Vitamin pills: Are they really necessary?

For years, we have always been told that taking a vitamin pill is necessary for insurance — in case we are not able to keep up with a healthy diet. And sure enough, this has pushed up the sale of supplements worldwide — to a staggering $1.7 billion annually in the US alone. Yet, despite the continuous proliferation of vitamin pills, along with an almost motherly advice for us to take them just to be on the safe side, there is actually little science to support the need for a daily intake of vitamins.

In 2006, when a panel of experts formed by the US National Institutes of Health (NIH) reviewed the studies done on multivitamins, they concluded that any evidence of their health benefit was thin, and that the clinical trials were too short to determine any long-term effects. “Essentially, if you don’t take multivitamins, there’s no reason to start,” says Dr. Michael McGinnis, senior scholar and chair of the NIH state-of-the-science panel on the role of multivitamins. “If you do, there’s no evidence to stop.” Adds Dr. Charles Halsted, editor of the American Journal of Clinical Nutrition: “You’re deluding yourself if you think you’re preventing a heart attack or cancer with a multivitamin. It’s a waste of money if you’re perfectly healthy and have a proper diet.”

Those are fighting words for many believers. Indeed, the discussion can turn into a war of dueling studies, with defenders quoting the ones suggesting heart benefits or cancer prevention, and skeptics citing others which showed no beneficial results. “People sort of cherry-pick studies that they like,” says Alice Lichtenstein, professor of nutrition science at Tufts University in Boston. “You can find a study that supports almost anything.”

And, in fact, most nutrition experts continue to say that taking a daily multivitamin pill is a sensible backup plan for the days people don’t get all their fruits and vegetables, whole grain, meat, fish, and legumes. “I think all people — adults, teenagers, and children — should be taking a multivitamin. Period,” says Jeffrey Blumberg, professor of nutrition and director of the Antioxidants Research Laboratory at Tufts University.

Still, many in public health worry that a recommendation for a pill might signal to people that actual food isn’t important. “Does it suggest that, with a vitamin pill, you’ve got an insurance policy, and you don’t need to be concerned about your diet?” asks Lichtenstein. Without convincing evidence to suggest benefit from a daily multivitamin, that’s the wrong message.

Both camps agree, however, that significant problems come not with a basic  multivitamin, which typically covers 100 percent of the recommended intake of the 13 compounds classified as vitamins, but when people start thinking that if a little is good, a lot is better — and ramp up their intake of a vitamin far past the recommended levels.

Mixed Messages

You can’t blame people for being confused. Every week, it seems, some study appears in the literature raising a new vitamin hope or dashing an old one. For example, a July 2005 study of almost 40,000 women found that vitamin E did not prevent heart disease and stroke in most women — though they might provide some protection after age 65. The study also threw cold water on hopes that vitamin E could ward off cancer. On the plus side, a 2005 study reported that vitamin E along with vitamin C, beta carotene, and zinc, helped ward off macular degeneration, one of the leading causes of vision loss in the elderly.

The compound scientists seem most excited about these days is vitamin D, the so-called sunshine vitamin. Once thought of as merely a defense against rickets, it’s now known to improve the absorption of calcium, aiding bone health. But studies also suggest it can lower the risk of colon, breast, pancreatic and ovarian cancer, and more.

There is ample profit in all this vitamin confusion, with entire aisles in health stores and groceries dedicated to specialty vitamins for kids, seniors, men or women who believe, at a minimum, that the pills can’t hurt and might help. Certainly, specific formulations can be useful. Children need lower amounts of nutrients, for example, and women, after menopause, need less iron than younger women. But other bottles hint at more: breast health, memory enhancement, energy boosts, or increased manliness. Such claims are so thin in science that every word on the packaging is carefully calculated to be a non-promise. “If it sounds too good to be true, it is,” Blumberg warns.

Problems come with popping megadoses of individual vitamins. The recommendation for vitamin B6, for example, is 1.3 mg for adults, slightly higher for people over 50. It’s often sold in tablets containing many times that amount. “We get concerned when people overdo it,” says Chris Rosenbloom, professor of nutrition in the College of Health and Human Sciences at Georgia State University. A few years ago, she says, there was a trend among women to take huge doses of vitamin B6 in the hope of reducing symptoms of premenstrual syndrome. (Currently, in the Philippines, many people are taking high doses of vitamin B6 for weight control on the belief that it reduces appetite.) “People were taking hundreds, even thousands of times the recommended dose … they were having numbness in their legs, tingling in their fingers.” Some years later, an Institute of Medicine committee looking at the safe, upper limits of vitamins found that above 100 mg, B6 can indeed cause such numbness.

That is not the only case the panel reported of megadoses causing harm. Too much niacin, more than 35 mg a day, can cause flushing and itching. People with a deficiency in vitamin B12 — and that includes a lot of elderly people — are at risk of crippling neurological damage if they take too much folic acid, because the substance masks their B12 deficiency, leaving it to languish untreated. The committee set an upper limit of 1,000 mcg of folic acid a day. (The recommended dose is 400 mcg, more for pregnant and lactating women.) People can also get into trouble overdosing on vitamin A, E, D, niacin, zinc, and selenium, the panel members found.

Vitamin Plus

Megadosing is one thing. A humble multivitamin is another. Those who favor its use point to studies such as the one published in 2003 that found people, aged 45 to 65 who took a daily multivitamin and mineral supplement, had fewer colds and other infections than those given placebo. The improvement was largely seen among people in the study who had diabetes. Over the course of a year, only 17 percent of people with diabetes who took vitamin pills reported an infectious disease, compared with 93 percent of those who took a placebo.

The study clearly suggests that those with an underlying disease, diabetes, interfering with their nutritional intake, stand to experience a significant improvement. For them, a vitamin pill is a good backup. But the study offers no evidence that people already getting ample nutrients in their diet will fare better with a pill.

There were some clear messages from the 2006 NIH study, McGinnis says. Examining all evidence available through clinical trials, the panel found three well-established benefits from specific vitamins: Folic acid protects against neural tube disorders in developing fetus; calcium combined with vitamin D helps prevent bone fractures; and vitamin C, E and zinc in combination reduced eyesight deterioration from age-related macular degeneration.

Even those most dismissive of daily vitamins are quick to concede that specific groups of people, including those with underlying problems such as diabetes, have nutritional needs not typically met through diet. Almost everybody older than 65 needs a vitamin B12 supplement, for example. People dieting to lose weight and eating fewer than 1,500 calories should also take a multivitamin, as should pregnant women and women of childbearing age.

Yet, many nutrition experts believe that the real issue is different — that people need to simply eat better. “We need to focus on quality of our diets,” says McGinnis. That seems to be the more important consideration. After all, the best way to take these vitamins and minerals is not in the form of a pill but in its natural state in the food we eat!

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Don’t miss next week’s column, which will discuss the current recommendations on the right amount of vitamins and minerals you should take.