The Medicine Cabinet: Ask the Harvard Experts
Q: I need advice to reduce intestinal gas. Not only is it embarrassing, I also experience a lot of discomfort unless I let it out. Suggestions, please!
A: A certain amount of flatulence is a normal part of the digestive process. But many people like you have gas and bloating that causes them distress.
Getting to the root of the problem starts with keeping track of what you eat so you can identify potentially troublesome foods and stop eating them temporarily.
Flatulence is produced by bacteria and other microorganisms in the intestines. They feed off various undigested substances in your diet, typically carbohydrates.
Some foods, like beans, are well known to cause gas. They contain a number of indigestible carbohydrates that bacteria in the gut enjoy feasting on.
You might not realize you have lactose intolerance. But it’s always worth considering. Lactose intolerance means the body doesn’t make enough of the enzyme, lactase, needed to digest lactose, a carbohydrate. The lactose passes undigested through the intestine, where the resident bacteria feed on it.
Vegetables are rich in healthy carbohydrates, but some can trigger gas or bloating. Problem vegetables for many people include broccoli, cabbage, onions, Brussels sprouts, and potatoes.
Artificial sugars are a common cause of gas that is often overlooked. Certain plant-derived substitutes for natural sugar, particularly those whose names end in “tol,” also cause gas. These include sorbitol, mannitol, lactitol, and xylitol. They are found in a wide range of processed foods, including sugar-free chewing gum and candies and “low-carb” products.
Some people are intolerant to fructose, a natural sugar found in fruit. Common gas producers include apple or prune juice and dried fruits. Fructose is also found in many processed foods, fruits and sugar-sweetened beverages.
Here’s a plan. Read ingredient lists carefully when shopping to look for hidden troublemakers. Keep a food diary and note what foods seemed to lead to gas. Stop eating suspect foods one by one and then add them back to see how you tolerate them.
Of the commercial products that might help, enzyme formulations (tablets and liquids) that can serve as lactase replacements are very helpful for people with lactose intolerance. Other products, such as peppermint tea or oil and activated charcoal, have mixed evidence regarding their efficacy to reduce gas. Note that charcoal can interfere with absorption of some medications.
(Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, please visit www.health.harvard.edu.)
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Erin O’Donnell is a freelance health and science writer, parent, and graduate of Northwestern’s Medill School of Journalism. Walks by Lake Michigan make her happy.