More evidence that plant-based diets help improve gut bacteria

A plant-based diet has been shown to correlate with important gut microbes that play a key role in lowering the risks of diseases like obesity, cardiovascular disease, and Type-2 diabetes, according to a recent study. The study was conducted on an international scale by Harvard-affiliated Massachusetts General Hospital (MGH) and was co-authored by Andrew T. Chan.

A Clear Link

“This study demonstrates a clear association between specific microbial species in the gut, certain foods, and risk of some common diseases,” says Chan in a statement. Chan is chief of the Clinical and Translational Epidemiology Unit at MGH, a  gastroenterologist, and a professor of medicine at Harvard Medical School.

PREDICT 1, or Personalized Responses to Dietary Composition Trial 1, was a metagenomic study that examined the data on participants’ dietary habits, the composition of their microbiomes, and cardiometabolic blood biomarkers. Strong evidence associates certain foods and diets with a healthy microbiome. Evidence also revealed that the composition of the microbiome is coupled with metabolic biomarkers of disease.

“Studying the interrelationship between the microbiome, diet, and disease involves a lot of variables because people’s diets tend to be personalized and may change quite a bit over time,” says Chan. “Two of the strengths of this trial are the number of participants and the detailed information we collected.” Over 1,100 participants from both the U.K. and the USA were involved in the international study.

You Are What You Eat

Participants who ate a healthy plant-based diet had higher levels of certain gut microbes that can help prevent disease. Potent biomarkers of impaired glucose intolerance, obesity, and cardiovascular disease were also found. “When you eat, you’re not just nourishing your body, you’re feeding the trillions of microbes that live inside your gut,” says Tim Spector. Spector is an epidemiologist at King’s College London and the founder of the study.

Prevotella copri and Blastocystis are gut bacteria species that can help the body maintain healthy blood sugar levels after a meal. Other bacteria were found to be related to lower levels of inflammation after a meal. In fact, the results were so consistent that scientists believe the data can be used to analyze the risk of cardiometabolic disease, even among those who don’t show symptoms. 

“We were surprised to see such large, clear groups of ‘good’ and ‘bad’ microbes emerging from our analysis,” says Nicola Segata. Segata is a professor and chief investigator at the Computational Metagenomics Lab at the University of Trento, Italy. “And it is intriguing to see that microbiologists know so little about many of these microbes that they are not even named yet.”

Co-senior author Curtis Huttenhower co-directs the Harvard T.H. Chan Microbiome in Public Health Center. “Both diet and the gut microbiome are highly personalized. PREDICT is one of the first studies to begin unraveling this complex molecular web at scale,” says Huttenhower. 

“We hope to be able to use this information to help people avoid serious health problems by changing their diet to personalize their gut microbiome,” says Chan.

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