Fart Facts

Remember Bob Wojcik? That sinister soliciter of subterfuge? That harrowing harbinger of happenstance? Yeah him. He's the one that put my marathon training on ice with his calf stretching advice.

Well he's trying to get back into my good graces by giving me this really interesting documentation from the Mayo Clinic on farts and farting.

Just when you think he can't do anything worse, he sends me this stuff.... and totally redeems himself.

What is intestinal gas?

More than 99 percent of intestinal gas is a mixture of the same odorless gases that are present throughout the environment. These include nitrogen, oxygen, carbon dioxide, hydrogen and sometimes methane. But the exact composition of this mixture varies from person to person, depending on body chemistry and diet.

The nitrogen, oxygen and most of the carbon dioxide in intestinal gas come from the air you swallow when you eat, drink, chew gum or smoke. Chemical reactions in your stomach also produce some of the carbon dioxide content of gas.

Bacteria normally present in the large intestine produce the hydrogen and methane in gas. These bacteria feed on undigested food and release gases during a process called fermentation.

Which foods cause intestinal gas?

Carbonated beverages may cause gas. So can carbohydrates because they often contain indigestible sugars, starches and fiber. For example:

• Lactose. Milk and milk products such as cheese and ice cream, as well as some processed breads, cereals and salad dressings, contain the sugar lactose. While most people can digest lactose with no difficulty, some have trouble because they don't produce any or enough of the enzyme lactase, which splits lactose into digestible parts. Without lactase, milk and other lactose-rich foods ferment in the intestine, releasing excessive gas. People of African, Asian and American Indian descent are most likely to be deficient in lactase.
• Fructose. Onions, artichokes, pears, wheat, and some soft drinks and processed foods contain this sugar, which may be difficult to digest.
• Sorbitol. Apples, pears, peaches, prunes, and some sugar-free foods, candies and chewing gum contain the sugar alcohol sorbitol, another compound that's hard to digest.
• Raffinose. This sugar is found in beans, cabbage, brussels sprouts, broccoli, asparagus and whole grains.

Rice is the only starch absorbed almost completely by the small intestine. Because rice starch never reaches the large intestine, gas-producing bacteria don't break this starch down. But other starches, including potatoes, corn, noodles and wheat, are gas producers. Dietary fiber, found in beans and wheat bran, also tends to produce gas. When research subjects ate a diet in which half of their calories came from pork and beans, they experienced a tenfold increase in their normal gas production.