The health benefits of live microbes, foods such as yoghurt, other fermented foods and raw fruits and vegetables include improved blood pressure and weight

It has been widely acknowledged that live microbes contribute to health, but convincing evidence has been lacking until now.

For the first time, a study from a group of scientists led by the International Scientific Association for Probiotics and Prebiotics (ISAPP) has provided real-world evidence that higher consumption of live microbes may promote health.

The research team classified over 9,000 individual foods listed in the US National Health and Nutrition Examination Survey (NHANES) into three categories based on their abundance of live microbes.

It then used NHANES participants’ reported food intake to quantify food containing medium or high levels of microbes. They then determined how these intakes correlated with various health markers, such as blood pressure and weight.

A health food unique to Japan made by the action of microorganisms. Make intestinal bacteria.
Image: © Yuuji | iStock

Increased consumption of live microbes linked to better health

Scientists found that increased consumption of live microbes in the diet was linked with multiple measurements of better health, including:

  • More favourable blood pressure
  • Better blood glucose and insulin
  • Lower inflammation
  • Lower waist circumference and body mass index

The research team was, therefore, able to establish that those who consumed higher quantities of live dietary microbes showed tangible if modest, health benefits.

Researchers could not confirm that the live microbes directly caused health benefits

Although the scientific approach did not allow researchers to conclude that the live dietary microorganisms directly caused the health benefits, the results do point to the argument that a diet that includes live microbes can, in a general sense, benefit health by increasing the diversity of microbes in the gut and by supporting immune function.

For example, in the past century, there has been a downward trend in the number of fermented foods in the diet and an upward trend in the consumption of processed foods.

As a result, there has been a dramatic reduction in the number of microbes most people consume daily.

However, the good news is that the dietary data shows that U.S. adults have gradually increased their live microbe consumption over the 18-year study period. This bodes well for the general health of the U.S. population.

More research must be carried out to explore further the health benefits of live microbes

”Although the dose-response associations we found were relatively modest, it was notable that these estimated benefits applied to several plausible and important health outcomes and were robust to adjustment for available confounders, including body mass index,” says co-lead author Prof. Dan Tancredi, PhD, of University of California – Davis.

“More research that extends these findings to other populations and research that uses study designs that permit stronger causal claims is needed, especially given the potential benefits that might be available by simply substituting into the diet more foods that have safe live microbes.”

ISAPP Executive Science Officer Mary Ellen Sanders, PhD, points out that the research is analysing all microbes in foods, not just probiotics. So this includes environmental microbes associated with raw fruits and vegetables and lactic acid bacteria associated with fermented foods. Thus, this study differs from probiotic research, as it focusses on microbes defined to the strain level, specific dose and proven health benefits.

Co-first author Prof. Colin Hill, PhD, of University College Cork, Ireland, says it’s possible that dietary advice of the future could include a recommendation for the daily consumption of high levels of live dietary microbes.

“Those foods with high levels of microbes (fermented foods, raw vegetables and fruits) are all nutritionally valuable parts of a healthy and diverse diet,” he explains.

“Secondly, these same foods could be providing an additional, hitherto unrecognised, health benefit due to live microbes themselves that enter the gut and interact with the host microbiome, immune system and even the enteric nervous system”.


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