"All disease begins in the gut" ~ Hippocrates
The discovery of the microbiome and the functions of all the microbes within our body has been equally as important as the discovery of the human genome. The microbiome protects us against germs, breaks down food to release energy, and produces vitamins. When it comes to supporting gut health, much of the emphasis has been placed on probiotics, the good bacteria known to have specific benefits on the digestive tract.
An imbalance in the good and bad bacteria in the digestive system can show up in a wide array of systemic conditions, including hormonal issues, metabolic dysfunction, depression, cognition, even some cancers. It is recommended we take probiotic supplements, eat yogurt, sauerkraut, kimchi, and sourdough bread to flood the GI tract with good microbes. However, for these bugs to function optimally in our favor, they need to feed on substrates called prebiotics.
Think of prebiotics as fertilizer for our microbiome. They are what probiotics feed on; in fact, we cannot fully digest these dietary fibers without good bacteria. Prebiotics and probiotics live in symbiosis. We need good bacteria to utilize the fiber we get from food and we equally need prebiotics to maintain the balance of good and bad bacteria in the GI tract. Research has shown that in healthy individuals, the more prebiotic foods we eat, the more good bacteria can proliferate, including Lactobacillus rhamnosus GG, L. reuteri, bifidobacteria, and certain strains of L. casei or the L. acidophilus-group.1
Most commonly we think of prebiotic foods to include onions, garlic, jerusalem artichokes, asparagus and plantains. But there are many more prebiotic foods to include and enjoy on a daily basis. Think polyphenols, the magical bioactive compounds found in a colorful, plant-rich diet. Polyphenols are found in fruits, vegetables, nuts, seeds, grains, and olive oil. Prebiotics also include herbs, cacao, sea vegetables, green tea, raw honey, and colostrum.
The greatest health benefit from including more prebiotic foods is better digestion*. As the gut bacteria metabolizes these undigested fibers, they produce short chain fatty acids (SCFA), which play a critical role in colon health. One of the SCFA's, butyric acid, protects the health of the intestinal lining. Others regulate electrolytes which are important for proper digestions, produce bowel movement, and prevent diarrhea.
More benefits of prebiotics:
Improves immunity and reduce inflammation
Can protect against gut infection and gut permeability
Improved GI symptoms
Builds stronger bones by increasing absorption of calcium
Improved mental health from positive modifications to microbiome
Protective role in insulin resistance, diabetes and obesity
Better hydration in the body 2
*Since prebiotics feed bad bacteria as well as good bacteria, they can cause bloating, gas, diarrhea, and constipation.
A note of caution for people doing a restrictive diet or elimination diet that may limit prebiotics. These diets are meant to be followed for a limited time. I see people in my practice stay on these diets for far too long. In cases where prebiotics are limited or not allowed, like on a low FODMAP diet, the pendulum swings the other way in their gut health. The lack of plant diversity in the diet shifts the microbiome, causing dysbiosis or exacerbating it. It is important to work with a nutrition professional who can properly assess your response to prebiotic foods and assist in the reintroduction of these dietary fibers.
Markowiak, P., Śliżewska, K., Effects of Probiotics, Prebiotics, and Synbiotics on Human Health. Nutrients. 2017 Sep 15;9(9)