03.17.23
A new study published in the Journal of Nutrition suggested that higher consumption of live microorganisms—including those found in fermented foods and raw fruits and vegetables—may promote overall health.
Scientists led by the International Scientific Association for Probiotics and Prebiotics (ISAPP) classified over 9,000 individual foods listed in the U.S. National Health and Nutrition Examination Survey (NHANES) into three categories based on their level of live microbes.
Researchers used reported food intake from NHANES participants (2001-2018; age 19+) to quantify the food they ate that contained medium or high levels of microbes. They then determined how these intakes correlated with health markers like blood pressure and weight.
Those who consumed higher quantities of live dietary microbes showed tangible, if modest, health benefits, researchers said.
In the past century, a reduction in the amount of fermented foods in the diet and increased consumption of processed foods has led to a dramatic reduction in the number of microbes most people consume on a daily basis.
However, dietary data used in the study showed U.S. adults have gradually increased their live microbe consumption over the 18-year study period. This may bode well for the health of the population, researchers said.
This study built on two previously published papers, which conducted the preliminary work necessary for this latest study: "Should There Be a Recommended Daily Intake of Microbes?" and “A Classification System for Defining and Estimating Dietary Intake of Live Microbes in US Adults and Children.”
“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,” said 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, noted the research focused not just on probiotics, but on all microbes in foods, including environmental microbes associated with raw fruits and vegetables as well as lactic acid bacteria associated with fermented foods. Thus, the study differs from probiotic research, which focuses 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, said it's possible that future dietary advice could recommend 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 said. “Secondly, these same foods could be providing an additional, hitherto unrecognized, 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.”
Researchers acknowledged that given analyses were of food intakes and not specifically microbe numbers, they could not exclude the possibility that other food components other than live microbes contributed to associated health parameters.
Scientists led by the International Scientific Association for Probiotics and Prebiotics (ISAPP) classified over 9,000 individual foods listed in the U.S. National Health and Nutrition Examination Survey (NHANES) into three categories based on their level of live microbes.
Researchers used reported food intake from NHANES participants (2001-2018; age 19+) to quantify the food they ate that contained medium or high levels of microbes. They then determined how these intakes correlated with health markers like blood pressure and weight.
Results
Increased consumption of live microbes (an additional 100-g intake) in the diet was associated with multiple measurements of better health, including:- More favorable blood pressure;
- Better blood glucose and insulin;
- Lower inflammation;
- Lower waist circumference and body mass index.
Those who consumed higher quantities of live dietary microbes showed tangible, if modest, health benefits, researchers said.
Analysis
While scientists couldn’t conclude from this study that live dietary microorganisms directly caused the health benefits, the results are consistent with arguments that dietary exposure to live microorganisms in general could benefit health by increasing the diversity of microbes in the gut or by supporting immune function.In the past century, a reduction in the amount of fermented foods in the diet and increased consumption of processed foods has led to a dramatic reduction in the number of microbes most people consume on a daily basis.
However, dietary data used in the study showed U.S. adults have gradually increased their live microbe consumption over the 18-year study period. This may bode well for the health of the population, researchers said.
This study built on two previously published papers, which conducted the preliminary work necessary for this latest study: "Should There Be a Recommended Daily Intake of Microbes?" and “A Classification System for Defining and Estimating Dietary Intake of Live Microbes in US Adults and Children.”
“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,” said 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, noted the research focused not just on probiotics, but on all microbes in foods, including environmental microbes associated with raw fruits and vegetables as well as lactic acid bacteria associated with fermented foods. Thus, the study differs from probiotic research, which focuses 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, said it's possible that future dietary advice could recommend 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 said. “Secondly, these same foods could be providing an additional, hitherto unrecognized, 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.”
Researchers acknowledged that given analyses were of food intakes and not specifically microbe numbers, they could not exclude the possibility that other food components other than live microbes contributed to associated health parameters.
