Nutrition News: Exercise and Your Gut
We've all heard plenty about our gut microbiome and how important it is to good health. What you may not have heard is that exercise may be as important as any probiotic to build a good gut microbiome.
Just what is our microbiome? Our gut microbiota starts with birth and affects functions throughout the body. Literally trillions of bacteria live in our digestive tract and play an important role in our health. Of the thousands of species of gut microbes that live inside us, some are healthy -- and some are not.
The good gut bacteria break down food, manufacture vitamins and train our immune system. When we have more good bacteria than bad, our health improves. In the same way, imbalances in gut bacteria have been linked to obesity, mood disorders and altered immune response.
We know a balanced, healthy diet that includes high-fiber and fermented foods (sauerkraut, miso, kefir, kimchi, kombucha, yogurt) can help our gut bacteria thrive. Foods high in fiber -- like raspberries, artichokes, green peas, broccoli, chickpeas, lentils, beans, whole grains, bananas and apples -- help good gut bacteria grow. Other helpful foods include chicory root, leeks, onions, garlic, asparagus, whole wheat, spinach, oats and soybeans.
Two studies at the University of Illinois found evidence that exercise can change the composition of microbes in the gut. In the first study, scientists at the U of I and Mayo Clinic transplanted fecal material from exercised and sedentary mice into the colons of sedentary germ-free mice, which had been raised in a sterile facility and had no microbiota of their own. They found recipients of the exercised mouse microbiota had a higher proportion of microbes that produce butyrate, a short-chain fatty acid that promotes healthy intestinal cells, reduces inflammation and generates energy.
In the second study, the team tracked changes in the composition of gut microbiota in human participants as they transitioned from a sedentary lifestyle to a more active one -- and back again. Researchers recruited 18 lean and 14 obese sedentary adults, sampled their gut microbiomes, and started them on an exercise program during which they performed supervised cardiovascular exercise for 30-60 minutes three times a week for six weeks. Researchers sampled participants' gut microbiomes at the end of the exercise program and after another six weeks of sedentary behavior.
Fecal concentrations of SCFAs, in particular, butyrate, went up in the human gut as a result of exercise. These levels declined again after the participants reverted to a sedentary lifestyle.
The bottom line? Here's another reason to add daily exercise to your routine -- along with healthy eating habits and plenty of fiber. Your gut will be glad you did.
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