The Vitamin Myth

While some vitamin supplements can boost your health, others may actually harm.

By Neena Samuel from Reader's Digest | November 2007
Vitamin MythPHOTOGRAPHED BY NICHOLAS EVELEIGHThose who take certain antioxidants have a 16% higher risk of mortality than those who don’t.

Google “vitamins” and you get 50 million results and the wildest claims you can imagine. That’s almost six times more than what you get for “Brad Pitt,” but the descriptions are just as breathless. As you navigate the maze of sites, you see phrases claiming vitamin supplements can “increase energy,” “stimulate brain function” and “improve sex drive.” There are promises of “reversing cancer” and “removing plaque” from your arteries. It all helps explain why Americans shell out $7.5 billion a year on vitamins, hoping to prolong life, slow aging and protect against a bevy of illnesses.

But new research not only refutes many of these claims, it also shows that some of these vitamins may in fact be harmful.

  • A February report in the Journal of the American Medical Association found that taking antioxidant vitamins actually increased a person’s risk of dying by up to 16 percent.
  • A study by researchers at the University of Washington last May found that high doses of vitamin E taken over ten years slightly elevated lung cancer risk in smokers.
  • Researchers at the National Cancer Institute found that men who took more than one multivitamin daily had a higher risk of prostate cancer.

Antioxidant Paradox
The antioxidant study, in particular, surprised a lot of people and has prompted a heated debate. Antioxidants such as vitamins A, beta carotene (another form of vitamin A), E and C have long enjoyed a reputation as disease fighters because they’re thought to protect against free radicals that can damage cells and speed up aging. But in 47 randomized trials involving almost 181,000 adults, researchers found that taking vitamins A, beta carotene and E, alone or in combination, actually increased a person’s risk of dying by up to 16 percent.These latest findings made headlines, but they haven’t convinced everyone. A number of leading health experts criticized the JAMA review, including Jeffrey Blumberg, PhD, head of the Antioxidants Research Laboratory at the USDA Human Nutrition Research Center on Aging at Tufts University. He argued that the results were skewed because the studies it reviewed were too diverse and could not be easily compared. It also included deaths from all causes, not just health-related ones.

Based on these flaws, Bernadine Healy, MD, former head of the NIH and the American Red Cross, deemed the study alarmist and silly. Still, others wonder, why take the risk if you can get what you need from the produce aisle or the farmers’ market?

“Unless your doctor says you need supplements for a specific diagnosis, there is no reason to take them and no need to spend the money,” says the review’s senior author, Christian Gluud, MD, of Copenhagen University Hospital in Denmark.

The prostate cancer findings from the National Cancer Institute were even more startling because the culprit was the innocuous multivitamin. Researchers found that men taking multivitamins more than once a day increased their risk of advanced prostate cancer by 32 percent and nearly doubled their risk of fatal cancer, compared with men who didn’t take multivitamins. The risk was highest in those who had a family history and also took selenium, beta carotene or zinc supplements.

Don’t throw away those bottles yet, though. Many experts agree that taking a daily multivitamin is a smart move, especially for those of us who don’t regularly eat whole grains, fresh veggies and fruit. Still, you may want to think twice about swallowing handfuls of certain supplements.

C Is for Colds
Even if a vitamin does no harm, it may do, well, nothing. Take the ever popular myth that popping vitamin C will stave off colds. A review of 30 studies involving more than 11,000 people who took at least 200 mg of vitamin C daily found that it offered little protection in reducing the length or severity of common colds for most people. It did work for some people, such as marathon runners and skiers, who undergo periods of high stress, but the study’s authors say the rest of us shouldn’t bother taking it.

Dosage Dangers
Most people think of vitamins as natural and safe since they’re sold over the counter everywhere, including health food stores. And many consumers figure you can’t get too much of a good thing. But you can, particularly if you’re on prescription drugs.

Megadoses of E, for example, can increase the risk of bleeding if you’re already on heart meds like blood thinners. An earlier 2004 analysis by Johns Hopkins researchers found consuming 400 IU or more of vitamin E a day alone (some products on the market today contain 1,000 IU per capsule) was associated with a higher risk of dying and should be avoided. (One theory says high doses may alter your natural immune function and actually become pro-oxidant.) Taking too much niacin without a doctor’s okay can lead to liver damage and other problems over time. And too much vitamin A increases the risk of liver and lung cancers, and can cause birth defects and reduce bone density.

What consumers tend to forget is that many processed foods and so-called diet foods, from crackers to energy bars, are “fortified” with additional vitamins and minerals. Even some bottled waters, juices and sodas have added them in an effort to appear more healthy. Eat and drink enough of these products, take a few pills, and you could be overdosing. Though rare, bad side effects and even deaths do happen from a vitamin overdose, reports show.

“Taking more than a DRI [dietary reference intake] of vitamins is associated with problems,” says Michael Roizen, MD, Cleveland Clinic’s chief wellness officer and coauthor with Mehmet Oz, MD, of the You series of health books. “These include osteoporosis, which is caused by too much vitamin A, and neurological problems such as headaches, wobbliness and confusion, caused by too much folate without enough B6 or B12, or too much B12 without enough B6 or folate”