The human microbiome is a diverse and abundant system of fungi, yeast, viruses, and bacteria that impacts multiple bodily functions, including digestion, vitamin synthesis, neurotransmitter support, and healthy immune function. So it’s important to keep this intricate system in balance to maintain optimal function of these vital processes.

A balanced gut microbiome is accomplished by a healthy and varied diet, good sleep and exercise habits, and nutritional supplementation. Probiotics and prebiotics are the primary types of nutritional supplements that support a healthy microbiome. Probiotics provide the active, beneficial microorganisms that supplement the microbial component of your microbiome, while prebiotics are the “foods” that these microorganisms consume.

What is a prebiotic?

Prebiotics are found in various forms in the diet, most often as different types of fibers. Because fiber is difficult for the body to digest, it can end up undigested in the lower part of the GI tract where beneficial microbes in the gut break it down and utilize it for food.

Although fiber very effectively nourishes the microbiome, it can take days, or even weeks, to make a difference. Also, common side effects of supplementing with fiber can include bloating, gas, and changes in bowel patterns. Although many individuals tolerate these fibers very well, others might experience so much discomfort in their use that other prebiotic options are preferable.

Other natural compounds can serve as effective prebiotics for your microbiome, without supplementing with fiber. Bacteriophages are specialized organisms that can help rebalance the gut microbiome.* Certain non-fiber plant compounds, like flavones and polyphenols, can also contribute to a healthy, balanced microbiome.*

What are polyphenols?

Polyphenols are natural compounds in fruits, vegetables, grains, herbs, and spices that give foods their color and taste and protect them from damage. They offer a multitude of health benefits, including support for the microbiome.* Polyphenol benefits don’t stop at microbiome balance. They also act as potent antioxidants – combating physical stressors to cells, which we call “aging.”*

In addition, polyphenols support healthy brain function, help balance blood sugar levels, and support good digestion.* Because many polyphenols are only minimally absorbed, they make their way to the intestines where they are utilized by intestinal bacteria.

What do polyphenols have to do with microbiome health?

Support of short-chain fatty acids

When microbes in the gut break down food, they produce short-chain fatty acids (SCFAs). SCFAs produced in the gut include acetate, butyrate, and propionate. SCFAs play a key role in regulation of appetite, nourishment of other types of bacteria in the microbiome, healthy inflammatory balance, regulation of the immune system, and are the primary fuel for the cells that make up the lining of the large intestine.

A healthy gut lining is integral to good health because it serves as the gatekeeper for what gets through your digestive tract and into the rest of your body. It decides what good stuff gets through and what bad stuff makes its way to the nearest exit.

An unhealthy gut lining allows bacteria, toxins, and partially digested food to make its way out of your gut and into your body to wreak havoc. This condition – known as “leaky gut” – leads to imbalanced levels of inflammation in the gut, a disruption of normal microbiome balance, and can contribute to food sensitivities.

Polyphenol compounds serve a major role in microbial health by assisting the microbiome’s use of SCFAs.* When polyphenols aren’t present in the gut environment, more SCFAs are eliminated in the stool so they aren’t available to provide the benefits they otherwise could for a healthy gut.

Promotion of gut microbiome balance

Clinical evidence suggests that polyphenols support the balance of the gut microbiome by helping to alleviate growth of pathogenic phyla and regulating healthy commensal bacteria.*

Different types of polyphenols can either inhibit the growth of, or reduce the population of, many different problematic species in the gut, including multiple foodborne organisms and phyla associated with poor health outcomes.* Polyphenols can mitigate these “bad guys” by disruption of biofilms, starving out their food supply, or promoting growth of other commensal species to crowd them out.*

Conversely, many studies show certain polyphenols facilitate the growth of probiotic species in the gut such as Lactobacillus and Bifidobacteria.* In addition to promoting growth of good bacterial phyla, polyphenols contribute to a healthy mucus layer of the gut lining.*

Polyphenols can chain together to improve this physical mucus layer, which contributes to the integrity of the gut lining overall, as well as provide a favorable layer for adhesion and nourishment of healthy microbes.*

Reduction of the ratio of Firmicutes to Bacteroides

Intestinal bacteria imbalance has been shown to be a trigger for obesity in both humans and animals. Recent studies show that higher ratios of the phyla Firmicutes and Bacteroides are correlated with increased body weight; whereas, reduced Firmicutes-to-Bacteroides ratios are associated with improved glucose levels, less fat accumulation, and decreased body weight.

Polyphenols help balance this ratio, which promotes metabolism and therefore healthy weight management.* Polyphenols have shown potential in various clinical studies as possible “metabolic prebiotics” by beneficially reshaping the composition of gut microbial balance.*

A delicate interplay

Not only do polyphenols promote a healthy microbiome, but a healthy microbiome helps utilize polyphenols more efficiently, and a greater utilization of polyphenols promotes the presence of healthy microbes.* The greater the variety of polyphenols consumed, the greater the benefit derived from their consumption.

A large variety of fruits, vegetables, spices, and herbs in your diet enriches your gut with a rainbow of beneficial polyphenols that support healthy glucose metabolism, promote weight management, enhance healthy immune and neurotransmitter functions, and boost the health of the intestinal lining.*