The global trend of increasing meat intake is being countered by a rise in plant-based, vegetarian, and vegan diets in some regions. People are making the switch from meat for various reasons, including concerns about the impact of animal products on human health and the health of the planet. Recent research published in Nature Microbiology sheds light on how following a vegan or vegetarian diet can impact gut bacteria.
The study analyzed poop samples from over 21,000 participants in the United Kingdom, United States, and Italy, who provided detailed information about their diets. The researchers found that vegans had the healthiest diets, followed by vegetarians and then omnivores based on the Healthful Plant-Based Diet Index (hPDI). However, when it comes to gut microbiome health, the results were surprising.
Although vegans and vegetarians had lower species richness in their gut microbiomes compared to omnivores, their microbiome compositions were significantly different. Each dietary pattern had its own microbial signature, with omnivores having more bacteria associated with meat consumption and inflammation, while vegans had more fiber-fermenting bacteria and bacteria producing beneficial short-chain fatty acids.
The study also found that the gut microbiomes of vegans were healthier than those of vegetarians, and vegetarians’ gut microbiomes were healthier than omnivores. The researchers identified specific bacteria associated with cardiometabolic health markers like body mass index, blood pressure, and blood fats, with omnivores showing fewer species of “good” bacteria and more species of “bad” bacteria compared to vegans and vegetarians.
The researchers also discovered that the transfer of bacteria from food to gut microbiome differed between dietary patterns, with dairy-associated bacteria more prevalent in omnivores and vegetarians, but not in vegans. On the other hand, bacteria associated with fruits and vegetables were more common in vegans.
In conclusion, the study highlights the strong influence of dietary patterns on gut microbiome composition and specific gut microbes associated with better health. Vegans, in particular, had a microbiome composition linked to better health, with higher numbers of bacteria producing beneficial short-chain fatty acids. The findings suggest that greater consumption of healthy plant-based foods in vegetarians and omnivores could lead to a microbiome composition associated with better health. Further research is needed to explore the potential health benefits of plant-based diets on gut bacteria.