Megagood or megawaste?

Vitamins: Taking huge doses of supplements, experts warn, may be a waste of money -- or worse.

May 09, 1999|By NANCY MENEFEE JACKSON | NANCY MENEFEE JACKSON,SPECIAL TO THE SUN

Swallowing those much-touted megadoses of vitamins isn't quite the same as throwing money down the drain. It's more like flushing money down the toilet, because most of what you've spent your money on will be eliminated by your body, which is better at recognizing excess than you are.

And in some cases, too much of certain vitamins or minerals actually can be harmful.

This reality notwithstanding, the popularity of vitamins and megavitamins has soared, hitting a record $5.7 billion in sales in 1997, compared with $3 billion in 1990. Supermarket and drugstore aisles are lined with an astounding and confusing array of vitamin choices. Those who want optimum health -- and who doesn't -- worry whether they're getting enough beta carotene, whether vitamin C will prevent cancer, whether a lack of vitamin E might be affecting their love life.

"You almost need a Ph.D. to go in the vitamin aisle these days," says Vicki Lucas, Ph.D., vice president of women's services for MedStar Health, which includes five Baltimore-area hospitals.

The simple truth is that for most people, a general multivitamin supplement -- and for women, a supplement with iron -- will give you what you need. And yes, Lucas adds, the store brand is fine, too.

Dr. C. Wayne Callaway, associate clinical professor of medicine at George Washington University and an expert in endocrinology and vitamins, worries that vulnerable people get taken in by false ideas about vitamins. "I've seen guys with AIDS spending $200 a month on vitamins," he says.

Or consider the person taking vitamin E to help lower elevated LDL, the bad cholesterol. Since the LDL is a transporter for vitamin E, the LDL with vitamin E on it is less likely to be oxidized, a process that contributes to heart disease. So vitamin E works as an antioxidant. That seems simple enough. But if the person taking it has elevated triglycerides, says Callaway, "You can give them a bucket of vitamin E and it won't help."

For years, Callaway served on government committees that examined the recommended daily allowances and participated in clinical trials to examine the efficacy of vitamins.

A little history is in order. Callaway explains that the recommended daily intakes were a response to the needs of the country to feed military and civilian personnel during and after World War II. The original criteria were developed to prevent deficiencies in the men who would be protecting democracy. A margin of safety was built in, and the idea of recommended daily allowance, or RDA, was born.

The National Academy of Science's Food and Nutrition Board is studying the RDAs to update them to reflect the latest research.

With the exception of caloric intake, Callaway points out, "the RDAs were meant for over time. One can be below the RDAs [temporarily] and not be deficient. Ninety-nine percent of us do not meet the RDAs on any given day, unless we take a supplement."

And remember, a supplement is in addition to food, and a balanced diet with plenty of fruits and vegetables provides the necessary vitamins and minerals. To try to use vitamins to achieve some idea of optimal health can pose problems.

"There's this thought that if a thousand milligrams is good, then 5,000 must be better, and that's not the case," Lucas says. She points out that since the RDAs were developed with men in mind, even the recommended dose can be more than women need.

The idea that vitamins could prevent or attack disease took root in the 1960s, when vitamin C was touted for the common cold, a theory that's still controversial 30 years later. And now, says Callaway, vitamin C is thought to be effective against cancer and heart disease, even though controlled studies have not documented that.

Here's another problem with megadoses of vitamin C, Lucas says: The recommended dose is 60 milligrams. The body simply cannot absorb more than 200 milligrams, and what the body can't absorb just, as Lucas tactfully puts it, "enriches the water supply."

But not all supplements are eliminated so easily. Selenium is thought to protect against stomach cancer, but if too much is taken, fingernails will soften and fall off and hair will fall out.

"Where the danger is is when one takes an excess of a single nutrient," says Callaway. If someone takes 50 milligrams or more of zinc, the lining of the intestine will make a protein that binds the extra zinc. But it also will bind copper, resulting in a copper deficiency.

Beta carotene or Vitamin A, another touted supplement, might actually increase lung cancer in smokers. Lycopene -- found in tomatoes, red beans and peppers and thought to prevent prostate cancer -- might compete with other molecules, such as beta carotene, if too much is taken. Magnesium is harmful at high levels, and even Vitamin C, at high levels, can contribute to the development of kidney stones.

"The nice thing about foods is that you eat a variety of them, they balance out, and you're not likely to get toxicity," says Callaway.

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