Evidence is thin that multivitamins are beneficial, but they seem benign
Earlier this month, I found myself standing in front of a massive display of multivitamins at a local grocery store, confounded by the options: There were supplements for children, teens, males, females, pregnant women, adults "50 and wiser," those in peri-menopause and menopause, and seniors; for immune support, high energy and stress relief; pills to be taken once, twice or three times a day and supplements to be taken in liquid form; with added ingredients such as antioxidants, iron or lycopene; and whole-food options derived from actual produce that promise more bang than their synthetic counterparts, albeit for much more of my buck.
So many choices, so little evidence that any of these products actually result in better health. Indeed, although the vitamin, mineral and supplement industry is a booming $25 billion business and more than half of Americans take a daily multivitamin, the evidence on effectiveness is decidedly mixed.
In fact, while some older studies have linked multivitamin use to the prevention of conditions such as breast and colon cancer and heart disease, the latest research has shown absolutely no impact on health and disease prevention, over time. Most recently, a rigorous, widely regarded study published last February in the Archives of Internal Medicine tracked more than 161,000 post-menopausal women over eight years and found that multivitamins had no effect whatsoever in 10 health-related categories, from the rate of the most common cancers, heart attack and stroke to overall mortality.
"The big takeaway message is that if someone takes a multivitamin, it doesn't make them any healthier, but it doesn't really harm them, either," says lead author Marian Neuhouser, a cancer prevention researcher at the Fred Hutchinson Cancer Research Center in Seattle. "So then consumers have to ask themselves: What is really the benefit of spending money on these products, if they are not going to decrease the risk of common diseases that affect women or benefit health? It's a waste."
These findings echo an official 2006 statement by a National Institutes of Health panel on the safety and effectiveness of single, paired and combination supplements, which "indicated no evidence to suggest that people taking multivitamins should stop and also found that if people are not taking them, then there's absolutely no reason they should start," says Paul Coates, director of the NIH's Office of Dietary Supplements. He notes that specific vitamins and minerals were recommended for a select few groups, including calcium and Vitamin D for bone health in post-menopausal women and folic acid for women of childbearing age, to prevent birth defects. Supplements can also be helpful in the case of a diagnosed deficiency. But he said that more research is necessary to make a concrete recommendation about multivitamins and multi-minerals for chronic disease prevention.
However, Coates points out that the lack of rigorous science on this topic is an ongoing problem: "It's a challenge to construct appropriately powered clinical studies to examine the potential health effects of nutrients, over and above what people are getting in their diets. . . . There's no zero exposure, no real placebo." Neuhouser said that multivitamin users tend to have healthier lifestyles, which can make it difficult to distinguish whether health benefits come from that one-a-day or from eating a more balanced diet and exercising regularly.
One of the main issues with multivitamins, say experts, is that they typically aren't necessary here, given the ready availability of fruit, vegetables and whole grains and the advent of bread and cereals fortified with folic acid, milk packed with Vitamin D and the like. "Most people in the U.S., I posit, are not deficient in too many, if any, of these important nutrients we get from food," Coates says. "It's definitely open to lot of argument, and there are people who would beat me into the ground for taking that position -- and one can certainly point to people in need, no question. But generally speaking, multivitamin and multi-mineral users, especially, tend to be people who engage in other healthful behaviors and may not need the additional support."
A study published in the Archives of Pediatrics and Adolescent Medicine last year looked at data on more than 10,000 children between ages 2 and 17 and found that while roughly one-third had used vitamins within the previous month, the majority did not need to supplement their diet. As a result, some scientists worry about the over-consumption of certain nutrients and the potential for adverse effects. (For instance, high doses of Vitamin E have been linked to increased risk of death.)
But just because supplements may not lead to better health, that doesn't mean we don't need the vitamins and minerals they contain. It's just that popping a pill -- however appealing a notion -- is simply not as effective or as efficient a way to get those good things as eating a balanced diet containing plenty of fruit, vegetables and whole grains.
"Food is the absolute best way to get all your vitamins and minerals, because you're not just getting vitamins, but other important nutrients and hundreds of bioactive compounds, and also the media in which the vitamin is carried," says Myrtle McCulloch, a clinical assistant professor of nutrition at the Georgetown University School of Nursing and Health Studies. For instance, she points out that Vitamin D and calcium are best absorbed in an alkaline medium such as milk. "When you pull out just a few nutrients from fruits and vegetables, you're kind of missing the boat and not getting the full complement of all the compounds in healthy foods and the complex ways they work together," adds Neuhouser.
Still, McCulloch believes that a simple multivitamin with 100 percent of the recommended daily allowance can provide some measure of insurance for those who don't always eat the way they should. But she warns consumers not to believe the hype that surrounds supplement advertising and marketing, and says there's no proof that there's any health difference between the standard generic vitamin you pick up at the drugstore and a brand-name version or an even pricier whole-food-based option.
"Your body doesn't know whether you're using a chemically formed vitamin they make in lab or whether it's extracted from an orange, once it's in pill form. Your body and tissues don't know one brand from another and don't know whether you paid $4 or $40," says McCulloch. Since the Food and Drug Administration doesn't regulate vitamins and other supplements as drugs, manufacturers don't have to prove their effectiveness, she says, which makes an independent stamp of approval from the nonprofit U.S. Pharmacopeia essential to guarantee a certain level of quality. "But really, the best thing to do is just concentrate on eating more-balanced meals."
So, although multivitamins have long been recommended by my doctors and other health practitioners, and I've taken a range of them over the last several decades -- everything from Flintstones to prenatals to outrageously expensive whole-food supplements suggested by an acupuncturist -- I am now forced to admit that there's no easy fix here.
As much as I want my quick-and-dirty daily pills to guarantee good nutrition -- and to compensate for the fact that I have been eating far too many chicken nuggets and far too few fruits and vegetables these days -- the next time I'm at the grocery store, I think I'm going to skip the looming supplement display and focus instead on the produce.