Landmark study reveals 1 factor links gut health and long life

Beneath the surface of the skin lies a vast internal ecosystem. About 100 trillion microorganisms — a mixture of bacteria, viruses, fungi, and protozoa— call the gut home.

In the largest and most detailed study of its kind to date, researchers explore how this gut microbiome is linked to diet and disease. The team discovered specific microbes associated with diet are associated with biomarkers of obesity, type 2 diabetes, and cardiovascular disease.

The study suggests adjusting your diet to support your gut microbiome may be pivotal for long and healthy life.‌‌

The findings, which may empower people to take control of their gut health, were published Tuesday in the journal Nature Medicine.

"Our findings show how little of the microbiome is pre-determined by our genes and therefore how much is modifiable by diet," study co-author Sarah Berry tells Inverse. Berry is a researcher at King's College London.

The study also shows that it's possible to manipulate the microbiome through diet and in turn, achieve meaningful health outcomes, Berry adds.

LONGEVITY HACKS is a regular series from Inverse on the science-backed strategies to live better, healthier, and longer without medicine. Get more in our Hacks index.

HOW THIS AFFECTS LONGEVITY — In the past decade, a surge of studies centered around the relationship between the human microbiome and longevity. However, what was missing was a robust exploration of this link in a large diverse group.

To fill this research gap, scientists launched the PREDICT 1 study and analyzed the gut microbiomes, dietary habits, and cardiometabolic blood biomarkers of 1,098 participants. PREDICT 1 is part of an international research project on personalized nutrition, composing one of the richest datasets in the world on individual responses to food.

The group gave stool and blood samples and answered surveys. Researchers documented participants' body fat, blood sugar levels in response to food, physical activity, and sleep.

After analyzing the massive dataset, researchers discovered that people's microbiome composition differed based on what they ate. Diet determined the make-up of the microbiome more than other factors, like genes.

"While one cannot change their genetics, one can definitely modulate their gut microbiome."

The researchers found that participants who consumed lots of healthy, minimally processed plant-based foods had higher levels of beneficial gut microbes. An abundance of these "favorable" gut microbes was associated with a lower risk of developing conditions such as obesity, type 2 diabetes, and cardiovascular disease.

Specifically, 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.

Inversely, people who are more processed foods — those full of sugar, salt, and chemical additives, and low in fiber — had vastly different microbes, colloquially called "bugs," living in their gut.

The team identified a "clear, pronounced, and novel" segregation of bugs according to their favorable and unfavorable associations with foods, Berry explains.

The trends they found were so consistent, the researchers believe that their microbiome data can be used to determine the risk of cardiometabolic disease among people who do not yet have symptoms, possibly to prescribe a personalized diet designed specifically to improve someone's health.

WHY IT'S A HACK — Evidence suggests the gut microbiome is influenced by every single meal. This study suggests tailoring your diet to support specific "good" microbes and diminish "bad" ones.

There isn't a single, detrimental microbe that will destine a person to develop disease or die early. Additionally, there isn't a "good" microbe that's a silver bullet for longevity.

Instead, there are at least 15 favorable and unfavorable microbial clusters that sway health outcomes.

Ultimately, the fact that the microbiome is linked with certain metabolic markers is "very good news," study co-author Nicola Segata tells Inverse. Segata is a researcher at the Centre for Integrative Biology at the University of Trento.

"While one cannot change their genetics, one can definitely modulate [especially via diet] their gut microbiome," Segata says. "This can give more hope for therapeutic or prevention strategies that can indeed be very effective and do not require complex or potentially dangerous treatments."

SCIENCE IN ACTION — Based on these findings and other growing evidence, it's crucial to understand that "your biology and gut microbes are unique," study co-author Tim Spector tells Inverse. Spector is a genetic epidemiologist at King's College London.

"You have to work out for yourself what foods best suit your body and your microbes," Spector advises.

"You have to work out for yourself what foods best suit your body and your microbes."

One way to do this is by testing your microbiome using tests at home or at your doctor's office. The researchers suggest utilizing the gut health program they developed with the digital health company Zoe Global harnessing the study's findings. The program combines an individual's specific microbiome composition with PREDICT studies' data to design personalized recommendations for what to eat. (A number of the study authors are consultants to Zoe Global or are/have been employees of Zoe Global.)

"In the meantime, you can hedge your bets and try foods that are good for your gut, such as diverse plants, high fiber, fermented foods, avoiding ultra-processed foods, and above all plenty of variety," Spector says.

Like so much in health, there's no "one-size-fits-all" solutions, especially when it comes to the gut microbiome.

"This is just the beginning and we will soon have ten times the data linking microbes and food to provide even better advice," Spector says.

HACK SCORE OUT OF 10 — 🍉🌶🥕🥦🥬🥑 🌽(7/10 diverse, gut-health supportive foods.)

Abstract: The gut microbiome is shaped by diet and influences host metabolism; however, these links are complex and can be unique to each individual. We performed deep metagenomic sequencing of 1,203 gut microbiomes from 1,098 individuals enrolled in the Personalised Responses to Dietary Composition Trial (PREDICT 1) study, whose detailed long-term diet information, as well as hundreds of fasting and same-meal postprandial cardiometabolic blood marker measurements were available. We found many significant associations between microbes and specific nutrients, foods, food groups and general dietary indices, which were driven especially by the presence and diversity of healthy and plant-based foods. Microbial biomarkers of obesity were reproducible across external publicly available cohorts and in agreement with circulating blood metabolites that are indicators of cardiovascular disease risk. While some microbes, such as Prevotella copri and Blastocystis spp., were indicators of favorable postprandial glucose metabolism, overall microbiome composition was predictive for a large panel of cardiometabolic blood markers including fasting and postprandial glycemic, lipemic and inflammatory indices. The panel of intestinal species associated with healthy dietary habits overlapped with those associated with favorable cardiometabolic and postprandial markers, indicating that our large-scale resource can potentially stratify the gut microbiome into generalizable health levels in individuals without clinically manifest disease.