How Diet Affects our Gut Health

July 9, 2020
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The importance of gut microbiome to overall health has become abundantly clear in recent years. A number of factors, such as environment, genetics, and diet, influence the make-up of the gut microbiome. The contribution of each of these things is still being explored, but a study published last year by the Dan Knights lab at the University of Minnesota – frequent collaborators of the Khoruts lab – found that diet accounts for nearly 50% of the variation observed in the gut microbiome. This finding, that diet has a significant impact on gut microbiome, underscores the importance of diet specifically in maintaining gut microbiome health.

Given the plethora of proposed diets on the market making sense of what constitutes healthy eating can be overwhelming. Fortunately, as microbiome research becomes increasingly complex the basic tenets of a healthy diet are seemingly becoming simplified. The growing appreciation of the importance of gut microbiome to health, and the relationship between the food we eat and the gut microbiome, provides an amazing opportunity to simplify diet advice.

In general, the diet that seems to support what we understand to be a healthy gut microbiome appears to be a high-fiber diet pattern. Unfortunately, the average fiber intake in the United States consistently falls well below recommendations (approximately 10 grams/day vs the approximately 30 grams/day recommended). One of the most pronounced changes that occurs with transition to a low-fiber or “western” diet tends to be a loss of a variety of fiber-degrading bacteria (such as Prevotella strains). These fiber-degrading bacteria tend to be what are considered “good” gut bacteria, but our diets often don’t support these. An excellent illustration of this can be found in the video “Gut Microbiome Health.

Finally, don’t forget to include a variety of foods to increase fiber intake. In the same study referenced at the beginning of this article, dietary diversity was positively associated with microbiome stability.

So, a healthy diet from the standpoint of the gut microbiome is as simple as eating a variety of fiber containing foods such as fruits, vegetables, nuts/seeds, and whole grains (e.g. oats, whole wheat pasta/bread, brown rice, or quinoa), and introducing some plant-based protein sources (e.g. lentils or beans) into your diet. Using the “plate-method”, where half of your plate is fruits/vegetables, one-quarter of the plate is whole-grains or resistant starch (e.g. potatoes), and one-quarter of the plate is protein, is an effective way to quickly modify portions for gut microbiome health.