When Good Foods Are Bad for You

Grapefruit

Even good foods can cause havoc in your life. Here are a few to keep your eye on.

Food

Grapefruit

Problem

Prescription drug interaction and potential kidney failure

What Happens

While grapefruit is an excellent source of vitamin C and contains fiber, potassium, and lycopene for cancer prevention, it could be off-limits for those on some prescription medications. "It can alter the effects of the drug, causing serious side effects. The biggest concerns are with cholesterol-lowering medications. The grapefruit may prevent the liver from breaking down the drug, causing toxic levels to build up that could cause kidney failure," says Lona Sandon, MEd, RD, a professor of nutrition at the University of Texas Southwestern Medical Center at Dallas.

How Much Do You Have to Eat?

"One glass of grapefruit juice or one grapefruit is enough to interfere with medications. I am not sure at what level kidney failure might occur, but it's probably not a good idea to push it. It likely depends on a person's body weight. No level of grapefruit intake is considered acceptable with these medications," says Sandon.