Scientists may have found the reason why “an apple a day keeps the doctor away” – millions of bacteria. Within an apple, there are 100 million beneficial bacteria that subsequently colonize your gut after you eat it.
Many of the microbes are important in maintaining a healthy microbiome (or gut environment), said Prof Gabriele Berg from Graz University of Technology, Austria, one of the researchers and authors of the study. She said:
The bacteria, fungi and viruses in our food transiently colonize our gut. Cooking kills most of these, so raw fruit and veg are particularly important sources of gut microbes.
As part of the study, the researchers compared organic vs. non-organic apples that visually appeared the same. They dissected each apple into all its parts – stem, peel, flesh, seeds, and calyx (the straggly bit at the bottom where the flower used to be) – and analyzed each part individually.
They found that organic and conventional apples both carried a similar number of bacteria but the organic apples harbored a more diverse and balanced bacterial community. They believe this could be why organic apples are more delicious and may be healthier than conventional apples. They also found that the core and seeds carry the majority of the bacteria so it’s best to eat the entire fruit. The study was published in the journal Frontiers in Microbiology.
The microbial diversity of bacteria in organic apples is why they are healthier because variety in the microbiome is thought to be key to a healthy gut. Berg explained:
Freshly harvested, organically managed apples harbor a significantly more diverse, more even and distinct bacterial community, compared to conventional ones. This variety and balance would be expected to limit overgrowth of any one species, and previous studies have reported a negative correlation between human pathogen abundance and microbiome diversity of fresh produce.
Meaning that the more varied your diet, the fewer harmful bacteria are found.
Another fun discovery was how organic apples carried significantly higher quantities of a microbe known as methylobacterium, which is known to boost strawberry-flavored compounds. This would explain why people say they can taste a difference between organic and ordinary produce.
The next phase of their study will be “to confirm to what extent diversity in the food microbiome translates to gut microbial diversity and improved health outcomes,” said Birgit Wassermann, also at Graz University of Technology and the lead author of the study. She said that it would be a good idea to put this sort of information on supermarket food labels:
The microbiome and antioxidant profiles of fresh produce may one day become standard nutritional information, displayed alongside macronutrients, vitamins and minerals to guide consumers.
