Vitamin Pills: Popping Too Many?

Vitamin D

"This can be tricky because we need some, and as we get older we need more," Rosenbloom tells WebMD. "But the risk is that we get too much, which can actually cause calcium to leach out of your bones." Vitamin D is found in some calcium supplements; some orange juice products are fortified with vitamin D. If you're somebody who can't drink dairy, getting vitamin-fortified orange juice makes sense. "But if you do drink dairy, and then you take a supplement, it's that layering that I get concerned about," she says.

Vitamin B-6

This is a water-soluble vitamin, which means you just pee out the excess, says Rosenbloom. The upper tolerable limit is 100 mg day, and in pill form it's easy to get that much. "In high doses, people have problems with temporary nerve damage -- they lose feeling in their hands and feet," she tells WebMD.

Fifteen years ago, women were told to take megadoses to help with depression and PMS, but that's been debunked, she says.

Vitamin E

People focus on E to prevent Alzheimer's, heart disease, macular degeneration, cancer, "the list goes on," says Blumberg. The upper tolerable level is 1,000 milligrams (1,500 IU); the RDA is 30 IU. "There is no way to get an overdose from diet or fortified foods. In an Alzheimer's study, people took 2,000 IU for four years and didn't have any adverse effects. In another study, people took 800 IU for six years, with no adverse effects, he says.

Read the Label

Pay attention to food labels, says Rosenbloom. "When you're grocery shopping, picking up an energy bar or breakfast cereal, look at the supplement facts panel. If you see 100% of RDA, you may not need a multivitamin supplement."

For a small fee, a nutritionist can evaluate your diet for deficiencies. Also, some online programs provide the same service.

"People are often very surprised when they see the nutrients they are getting and what they're not," says Rosenbloom. "Maybe they need a calcium supplement, maybe your vitamin C is low if you don't eat any citrus."

Won't Prevent the Inevitable

Blumberg's prudent advice: "Take a multivitamin. Take a calcium supplement, if you don't drink much milk. If you're taking medicine that interferes with nutrient absorption, if you're an older person whose calorie intake is low, if you're an athlete, if you're pregnant -- all of those are good reasons to take a multivitamin supplement."

Just stay away from those whopper-sized, 25,000 milligrams, vitamin A pills, he says.

"By and large, nutrient supplements -- vitamins, minerals -- are enormously safe," Blumberg says. "Even if you drink a gallon of OJ a day, eat fruits and vegetables, then take 1,000 milligrams of vitamin C, you're not going to even get close to toxicity."