New research suggests that eating more foods rich in live microbes may help lower blood pressure and blood sugar levels, reduce inflammation, and help a person maintain a healthy weight.

Consuming healthy bacteria and fungi in fermented foods, yogurt, and some raw fruits and vegetables can help keep the gastrointestinal tract in working order. But these live microbes may also benefit health and wellbeing in other ways.

For example, bacterial species like Lactobacillus acidophilus (L. acidophilus) may improve insulin sensitivity, and Bifidobacterium bifidum (B. bifidum) has been shown to reduce gastrointestinal symptoms related to stress.

Because of the potential health benefits of live microbes, researchers from the International  Scientific Association for Probiotics and Prebiotics (ISAPP) questioned in a 2020 paper whether there should be a recommended daily intake of microbe-rich foods similar to the recommendations for fiber intake.

To examine this further, scientists conducted a study in 2022 to estimate the number of live microbes present in individual foods and how much of those foods Americans consumed. With that data in hand, the research team set out to determine whether eating foods rich in live microbes in general, not just probiotics, improved health and wellbeing.

The study, funded by the ISAPP and published in The Journal of Nutrition, used food consumption data from a nationally represented sample of 46,091 adults from the U.S. National Health and Nutrition Examination Survey (NHANES).

First, the research team determined the amount of food with moderate to high levels of microbes each participant consumed. Then, they examined how this intake impacted health markers like cholesterol and blood sugar levels.

After compiling the data, the scientists found that consuming foods with medium to high amounts of live microbes — such as yogurt and fermented foods — was associated with moderate health improvements, including a lower BMI and waist circumference. It was also associated with reduced blood pressure, plasma glucose, insulin, C-reactive protein, and triglyceride levels. In addition, the scientists found that eating microbe-rich foods may promote higher HDL (good) cholesterol levels.

According to the study authors, their findings suggest that adults who substitute 400 grams (about 14 ounces) of pasteurized, heat-treated, or highly processed foods with 400 grams of foods with medium to high amounts of live microbes may experience health benefits. These include reductions in systolic blood pressure from 1 to 4mm Hg and waistline reductions from about two-thirds of an inch to two inches.

“This dietary change could be accomplished […] by consuming 7 ounces of yogurt (200 g), one serving of fresh fruit (75 g), and one serving of fresh vegetables (125 g),” the authors wrote.

Still, there are limitations to the study. For example, the team says they cannot exclude the possibility that other foods without live microbes could have played a role in their findings. In addition, the participants self-reported their dietary intakes, which could lead to underreporting or over-reporting of food types. Moreover, individual overall eating patterns and food choices could have influenced some of the health parameters examined in the study.

Still, the scientists say that the results of their research provide preliminary evidence to support developing a recommended daily intake of foods with live microbes — much like the current daily recommendations for fiber.