Got the zumes?

Men's Fitness, Nov, 2003

Every time I take vitamin C, I have digestive problems. Could I be allergic to it?--T.E., SEATTLE, WA

THE SIDE EFFECTS of taking vitamin C, also known as ascorbic acid, can be downright unpleasant for some people. "Digestive problems, namely diarrhea or upset stomach, are the usual symptoms," says Melinda Safir, a staff nutritionist at the Cooper Clinic in Dallas, Texas. But it's questionable whether the discomfort is caused by allergies, she adds. "Often, vitamin C is derived from corn. People who are sensitive to corn should look to alternative sources, such as sago palm." Since vitamin C is generally nontoxic, digestive problems are often related to excessive intake. Safir recommends taking the following steps:

AVOID HIGH DOSES OF VITAMIN C. The normal range for an active guy is 500 to 1,000 milligrams a day, which is best taken in several doses throughout the day. "Taking more than 2,000 milligrams daily can result in diarrhea, gas, or stomach upset," Safir notes.

TAKE VITAMIN C WITH MEALS RATHER THAN ON AN EMPTY STOMACH. Safir says this strategy will have a buffering effect and help you avoid intolerable problems with digestion.

TRY DIFFERENT FORMS OF VITAMIN C SUPPLEMENTS. "Tablets, capsules, and chewables are the most popular forms, but vitamin C also comes in powdered crystalline, effervescent, and liquid forms," says Safir. "A buffered ascorbic acid is available for those who are prone to heartburn or have a sensitive stomach. Individuals plagued by stomach ulcers can better tolerate the buffered form of the vitamin."