Although you might like to think of yourself as your own person, you actually share your body with many millions of bacteria.
In fact, it's estimated that the human gut contains 100 trillion bacteria, or 10 times as many bacteria as cells in the human body.
These bacteria, or gut flora, influence health in many ways, from helping to extract energy from food to building the body's immune system, to protecting against infection with harmful, disease-causing bacteria.
Researchers are only just beginning to understand how differences in the composition of gut bacteria may influence human health. From what we know so far, here are five ways gut flora affect wellness:
A growing body of research suggests that gut bacteria influence weight. One recent study found that obese people have a less diversity in their gut flora than lean people. Other studies have suggested that an increase in a group of gut bacteria called Firmicutes, and a decrease in a group of gut bacteria called Bacteroidetes, are linked with obesity.
Research done on animals may provide clues about how gut bacteria affect weight gain. One recent study found that mice that received a "gut bacteria transplant" from an obese person gained more weight and fat mass than those who received bacteria from a lean person.
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