The Microbiome and Diseases

One ecosystem, dozens of diseases

There's strong evidence that the gut microbiome plays a role across many different conditions, not just one or two. A large genetic study looked at health data from 422,417 people, searching for conditions significantly linked to gut bacteria genetics. High blood pressure came through as one clear connection. So did COPD, allergic conditions, body weight, and blood fat levels. Researchers even traced some of these links down to specific bacteria. One, called Ruminococcus flavefaciens, showed a possible role in high blood pressure. Another, called Clostridium, showed a possible role in platelet count, part of how blood clots. This is just one study, using one method. The rest of this page shows how much wider the picture actually gets.

Source: PMC, Human genetic determinants of the gut microbiome and their associations with health and disease

More genes than stars in the sky

A Harvard Medical School team studied DNA-sequencing data from the human gut and mouth. They estimated that the full collective microbial gene pool may be larger than the number of stars in the observable universe. In a separate project, the same team combined data from over 2,500 patient samples. They ran 67 million statistical models to find which microbial features most reliably predicted seven different diseases. These features included specific species, specific genes, and specific chemical pathways. The genes themselves, not just which bacteria were present, turned out to be the strongest predictor.

Source: Harvard Gazette, Study links genetic makeup of bacteria in the human gut to several diseases

A growing, searchable map

Researchers have built a database called GMMAD to track all of this. It currently catalogues 3,836 documented links between diseases and gut microbes, and 879,263 links between microbes and the chemical compounds they produce. Using these links, GMMAD has predicted a further 220,690 possible connections between gut microbe compounds and disease, across 113 different diseases in total.

Some of these connections are already well understood on their own. One gut bacterium, Fusobacterium nucleatum, has been shown to help colorectal cancer spread to other parts of the body. A compound made by gut bacteria, called TMAO, has been widely linked to cardiovascular disease. A related compound, PAGln, has been tied to a higher risk of heart attack and stroke, by making blood platelets more likely to clump together.

Source: PMC, GMMAD: a comprehensive database of human gut microbial metabolite associations with diseases

What this means for you

You don't need to memorise specific bacteria names to benefit from this research. Here's why plant foods keep coming up as the recommendation: different plants feed different bacteria. A study of over 10,000 people found that eating more than 30 different plant types a week was linked to a more diverse gut microbiome than eating 10 or fewer. Since the research above ties a more diverse, well-fed microbiome to a lower risk across several of these conditions, eating a wider variety of plants is the most evidence-backed habit available, alongside proper medical care, not instead of it. This is the exact principle GutLab is built around: regularly feeding the microbiome a broad range of plant-rich ingredients.

Explore diseases and the microbiome on this page

Use the panels on this page to explore how the microbiome connects to specific body systems and conditions, from digestion and skin to hormones, the brain, and beyond. Each category looks at what the current research actually shows for that area, using real studies rather than general claims.