Study uncovers strong links between a person's diet, gut microbes and health

Reviewed by Emily Henderson, B.Sc.Jan 11 2021

Diets rich in certain plant-based foods are linked with the presence of gut microbes that are associated with a lower risk of developing conditions such as obesity, type 2 diabetes and cardiovascular disease, according to recent results from a large-scale international study that included researchers from King's College London, the Harvard T.H. Chan School of Public Health, Massachusetts General Hospital (MGH), the University of Trento, Italy, and health science start-up company ZOE.

Key takeaways

• The largest and most detailed study of its kind uncovered strong links between a person's diet, the microbes in their gut (microbiome) and their health.
• International study uses metagenomics and blood chemical profiling to uncover a panel of 15 gut microbes associated with lower risks (and 15 with higher risks) for common illnesses such as diabetes and heart disease.
• Some of the identified microbes are so novel that they have not yet been named.
• These findings could be used to provide personalized dietary advice for better health, based on gut microbiome testing.

The PREDICT 1 study analyzed detailed data on the composition of participants' gut microbiomes, their dietary habits, and cardiometabolic blood biomarkers. The researchers found evidence that the microbiome is linked with specific foods and diets, and that, in turn, certain microbes in the gut are linked to biomarkers of metabolic disease. Surprisingly, the microbiome has a greater association to these markers than other factors, such as genetics. Their report, authored by Dr. Francesco Asnicar (University of Trento) and Dr. Sarah Berry (King's College London) and coordinated by Tim Spector (King's College London) and Nicola Segata (University of Trento), appears in Nature Medicine.

As a nutritional scientist, finding novel microbes that are linked to specific foods, as well as metabolic health, is exciting. Given the highly personalised 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, Reader in Nutrition Sciences, King's College London

For example, the findings reveal that having a microbiome rich in Prevotella copri and Blastocystis species was associated with maintaining a favorable blood sugar level after a meal. Other species were linked to lower post-meal levels of blood fats and markers of inflammation.

Professor Tim Spector, Epidemiologist from King's College London, who started the PREDICT study program and is scientific founder of ZOE explains, "When you eat, you're not just nourishing your body, you're feeding the trillions of microbes that live inside your gut."

Researchers also discovered that the makeup of subjects' gut microbiome was strongly associated with specific nutrients, foods, food groups and overall diet composition. The researchers found robust microbiome-based biomarkers of obesity, as well as markers for cardiovascular disease and impaired glucose tolerance, which are key risk factors for COVID. These findings can be used to help create personalized eating plans designed specifically to improve one's health.

"I am very excited that we have been able to translate this cutting edge science into an at-home test in the time it has taken for the research to be peer reviewed and published," says Spector. "Through ZOE, we can now offer the public an opportunity to discover which of these microbes they have living in their gut. After taking ZOE's at-home test, participants will receive personalized recommendations for what to eat, based on comparing their results with the thousands of participants in the PREDICT studies. By using machine learning, we can then share with you our calculations of how your body will respond to any food, in real-time through an app."

The researchers found in subjects who ate a diet rich in healthy, plant-based foods were more likely to have high levels of 'good' gut microbes. Conversely, diets containing more highly processed plant-based foods were more likely to be associated with the 'bad' gut microbes.

"We were surprised to see such large, clear groups of what we informally call 'good' and 'bad' microbes emerging from our analysis," affirmed Nicola Segata, PhD, professor and principal investigator of the Computational Metagenomics Lab at the University of Trento, Italy and leader of the microbiome analysis in the study. "It is also exciting to see that microbiologists know so little about many of these microbes that they are not even named yet. This is now a big area of focus for us, as we believe they may open new insights in the future into how we could use the gut microbiome as a modifiable target to improve human metabolism and health."

PREDICT 1 was an international collaboration to study links between diet, the microbiome, and biomarkers of cardiometabolic health. The researchers gathered microbiome sequence data, detailed long-term dietary information, and results of hundreds of cardiometabolic blood markers from just over 1,100 participants in the U.K. and the U.S. PREDICT 2 completed its primary investigations in 2020 with a further 1,000 U.S participants, and PREDICT 3 launched a few months ago.