5 Myths About Nutritional Supplements

08/24/2012 10:57 am ET


By Debra Witt


There’s a reason many supermarkets and drug stores devote an entire aisle to nutritional supplements. For those of us on a quest for better health, it's hard to resist the promise that it can be delivered in the form of neatly packaged pills.

One in three American adults takes at least one dietary supplement each day, reports the Office of Dietary Supplements at the National Institutes of Health. Overall, Americans spend more than $11 billion annually on vitamins and minerals, according to the most recent government figures.

"There’s so much interest in nutrition today," says dietitian Joan Salge Blake, a professor at Boston University and a spokesperson for the Academy of Nutrition and Dietetics. "Baby boomers, especially, are interested in living longer and better than the generation before. They are savvy about seeking out information; they follow health news and use the Internet to learn more. I think many are willing to do whatever it takes to stay healthy."

Enter supplements. Most healthy adults can benefit from a multivitamin and one or more single-ingredient supplements, says dietician Elizabeth Somer, author of "Eat Your Way to Sexy" (Harlequin, 2011). The problem, though, is that too many of us are simply guessing about our needs, based on what we see in headlines or hear from friends. Here, Salge Blake and Somer clear up some widespread myths about what supplements can do for you and share tips for making sense of product labels and claims.

Myth: Supplements can help prevent or manage conditions like diabetes or heart disease.

Fact: Supplements aren’t intended to treat any specific health issue.

Nutritional supplements are not medications. They "fill in the nutritional gaps" in a well-rounded diet, Somer says. "Nothing more." They help us reach daily nutritional needs that are tough to meet with food alone. Vitamin D is a good example, because it’s not found in many whole foods. Supplements can be one piece of the puzzle in helping us prevent illness, although exercising and eating right are both more crucial.

Myth: Supplements can make up for your diet's flaws.

Fact: You still need a well-rounded diet.

"Supplements can’t replace a healthy diet," Salge Blake says. "You need to look at them as a tool, something you take on top of eating right.” When healthy adults get most of their nutrients from their food, they can generally trust their bodies to absorb what they need. When you rely on supplements instead, however, you run the risk of taking in too much, which can be harmful to your health. For example, too much vitamin A can increase your risk of osteoporosis; too much vitamin E can elevate your risk of suffering a stroke; and too much iron can raise your risk of heart disease. Excesses of these nutrients are stored in fat and are not excreted, so they can build up in the body and become toxic. If you're already eating plenty of fruits and vegetables and consuming fortified cereal, yogurt, juice or milk, you may not need multivitamins or individual supplements on top of that.

Further, if you don't take a supplement properly, which starts with taking it with your meals, there’s a good chance your body will simply excrete most of it. When we eat whole foods, our body's digestive system very efficiently takes out certain nutrients along the way -- B vitamins at one point, calcium at another, etc. -- and excretes much of what's not needed. When you take a supplement, though, your stomach acids have to do all the work, dissolving the pill and sending nutrients back out to the various body parts. It's less efficient. When you take supplements with food, the nutrients in the pill bond with the food and you get the best delivery and absorption.

Still, even taken properly, supplements can't supply all the benefits of healthy eating. That includes delivering many phytonutrients, the chemicals available in fruits and vegetables that have been shown to have potential health benefits, such as resveratrol, flavonoids and carotenoids. "Researchers have found about a million phytonutrients that you simply can’t get in a supplement," Somer says. These nutrients, available in many antioxidant-rich foods, may support your immune system and improve communication between cells, among other benefits still being discovered.

Myth: The best supplements are those labeled "all natural."

Fact: The only part of the label that matters is the nutrition facts.

Like other food sellers, supplement manufacturers are eager to capitalize on heightened consumer interest in natural foods by touting their "all natural" bona fides, such as the addition of ingredients like enzymes or primrose oil. In most instances, though, none of these provide real benefits to the consumer because they're added in only minute or trace amounts, Somer says. "They are just adding extra costs."

What you should pay attention to is the nutrition information panel on the label. All of the nutrients contained in a supplement, Somer says, should be listed as providing "around 100 percent, but no more than 300 percent," of the daily recommended value (DV). Those percentages are generally considered to represent a safe dose. (In most cases, ingredients listed with a higher than 100 percent dose are there to aid with the absorption of other nutrients, or, like vitamin C, are water soluble and so will not build up to toxic levels in your body.)

Myth: When you hear a nutrient has new proven health benefits, it's time to stock up.

Fact: The supplement may not be right -- or safe -- for you.

"People think that because you can buy these products over the counter they’re benign, but that’s not the case," Salge Blake says. "Be wary of any vitamin or nutrient that gets buzz. Studies break all the time, but that’s one grain of sand on a beach of research."

Before investing in a supplement that you hear will fight off one or another chronic condition, talk to your doctor or a dietitian to find out if it's worth it, especially if you have a medical condition that could be compromised by large doses of certain nutrients. For example, people who take blood thinners or aspirin need to be wary of both vitamin E and omega-3 supplements, which could limit the blood's ability to clot and increase your risk of bleeding. "Getting those nutrients from food is not a concern," Salge Blake says, but the concentrated doses in supplements could lead to excess.

It's also wise to factor in the nutrients you’re already getting from foods. For example, it may be unnecessary or even harmful to take a daily multivitamin if your morning bowl of cereal has already been fortified with 100 percent of the daily value of the same vitamins and minerals.

Myth: Multiple single-source supplements are better than multivitamins.

Fact: For healthy adults, a multivitamin is sufficient (with some exceptions).

The vitamin and mineral needs for most adults over 50 can be met with a multivitamin with extra B12, which is beneficial for neurological function and red blood cell formation, and which our bodies tend to absorb less well from foods as we grow older. There are, however, a few exceptions in which a single-source supplement could be beneficial -- these include calcium, magnesium, vitamin D and omega-3. "No daily multivitamin will have enough of those ingredients," Somer says, adding that most of us don't get enough of them through our diets either.

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