Graz study on fruit and microbiomes proves: You are what you eat

2023-10-26 04:00:00

Fruits and vegetables influence the colonization of intestinal flora, particularly in the first three years of life.

You are what you eat: A team of researchers from Graz has succeeded for the first time in demonstrating a connection between fruit and vegetable consumption and the microbiome in the intestine. Wisnu Adi Wicaksono, Gabriele Berg and their colleagues from the Institute for Environmental Biotechnology at Graz University of Technology found in a meta-study that eating fruit and vegetables contributes positively to bacterial diversity in the human intestine, it said in a release on Tuesday.

The human microbiome, i.e. the entirety of all microorganisms that colonize the intestine, is largely transmitted to babies via the mother’s microbiome and passed on through breast milk. However, science has not yet been able to uncover any further sources, according to the TU in its release. The team around Wicaksono and Berg has now managed to do this. They examined the bacterial diversity in the intestine – especially plant microorganisms – and found that fruits and vegetables contribute to the human microbiome. The results of their meta-study were published in the journal Gut Microbes.

Specifically, the researchers were able to demonstrate that the frequency of fruit and vegetable consumption and the variety of plants consumed influence the amount of fruit and vegetable-associated bacteria in the human intestine. Early childhood in particular represents a time window for colonization with plant-associated bacteria. The microorganisms of plant origin have probiotic and health-promoting properties, which have also been demonstrated.

“We have now succeeded for the first time in proving that microorganisms from fruits and vegetables can colonize the human intestine,” explained lead author Wicaksono. This suggests that fruit and vegetables, especially in infancy, have a positive influence on the development of the immune system in the first three years of life, as the intestinal microbiome develops during this time. But even after that, a good diversity of intestinal bacteria is beneficial for health and resistance. “It simply influences everything. Diversity influences the resilience of the entire organism. Higher diversity conveys more resilience,” said institute director Berg.

For the meta-study, the team from Graz created a catalog with microbiome data from fruits and vegetables in order to be able to assign their bacteria. They compared this with publicly available data from two studies on intestinal flora. The TEDDY project looked at the development of babies using a long-term study and the American Gut Project studied the intestinal flora of adults – both projects also collected data on the subjects’ food intake. In total, the researchers had access to metagenome data from around 2,500 stool samples, each of which contained between one and ten million sequences – meaning several billion sequences were evaluated. This extensive data set was used to detect the presence of fruit and vegetable microflora in the intestine. According to the TU, this evidence is a crucial building block in proving the WHO’s “One Health” concept, which closely links the health of humans, animals and the environment.

Berg is now also working on the EU-funded HEDIMED project to further research the discovered connection. Together with international colleagues, an intervention study will involve people on three continents eating the same thing for a certain period of time and then analyzing their excretions.