity, ultimately rendering it unable to convert certain foods into nutrients that bolster health and wellness.

Other lifestyle choices seemingly detrimental to a fitter microbiome include ingestion of processed foods, excessive use of antibiotics and too much stress. In fact, too much stress can reshape the gut bacteria’s composition through stress hormones and inflammation – favoring an unhealthier microbiome, which tends to release metabolites and neurohormones into the body that create a predilection for an unhealthy diet while boosting stress levels to even greater heights, creating a vicious cycle.4 Consequently, effective stress-reducing techniques like meditation should also help break this cycle by improving an ailing microbiome. Thankfully, there is increasing evidence indicating regular cardiovascular exercise benefits gut microbiota as well, which may be partially responsible for the comprehensive benefits of regular physical activity on health.5 Further scientific inquiry is needed to reveal the precise impact aerobic exercise frequency and intensity can have on the microbiome and whether resistance training has any impact on microbiome function at all.

Prebiotics Support a Healthier Microbiome

In addition to probiotics being an effective way to augment the microbiome, consuming prebiotics also improves microbiome diversity and function. Dietary prebiotics are nondigestible fiber that pass through the digestive tract, stimulating the growth and activity of advantageous bacteria in the colon by functioning as a fermentable energy source for these bacteria.6 Fermentation of prebiotic fiber by microbiomic bacteria in the gut generates copious amounts of short-chain fatty acids (SCFAs), which can mitigate obesity.7 Acetate, propionate and butyrate are the main SCFAs produced from microbial fermentation in the gut.8 Each of these SCFAs serve not only as energy substrates for the epithelial cells that line the gut but also as signaling molecules between the gut and other organs in the body.9

All three SCFAs decrease appetite and satiety employing different mechanisms. Acetate suppresses appetite and food intake by crossing the blood-brain barrier into the hypothalamic region of the brain where it stimulates lactate production, which mitigates hunger and feeding.10 Propionate directly stimulates production of the appetite-suppressing hormone leptin in human adipose tissue.11 Butyrate also prevents diet-induced obesity by suppressing activity of neurons that express the hunger-inducing neuropeptide Y in the hypothalamus, reducing food intake.12

Acetate, propionate and butyrate also inhibit a class of enzymes known as histone deacetylases (HDACs). Inhibition of HDACs in muscle tissue directly activates the PGC1-alpha gene, which then triggers mitochondrial biogenesis and function within muscle.13 Since mitochondria are the power-producing organelles within the cell that oxidize fat, the ability of SCFAs to enhance mitochondrial activity conceivably increases the ability to burn fat, explaining how an optimal microbiome can reduce obesity.

Optimize Your Microbiome With Capsaicin

Outside of prebiotics and probiotics, the phytochemical capsaicin is seemingly next in line as a very potent way to modulate microbiome function towards a leaner and healthier body. Capsaicin, and the related nonpungent capsinoids like capsiate, belong to a class of compounds that provide powerful antioxidant and anti-inflammatory effects while also improving cardiovascular health.14 Recent data shows regular consumption of chili-rich foods, loaded with capsaicin, reduces the likelihood of death from chronic diseases such as cancer and heart disease relative to those who did not consume chili-rich, spicy foods, suggesting capsaicin has considerable disease-fighting properties.15

The positive health impact from capsaicin, and capsinoids, is unquestionably intertwined with capsaicin’s rather uncommon fat-burning qualities. This compound class brings about fat loss in a very unique way promoting a process known as thermogenesis, which burns fat without converting the energy into ATP. Instead, the energy is directly converted into heat which effectively increases energy expenditure, ultimately leading to significant fat loss. Capsaicin can also reduce appetite16, further supporting the ability of this compound to torch body fat and, perhaps more importantly, keep it off. Although the appetite-suppressant effect of capsaicin has been observed in several trials, it is not entirely understood how capsaicin reduces appetite. There is some evidence that the release of noradrenaline triggered by capsaicin contributes to appetite reduction, as the stimulation of the noradrenaline receptors in the brain has been shown to produce feelings of satiety.17

There is mounting evidence suggesting capsaicin influences the composition and function of the microbiome, indicating some of capsaicin’s fat-burning and appetite-suppressing qualities come from a capacity to regulate the microbiome. Diversity of the microbiome is greater in healthy people relative to those who are obese.18 In a recent study by Wang et al.19, the researchers found capsaicin improves the diversity of gut microbiota while also decreasing body fat levels even in mice fed a high-fat diet. In the same study, Wang et al.19 also showed that capsaicin significantly increased the concentration of the fat-burning compounds acetate and propionate in the gut. Further analysis showed the reason more acetate and propionate were found was due to higher levels of a specific bacterial species in the gut of the capsaicin-treated mice, indicating capsaicin triggered growth of this healthy bacterium.

Capsaicin also has strong antibacterial activity and may reverse an unhealthy gut microbiota by killing harmful bacteria while stimulating beneficial bacteria as seen in the Wang et al. study. Taken together, these findings suggest in addition to the thermogenic fat-burning action of capsaicin, this spicy molecule also reduces body fat by improving microbiome diversity, increasing the relative amount of certain fat-lowering bacteria while coaxing these fat-lowering bacteria to produce more SFCAs, which systematically decreases appetite and stimulates fat loss.

Incidentally, if you're looking for a good capsaicin supplement after seeing the remarkable impact this molecule has on the microbiome, look no further than Advanced Molecular Labs remarkable product Thermo Heat®, which is chock full of capsaicin along with several additional ingredients that will transform your microbiome into a fat-burning furnace that will torch body fat and keep it off.


†These statements have not been evaluated by the U.S. Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

© Published by Advanced Research Media, Inc., 2022

© Reprinted with permission from Advanced Research Media, Inc.


For most of Michael Rudolph’s career he has been engrossed in the exercise world as either an athlete (he played college football at Hofstra University), personal trainer or as a research scientist (he earned a B.Sc. in Exercise Science at Hofstra University and a Ph.D. in Biochemistry and Molecular Biology from Stony Brook University). After earning his Ph.D., Michael investigated the molecular biological effects of exercise as a fellow at Harvard Medical School and Columbia University. That research contributed seminally to understanding the function of the incredibly important cellular energy sensor AMPK – leading to numerous publications in peer-reviewed journals including the journal Nature. Michael is currently a Senior Scientist working at the New York Structural Biology Center where he investigates the molecular nature of human illness and disease.




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