Most Multivitamin Extras Don't Add Up

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Americans love the notion of getting all their vitamins and minerals by popping a pill. According to the Council for Responsible Nutrition, a supplements trade group, nearly 53% of Americans take a daily multivitamin, at an annual cost of $4.5 billion. Among those who use any dietary supplements, 82% opt for the convenience of a multivitamin.

Last year, however, the largest study of its kind concluded that there was no association between multivitamin use and reduced risk of mortality, any type of cancer or almost any type of cardiovascular disease among postmenopausal women. (Multivitamins with high doses of folic acid and other B vitamins were linked to lower risk of heart attack; see the May 2009 Healthletter.) Lead author Marian L. Neuhouser, PhD, of the Fred Hutchinson Research Center summed up the study's recommendations bluntly: "Get nutrients from food. Whole foods are better than dietary supplements."

For most nutrition scientists, such findings are no surprise. In 2006, a 13-member expert panel convened by the National Institutes of Health (NIH) concluded that there simply wasn't enough scientific evidence to support recommending the use of multivitamins.

Most recently, in a new consumer advisory on dietary supplements issued by the US Food and Drug Administration (FDA), the agency pointedly omitted multivitamins. The FDA did state that "there are many good reasons" to take individual vitamins or minerals in the right dosages, such as: iron and folic acid for pregnant women, B12 for people over 50 (who may not be as able to absorb it from food), and vitamin D for those with darker skin or insufficient exposure to sunlight. The earlier NIH panel likewise cited folic acid in pregnancy and vitamin D, along with calcium, for bone health, plus the antioxidant vitamins shown to help prevent age-related macular degeneration (AMD). Those are the only supplement uses, according to the experts, clearly supported by scientific fact rather than marketing hype.

Not surprisingly, multivitamin manufacturers — especially those targeting the lucrative senior market — have scrambled to make their own health claims and added extra ingredients to boost their appeal. The idea of taking a multivitamin as "insurance" against dietary shortfalls — endorsed by some but far from all nutrition experts — seems pretty plain-vanilla compared to "supporting breast health," "promoting memory and concentration" or "combating free radicals."

So, if you do opt to pop a daily multivitamin, should you also shell out for add-ons that promise to protect everything from your brain to your prostate? Despite the label claims, do multivitamins for seniors actually deliver enough of the nutrients — such as B12, calcium and D — that science says you need? And is there any danger that these souped-up supplements could give you too much of a good thing?

We analyzed the claims and ingredients of more than 20 of the top-selling mulivitamins targeting older adults. In this Special Supplement, we put those "extras" to the test: How good is the science behind their claims?

Vitamins and Minerals The claim: Calcium and vitamin D for bone health.

There's no question that calcium, together with vitamin D, protects bone health and helps prevent osteoporosis. But are the amounts in multivitamins that promise bone benefits adequate without taking specific calcium and vitamin D supplements?

Research led by Heike A. Bischoff-Ferrari, MD, DrPH, of University Hospital Zurich, a visiting scientist at Tufts' HNRCA Bone Metabolism Laboratory, concluded that prevention of hip fractures requires 700-800 milligrams of calcium per day in tandem with at least 800 International Units (IU) of vitamin D. That level of calcium could be covered by dietary sources, according to Dr. Bischoff-Ferrari, but adequate vitamin D can be difficult to obtain from dietary sources alone. Even with 800 IU daily of vitamin D, she adds, only about 50% of seniors reach desired blood levels of the vitamin, and it may take more than that for seniors who start very low in D or who are obese.

Many senior multivitamins — even those touting their bone benefits — fall short of those amounts. Among the best-selling brands, for example, Centrum Silver contains 200 milligrams of calcium, 400 IU of vitamin D. Centrum Silver Ultra Women's comes closer, with 500 milligrams of calcium, 800 IU of D. And One-A-Day Women's 50+ Advantage delivers 405 milligrams of calcium, 800 IU of D.

The claim: Vitamin D "supports breast health."

Although findings from the Women's Health Initiative published in 2008 concluded that there is no evidence vitamin D decreases breast cancer incidence in postmenopausal women, many experts believe the jury is still out. Doses in that study were only 400 IU, for one thing, a level lower than that some believe necessary for cancer prevention. According to the NIH and National Library of Medicine (NLM), "High-dose vitamin D supplementation may be associated with a slightly reduced risk of developing breast cancer. Additional study in this area is warranted." In any case, if your multivitamin — or other sources — delivers the vitamin D needed to protect your bones, you'll enjoy any possible breast-cancer benefits as a bonus.

The claim: Extra antioxidants "promote immune system health."

Vitamins A, C and E plus zinc are frequently touted in multivitamin marketing as boosting your immune system. But the human immune system is complex, and the evidence that any single nutrient or combination of vitamins significantly improves its functioning is mixed at best. Extra vitamin C in particular, though popularly thought to prevent colds, has largely struck out in more than 30 clinical trials totaling over 10,000 participants. Tufts research has found that extra vitamin E enhances immune function in healthy elderly people, and that seniors with low zinc levels were at greater risk of pneumonia. Your best bet for avoiding upper-respiratory infections, however, is to eat a balanced diet, get flu shots and stay away from sick people. (For more on what works and what doesn't to fight colds and flu, see our December 2009 Special Report.)

The claim: Added antioxidants "support eye health."

The NIH report singled out age-related macular degeneration — the leading cause of blindness among older Americans — as one condition where supplements could actually be effective, based on the Age-Related Eye Disease Study (AREDS) by the National Eye Institute. AREDS found that taking high levels of antioxidants and zinc can reduce the risk of developing advanced AMD by about 25%. If you're at high risk for AMD, it's worth considering taking a supplement that provides the amounts used by the AREDS researchers: 500 milligrams of vitamin C; 400 IU of vitamin E; 15 milligrams of beta-carotene (often labeled as equivalent to 25,000 IU of vitamin A); 80 milligrams of zinc as zinc oxide; and 2 milligrams of copper as cupric oxide (which prevents copper deficiency anemia, associated with high levels of zinc intake).

Can you get these extra nutrients in a souped-up multivitamin that claims to "support eye health"? The National Eye Institute answers: "No. The AREDS formulation's levels of antioxidants and zinc are considerably higher than the amounts in any daily multivitamin."

The claim: Extra B vitamins "help convert food into energy."

It's true that B vitamins help unlock the energy in foods, but you're probably already getting plenty of these vitamins in your diet. The added B vitamins in many multivitamins — some, such as SuperNutrition Simply One 50+, contain 20 to 40 times the Daily Values (DV) — mostly just get flushed out of your system. Too much B6 can cause nerve damage, according to the Institute of Medicine, but the danger level is about 50 times the DV.

As the FDA noted, older people sometimes do lose some of the body's natural ability to absorb vitamin B12 from food. According to the NIH/ NLM, "Because 10%-30% of older people do not absorb food-bound vitamin B12 efficiently, those over 50 years of age should meet the RDA by eating foods fortified with B12 or by taking a vitamin B12 supplement. Supplementation of 25-100 micrograms per day has been used to maintain vitamin B12 levels in older people." Senior multivitamins that don't make special claims such as "potent B-energy complex" typically contain 25-80 micrograms of B12, but check the label.

The claim: High levels of B vitamins improve "long-term heart and brain health."

The evidence here is definitely mixed. As noted, extra B vitamins — often also touted as effective against "stress" — were associated with lower heart-attack rates in the recent multivitamin study. A large Norwegian study in 2008, however, failed to find evidence of such a benefit, and was actually halted early because of concerns that a similar trial showed an increased risk of cancer (see the November 2008 Healthletter). It is clear that B vitamins lower blood levels of an amino acid called homocysteine that's associated with heart disease. But whether that in turn reduces cardiovascular events or mortality remains the subject of investigation.

Other researchers are looking into whether lowering homocysteine with B vitamins might benefit the brain and protect cognitive function. But the jury's still out on whether extra B vitamins benefit your brain and prevent cognitive decline.
The claim: Biotin for "radiant skin" and healthy hair.

Biotin is a water-soluble B vitamin that the body can't produce naturally. But biotin deficiency is extremely rare, because daily biotin requirements are relatively small (300 micrograms), it's found in many foods, and the body can recycle much of the biotin it has already used. There's little scientific testing outside of cosmetics makers for claims such as "radiant skin" or "healthy hair," but the NIH/NLM does note that biotin has been suggested as a treatment for brittle fingernails, particularly in women, adding, "There is not sufficient scientific evidence to form a clear conclusion."

The amount of biotin added to multivitamins that boast of its beauty benefits, such as Nature's Bounty Your Life, is typically 100% of the Daily Value.

The claim: Vitamin E "supports heart health."

Not only is there little evidence for this claim, but a widely publicized analysis of data from 19 previous clinical trials actually found an increased risk of mortality from extra vitamin E. The study found that among those taking more than 400 IU of vitamin E daily there were 39 additional deaths per 10,000 people. A similar analysis by the federal Agency for Healthcare Research and Quality (AHRQ) concluded, "There is little evidence that vitamin E supplementation results in a reduction in cardiovascular mortality."

Most recently, the Physicians' Health Study II tested 400 IU of vitamin E among 14,641 men over age 50, concluding, "These data provide no support for the use of these supplements for the prevention of cardiovascular disease in middle-aged and older men." Vitamin E showed no effect on incidence of major cardiovascular events, heart attack or cardiovascular mortality, and actually increased risk of hemorrhagic stroke compared to placebo. (See the February 2009 Healthletter.)

The highest amount of vitamin E in multivitamins we looked at was 100 IU (333% of the DV), found in Holista MultiPure 50+, Mega-Men 50 Plus and Rainbow Light 50+.

The claim: Vitamin E and selenium "support prostate health."

It would be hard to come up with a multivitamin claim more clearly at odds with current science. Early last year, the National Cancer Institute (NCI) pulled the plug on a major trial of selenium and vitamin E's possible benefits against prostate cancer because of an absence of benefit from either supplement. In fact, men in the vitamin E group (400 IU) had a statistically nonsignificant increased risk of prostate cancer, and those assigned to selenium pills (200 micrograms) had a slightly raised risk of type 2 diabetes. (See the February 2009 Healthletter.)

An earlier NCI study actually found that men who overdid multivitamins — taking them more than once a daily — may be increasing their risk of advanced prostate cancer by about 30%. In particular, those with a high intake of selenium saw a 37% greater risk of localized prostate cancer.

The highest selenium level in men's multivitamins we looked at was 200 micrograms (286% of DV), in Nature's Bounty Your Life Men's 45+. But the highest overall was actually in a women's multivitamin, SuperNutrition Simply One 50+ Women High Energy (225 micrograms).

Other Added Nutrients The claim: Antioxidants "help protect cells from the harmful effects of free radicals."

While this claim includes common antioxidant vitamins, multivitamin makers also soup up their products with more exotic antioxidants such as hesperidin complex and quercitin. And the claims for ingredients such as açai berry, grapeseed extract and various other "botanicals" largely rest on their antioxidant activity.

"Free radicals" are highly reactive atoms or groups of atoms formed in chemical reactions involving oxygen. It's true that, by definition, antioxidants inhibit the potentially cell-damaging actions of free radicals. But science is still debating how this affects human health and whether "more is better" when it comes to antioxidants. Paul E. Milbury, PhD, of Tufts' HNRCA Antioxidants Laboratory and author of Understanding the Antioxidant Controversy (see the May 2008 Special Supplement), cautions, "The research regarding antioxidant mechanism as being the primary beneficial mechanism of the 'antioxidant' vitamins remains theoretical and has not been proven unequivocally in humans."

Given the plenitude of antioxidants readily available from food — where they come packaged with fiber and other nutrients — you may not need extra in your multivitamins unless you have a medical condition that requires more than you can get from a healthy diet.

The claim: Lutein "promotes eye health."

Lutein, along with another carotenoid, zeaxanthin, sometimes also added to multivitamins, is currently being tested against AMD in a new phase of the AREDS research. Results from prior studies are mixed. Allen Taylor, PhD, director of Tufts' HNRCA Laboratory for Nutrition and Vision Research, says, "Our data indicate that if there is a benefit, it probably requires about 6 milligrams per day" — far more than the amounts in multivitamins that boast "lutein for eye health." The highest amount we found was 1 milligram in Rainbow Light 50+; most had only a quarter as much.

The claims: Lycopene for "heart health" and "prostate protection."

Another carotenoid, lycopene is best known as the ingredient in tomatoes associated with possible heart-health benefits. A small 2007 Finnish study showed that people on a high-tomato diet who elevated their lycopene levels lowered their LDL ("bad") cholesterol by 13%. Lycopene is also currently being studied for possible blood-pressure lowering effects.

A 2004 review that analyzed 21 observational studies concluded that tomato products appear to have a weak protective effect against prostate cancer. A recently completed NCI clinical trial is investigating whether lycopene from food sources could help protect against prostate cancer; results have not yet been published. In the meantime, the American Cancer Society advises, "Further research is needed to find out what role, if any, lycopene has in the prevention or treatment of cancer. It is likely that the preventive effect of diets high in fruits and vegetables cannot be explained by just one single part of the diet."

The claims: Omega-3s/fish oil for heart health and "mental and visual functioning."

There's strong evidence that omega-3 fatty acids from fish oils have cardiovascular benefits, and some studies have suggested omega-3s may also help protect the aging brain and prevent AMD. So the question for multivitamins with extra omega-3s isn't whether omega-3s are good for you, but whether the amounts are enough to make such products worth seeking out.

Three ounces of cooked salmon contain about 1.8 grams of the two most important omega-3s found in fish, DHA and EPA. Rite Aid Whole Source Mature Adult multivitamins, whose marketing boasts of the DHA content, contains just 0.5 milligrams of omega-3s — less than l/3,000th the amount in a serving of salmon.

Herbs and Other Extracts The claim: Ginkgo biloba for "memory and concentration."

The longest prevention trial to date of ginkgo biloba recently failed to show any benefit from this herb in reducing the risk of dementia or Alzheimer's disease. (See the February 2009 Healthletter.) The Ginkgo Evaluation of Memory (GEM) study was a six-year, randomized, placebo-controlled clinical trial — considered the "gold standard" of medical research — of 3,069 volunteers age 75 or older. Researchers concluded, "Based on the results of this trial, ginkgo biloba cannot be recommended for the purpose of preventing dementia." An accompanying editorial added, "The GEM study adds to the substantial body of evidence that ginkgo biloba extract as it is generally used does not prevent dementia in individuals with or without cognitive impairment and is not effective for Alzheimer disease."

It's worth noting, too, that study participants received either a twice-daily placebo or a 120-milligram dose of ginkgo biloba. Only two multivitamins we looked at contained 120 milligrams in a daily dose — One-A-Day 50+ Advantage, both the men's and women's versions.

The claim: Ginseng "to help improve physical and mental performance, increasing resistance to stressful conditions."

Although more study is needed, ginseng has been found to be potentially beneficial for a wide range of conditions, including heart disease, high blood sugar and diabetes. The evidence remains unclear for other claims, including effects on dementia, fatigue, mental performance and overall well-being, according to the NIH/NLM. Doses in studies that have shown ginseng benefits range from 100-400 milligrams daily. Many multivitamins that include ginseng do not disclose amounts; Rite Aid Whole Source Mature Adult contains 25 milligrams.

The claim: Saw palmetto benefits prostate health.

Although some 2.5 million American men take saw palmetto extract as a treatment for enlarged prostate (also known as benign prostatic hyperplasia or BPH) and several men's multivitamins have added it, a 2006 clinical trial found no difference in benefits between saw palmetto extract and a placebo. (See the May 2006 Healthletter.) Participants not on placebo took 160 milligrams of saw palmetto twice daily. (Among senior multivitamins only Mega Men 50 Plus contains that much in a daily dose.)

The National Center for Complementary and Alternative Medicine (NCCAM), which co-sponsored that study, advises, "There is not enough scientific evidence to support the use of saw palmetto for reducing the size of an enlarged prostate or for any other conditions." Several additional clinical trials, however, are underway or have recently been completed but have not yet published results.

The claim: Bilberry for eye health.

This relative of the blueberry has a long tradition of medicinal uses, but the evidence that bilberry extract is effective against cataracts, retinopathy or glaucoma is unclear, according to the NIH/NLM. Recent studies have largely overturned earlier research suggesting bilberry might improve night vision.

Traditional doses of bilberry call for 55 to 115 grams of fresh berries three times daily or 80 to 480 milligrams of aqueous extract three times daily — far more than the amounts added to multivitamins such as SuperNutrition (25 milligrams).
The claim: Probiotics to improve digestion.

Bacteria such as Lactobacillus acidophilus live naturally in the human digestive system, where they produce vitamin K, lactase and various anti-microbial substances. The notion of giving your digestive bacteria some reinforcements has become popular in food products and even in some multivitamins. But such "probiotic" uses of acidophilus are not sufficiently studied to form clear conclusions, according to the NIH/NLM. A 2005 report from a conference co-sponsored by NCCAM and the American Society for Microbiology was more positive, citing "encouraging evidence" that specific probiotic formulations might be useful to treat diarrhea (especially from rotovirus), irritable bowel syndrome (IBS) and intestinal infections.

Most studies have measured the amount of probiotics tested by the number of live bacteria; one study, however, used capsules containing 1,500 milligrams of acidophilus. Typical stand-alone supplements contain far less, 13-15 milligrams. And Nature's Bounty Your Life multivitamins for ages 45-plus contain even less, 5 milligrams of acidophilus.

Too Much of a Good Thing?

Another factor that multivitamin makers use to differentiate their products from the competition is what they leave out. Some multivitamins targeted at seniors note that they are free of iron, a few omit vitamin K, and some (Rainbow Light Active One Senior Multivitamin) don't have either iron or vitamin K. Is this something you should check for on multivitamin labels?

Maybe so. Richard J. Wood, PhD, formerly director of Tufts' HNRCA Mineral Bioavailability Laboratory and now at the University of Massachusetts, warns that seniors may be overdosing on iron, which can increase the risk of heart disease. His research has found that 12% of the elderly participants had worrisome levels of iron. "Hardly anyone had iron-deficiency anemia," he noted, "but 16% were taking iron-containing supplements."

Iron levels vary widely among multivitamins; most we looked at have zero iron, even if the label doesn't boast about that fact, while the highest was 18 milligrams (100% of DV). Ask your physician if you should be picking a multivitamin with less iron.

Vitamin K, which has a variety of health benefits, helps blood to clot, so it can change the way blood thinners such as warfarin (Coumadin) work. According to Sarah L. Booth, PhD, director of Tufts' HNRCA Vitamin K Laboratory, if you're taking warfarin it's important to keep your diet consistent by getting the same amount of vitamin K from week to week. That includes vitamin K from foods as well as from multivitamins. If you're taking warfarin, make sure your physician knows if you're also taking a multivitamin containing vitamin K.

Vitamin E can also change how warfarin works, and herbal supplements should not be taken with warfarin. That includes the herbal extras that may be hiding in your multivitamin, particularly ginkgo biloba.

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