Bacteria are recognized as beneficial for their benefits to the body. Our digestive tract is home to no less than 10,000 billion bacteria that help us digest and contribute to the proper functioning of our body, in particular through the immune defences. This microcosm is more commonly called the intestinal flora or the intestinal microbiota.
Scientists are studying the links between the imbalance of the intestinal flora and certain pathologies, in particular autoimmune and inflammatory diseases. But for the first, American researchers studied the amount of live bacteria that we eat at each meal, depending on the food eaten.
Living microbes: more or less dense foods
“There is strong evidence that probiotics, defined as ‘live microorganisms which, when administered in adequate amounts, confer a health benefit to their host‘, are capable of affecting intestinal and systemic diseases and conditions”, detail the authors of the study. “However, the links between human health and live microorganisms ingested in the whole diet have not yet been directly studied.”
Through their work, the results of which have been published in The Journal of Nutrition Nutritional Epidemiologyso scientists have categorized foods into three categories, according to their bacterial density :
- those to low density with a maximum of 104 live bacteria / g: sodas, alcohols, pasteurized products, etc.;
- those to medium density with 104 to 107 live bacteria/g: pickles, fresh vegetables and fruits, etc.;
- those to high densityi.e. with more than 107 live bacteria / g: fermented milk products, most cheeses, kimchi, olives, tzatziki, etc.
People consume more live bacteria than 20 years ago
Using this classification of foods, the scientists “sought to estimate the intake of food bacteria in children aged 2 to 18 and in adults over 19 residing in the United States”. In total, 74,466 children and adults participated in the analysis. It should be noted that the participants all reside in the United States and therefore reflect the eating habits of this country.
“The fraction of children/adolescents (2-18 years old) consuming food containing live microbes increased significantly from 2001-2002 to 2017-2018” for food categories with high and medium density of live bacteria.
Specifically, the scientists noted that per capita consumption of foods moderately high in bacteria was estimated to be between 85 and 127 grams per day, a rather “low” figure according to them, “despite consumer interest in fermented foods”. These results would indicate that “the average diet lacks consistent sources of fermented foods”.
Nevertheless, the authors point out that further studies are needed in order to “further elucidate the role that food microbes play in health” which can help them get closer “to the development of dietary recommendations based on the science of living microbes”.