02 Apr Gut feelings: The new era of dietary recommendations
April 1, 2019
A growing number of research studies are linking the microbiome to multiple diseases. Having the right balance of different species of bacteria is critical for good health. But, what happens when it gets out of whack? That’s what scientists are currently teasing apart. For example, we’ve learned that excess Methanobrevibacter smithii and Methanobacterium ruminatum leads to constipation. We also know that high levels of Akkermansia muciniphila are at least partially responsible for the success of dietary intervention in patients battling obesity.
What we eat also plays a critical role in our health, but it involves the gut microbiome more than you may have appreciated.
In studying how the microbiome affects our health, scientists have made interesting discoveries about common ingredients in our food. Have you seen polysorbate 80 or carboxymethylcellulose on ingredient lists? They are both common emulsifiers in processed foods like ice cream. A diet high in emulsifiers is related to chronic inflammatory diseases. Pro-inflammatory markers increase when more emulsifiers are consumed. This is probably due to effects on the gut microbiome. There is more infiltration of the mucus layer that protects that lining of the intestine, which can lead to chronic colitis. Chronic colitis is more common under these conditions if there is a genetic predisposition. Without the genetic risk for colitis, low-grade intestinal inflammation sets in as well as symptoms of metabolic syndrome, like hyperglycemia and increased body weight. The different responses to emulsifiers isn’t all about genetics though. One study showed that a certain degree of diversity in the microbiome is required to trigger inflammation.
The variety of microbes is also implicated in inflammatory bowel disease (IBD). IBD is multifactorial, making the effects of interventions highly variable. Studies have demonstrated that people who eat high fiber diets loaded up with fruits and vegetables are less likely to develop IBD than people whose diets primarily consist of meats, fish, eggs, nuts, and seeds, which are high in polyunsaturated fatty acids and omega-6 fatty acids. This difference is likely related to how different bacterial strains react to different foods. Take maltodextrin for example. It is extremely common in processed foods and increases biofilm. Eliminating maltodextrin from the diet may help many people with Crohn’s disease, but only if they also have adherent-invasive Escherichia coli bacteria in their gut that makes the biofilm.
As we move into the next phase of microbiome studies, we will see more connections between what we eat, how we eat, specific bacterial strains, and health and disease. Doctors are already using information about the gut microbiome to more effectively treat cancer patients undergoing immunotherapy. It’s only a matter of time before information about an individual’s microbiome can be applied more broadly to general dietary recommendations. Stay tuned to the ETP blog for the latest updates in this exciting time of precision nutrition!
If you’re interested in the scientific details, check out the following scholarly article.
Viennois E, Gewirtz AT, Chassaing B. Chronic Inflammatory Diseases: Are We Ready for Microbiota-based Dietary Intervention? Cell Mol Gastroenterol Hepatol. 2019 Mar 2. pii: S2352-345X(19)30024-4.