We know that our gut microbes play pivotal roles in the health of not just the gut, but of all the other tissues of the body, including the brain. Now a key question is: how does our diet influence our microbes?
In this comprehensive review article, the authors provide an overview of the structure of the gut, gut microbes, and factors affecting gut health, with a focus on fats.
Key points
- Most of the cells in the gut lining use ketones for energy (which are famous now due to the ketogenic diet) derived from the short chain fat butyrate made by some gut microbes.
- The specific microbes that live in our guts depend to a large degree on what we eat, because basically that is what they get to eat.
- Beneficial microbes (such as those that make butyrate) need fiber, so the more fiber in the diet, the more of these microbes.
- Poor diets, such as the “Western Diet,” do not feed beneficial microbes, but changing the diet (to, for example, a Mediterranean, other traditional diet, or plant-based diet) can ameliorate the deficiencies. A probiotic may need to be taken at least initially to “repopulate extinct species.”
- Some microbes consume fats, and the amount and types of fats affect microbe populations. High levels of saturated fats tend to feed potentially pathogenic bacteria, which then outcompete the beneficial ones. Unsaturated fats seem to have the opposite effect in that they can feed the beneficial species (such as some Lactobacillus and Bifidobacteria species).
- High fat diets, especially if high in saturated fats, are risk factors for inflammatory bowel disease and colorectal cancer.