Mythbusting Misconceptions About the
MICROBIOME
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by Kara Credle and Nancy Morrow
rom yogurt lids to age-old proclamations, myths and misconceptions about the role of the microbiome in human health may cause confusion about how this important aspect of health works and impacts everyday health.
Microorganisms living in the human body outnumber human cells by 10 to one. This estimate came from microbiologist Thomas Luckey in 1972, but recent research suggests that the ratio is closer to one-to-one. Scientists found that Luckey underestimated the average amount of human cells, miscalculated the number of bacteria in the human body and incorrectly assumed that the microbiome was spread evenly throughout the gastrointestinal (GI) tract from the mouth to the colon. The reality is that a large majority of bacteria constituting the microbiome congregate in the lower GI tract. A one-to-one ratio of bacterial cells to human cells is still incredible, as bacteria in the microbiome grow right alongside human cells through all stages of life.
This is exactly what a healthy microbiome looks like. There is no standard for a healthy microbiome. The science is still growing, and although researchers learn something new about how the microbiome works all the time, there is still a lot that is unknown. What we do know is that certain lifestyle factors like diet, physical activity and environmental exposures affect the composition of the microbiome, and certain bacterial species are associated with positive and negative health effects. But the composition of our microbiome can look vastly different than that of our neighbor’s, although both may be considered healthy. For most people, supporting the microbiome is less about finding the right ingredients at the right store in the right season for the right recipe and more about, “a pinch of this and a pinch of that", based on a general understanding of what promotes microbial populations to flourish and diversify: lots of fruits and vegetables, regular physical activity and other healthy lifestyle habits.
Illustration credit: Standard Process.
Prebiotics and probiotics are both live cultures of bacteria. One of these is not like the other. Prebiotics are different from probiotics in that they are not made up of live bacteria. While the term “biotic” typically references something that is a living organism, prebiotics are substances like fiber or human milk oligosaccharides (HMO) found in breast milk that feed bacteria in the microbiome. Probiotics are live microorganisms often found as ingredients in nutritional supplements supporting the microbiome, as well as in a variety of foods like yogurt, kombucha and other fermented products. Prebiotics are like the fertilizer that feeds beneficial bacteria in the microbiome, and probiotics are like caretakers that crowd out the weeds attempting to take over the garden.
A healthy microbiome only promotes digestive health. Gut bacteria play a role that extends beyond the digestive tract, influencing nearly every aspect of the body’s everyday functions. We’ve known for a long time that they play a role in protecting us from pathogens, producing certain vitamins and providing fuel for intestinal cells, but studies also show their importance for regulating pain and inflammation. The microbiome is an important part of human health, as it influences physiology in multiple systems all over the body. Scientists continue to study the microbiome and how specific components can affect change in human physiology, further determining how human lifestyle choices like diet, physical activity and environmental exposure are linked to changes in the microbiome and overall health status. Kara Credle is the clinical nutrition communication specialist at Standard Process, Inc., managing the digital education platform WholisticMatters.com. Nancy Morrow is a Washington state certified nutritionist with a master’s degree in human nutrition. She is the technical nutrition coordinator at Standard Process, Inc., and serves as an adjunct professor of nutrition science at Purdue University Global. September 2020
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