A plant-based diet lowers your risks of diabetes and heart disease by boosting healthy gut bacteria, study finds

• There's even more research that a plant-based diet is linked to a healthy microbiome, beneficial bacteria that live in the gut.
• Certain species of gut bacteria are linked to health outcomes like better blood sugar control, lower body fat, and a healthier heart.
• Researchers hope that analyzing a person's unique gut microbiome could lead to personalized recommendations on what to eat for optimal health.

Plant-based diets are linked to plenty of health benefits, and new evidence suggests it may be because they cultivate friendly bacteria in our gut that control blood sugar levels.

The study, published January 11 in Nature Medicine, is the largest and most detailed to date that looks at gut microbiome, diet, and health.

Researchers from multiple universities, including King's College London and the Harvard T.H. Chan School of Public Health, looked at extensive data from 1,098 health adults in the UK and the US, including long-term diet information, blood tests before and after eating, and samples of their poop to analysis gut bacteria.

They found close associations between certain diets, specific species of bacteria, and good health.

This information could help researchers develop ways for individuals analyze their own, unique gut microbiome, and use that analysis to develop a personalized eating plan. (Several of the study's authors have ties to ZOE, a health start-up that analyzes gut bacteria and recommends diets based on their results. )

"Given the highly personalized composition of each individuals' microbiome, our research suggests that we may be able to modify our gut microbiome to optimize our health by choosing the best foods for our unique biology," Dr. Sarah Berry, co-author of the study and reader in Nutrition Sciences at King's College London, said in a press release.

In the meantime, existing evidence supports this study's findings that the best route to a healthy gut, right now, a whole, plant-based diet.

Links between certain foods and types of 'good' bacteria

One species of bacteria, Prevotella copri, was associated with lower body fat, better blood sugar control, and good cardiovascular health. The researchers found that these bacteria were more common when people ate a diet high in polyunsaturated fat, found in fish, nuts, and seeds, although they weren't linked to specific foods.

Another type of bacteria, Blastocystis species, were also linked to stable blood sugar and a healthy metabolism, and were significantly less common in participants with obesity. This bacteria is controversial, and previous research is mixed on whether it may be considered to be a parasite, potentially linked to digestive issues.

Participants who had both of these types of bacteria had, on average, 17% less visceral fat.

Other types of beneficial bacteria were strongly correlated with a plant-based diet, high in foods like spinach, tomatoes, broccoli, and seeds.

To nourish your gut, eat your veggies and avoid processed food and added sugar

Plenty of research has already suggested that whole, unprocessed plant foods have major benefits for cultivating beneficial bacteria.

A 2019 study found that vegan diets are linked to weight loss and better metabolism in part because they're good for the gut microbiome. More research found that you can improve your health without going fully vegan by eating plenty of whole plant foods like veggies, fruits, whole grains, and nuts.

Evidence suggests that these benefits also apply to eating plans like the Mediterranean diet, which is also high in whole grains, vegetables, and fruits.

The key to growing a strong gut microbiome seems to be eating mainly nutrient-dense whole plant foods, but also steering clear of processed foods, refined starches and oils, and added sugar.

"These are all things that probably your grandparents told you," Dr. Rob Knight, professor at the University of California, San Diego, and co-founder of the American Gut Project, previously told Insider. "What's happening right now is we're trying to understand why those things are true."