The microbiome in our gut consists of up to 1000 different types of bacteria and about 100 trillion cells. As such, it has ten times as many cells as we have. The development of the microbiome depends on a number of factors: absorbtion of microorganisms from the mother’s vagina at birth, breast feeding by the mother, what foods a person eats, antibiotic use, stress and genetic factors.
A Belgian study, recently published in Science, is one of the first population-wide studies on the variation of gut bacteria and its links to health, diet and lifestyle. The Flemish Gut Flora Project analyzed human stool samples from 5000 volunteers over 4 years. Factors such as transit time, health, diet, medication, gender and age were identified as linked to gut flora composition. Fiber intake was related to a healthy variety of microbes in the gut. While breastfeeding promotes the growth of beneficial bacteria in the gut, whether or not a person was breast fed as a child did not relate to adult gut microbe variety. This indicates that there is an opportunity in later life to change gut microbe composition with the right diet. The researchers said that their findings may relate to new ways of influencing mental health because of the close connection between the gut and the brain.
According to a recent study from The Mount Sinai School of Medicine, specific combinations of gut bacteria from mice with ‘social withdrawal’ produce substances that can make normal mice show similar behavior. Social withdrawal is the mouse equivalent of depression. Also, similar gut bacteria influence the myelin content of brain cells, potentially affecting demyelinating diseases such as multiple sclerosis. Research in this area has shown that children with multiple sclerosis have been found have an increase in gut bacteria linked to inflammation. Myelin is a sheath-like material that forms a protective coating around nerve fibers.
Since the gut microbiome can influence the central nervous system and the immune system, it’s important for all of us to feed it well. We know those microbes like plant food with fiber, so go high on 100% whole grains, fresh and dried beans of all kinds, vegetables and fruits. If you do this, there is little room left for refined flour and sugars. Here’s the good news – there are bacteria in our gut that turn dark chocolate into compounds that have health benefits. Dark chocolate helps restore flexibility to arteries, while also preventing white blood cells from sticking to the walls of blood vessels. Try getting unsweetened cocoa powder and carefully adding your own sweetener. I prefer xylitol - it’s actually good for the teeth!
Sadja Greenwood, MD, MPH Back issues on this blog
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