Spill your Guts

The colon is the final route taken by digested food in your gastrointestinal (GI) tract. Your large intestine performs several functions, including the absorption of electrolytes (sodium and potassium) and the excretion of solid waste; it is also home to various microorganisms, both good and bad, that aid the digestion of fiber and the synthesis of important vitamins.

More specifically, your large intestine houses more than 400 different species of bacteria, consisting of over 100 trillion microbial cells (this is more than 10 times the number of cells in your body)! While some of this intestinal flora is pathogenic, a good deal of it is beneficial to your gastrointestinal health. The "good" bacteria keeps the "bad" in check, assists in the digestion of lactose (naturally-occurring milk sugar), helps create vitamins K (important for blood coagulation) and B (biotin, needed for healthy metabolism and strong nails and hair), and ferments insoluble fiber and starch into energy used by the bowel itself.

Buzzwords concerning good gut bacteria include "probiotics," which are microorganisms found in fermented foods such as yogurt, miso (fermented soybean paste), and acidophilus milks, and "prebiotics," which are indigestible carbohydrates (such as inulin, found in wheat, onions, garlic, asparagus, and bananas) that promote good gut bacteria growth. It is believed that consuming a diet that includes pro- and prebiotics can help prevent and alleviate the symptoms of several colonic diseases.

Of course, all this work creates a less desirable by-product: about 1 to 4 pints of daily gas, also known as flatulence. This gas is a mixture of swallowed air and gases emitted during the bacterial fermentation of carbohydrates in the colon.

Media (text reference: Wardlaw's Perspectives in Nutrition, 8th edition)
created and published by Rebekah Carter (2010).
Colon radiograph from the University of Washington (2000).