The surprising source of your gut bacteria? It could be your next salad!

We've all heard "an apple a day keeps the doctor away." But what if that crunchy fruit is also feeding an invisible world inside you? New research ¹ has uncovered that when we bite into apples, carrots, and other fresh produce, we may be delivering microbes that seed our gut ecosystems, comprising the vast community of bacteria residing in our intestines.

Scientists from The Institute of Environmental Biotechnology ² in Austria have discovered a surprising new link between the fruits and vegetables we eat and the bacteria residing in our intestines. This new research has found that many types of gut bacteria actually originate from fresh produce, migrating to our digestive systems when we eat fruits, veggies and other plant foods.

By examining bacterial DNA, the researchers identified dozens of genera of bacteria that live both on produce and inside human intestines. These microbes make up a small but significant proportion of our gut ecosystems – on average close to 2% of an individual's unique gut bacteria come from fruits and vegetables.

This figure is higher among younger children and people who eat more vegetables. Although relatively few in number, these produce-derived bacteria provide health-promoting short-chain fatty acids (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) , vitamin B12 and vitamin K. 

More Plant Diversity, More Gut Diversity

The study also showed links between produce consumption and gut health. Eating over 10 different types of fruits and vegetables weekly was associated with a greater diversity of gut bacteria compared to a less varied plant diet. People who ate more vegetables tended to have a greater variety of gut microbes.