Dietary Supplements: More is Not Always Better

National Institute on Aging

Bill's retired and lives alone. Often he's just not hungry or is too tired to fix a whole meal. Does he need a multi-vitamin or one of those dietary supplements he sees in ads everywhere? He wonders if they work - will one help his arthritis, or another give him more energy? And, are they safe?

"Dietary supplements" used to make you think only of vitamins and minerals. But, today this big business makes and sells many different types of dietary supplements that have vitamins, minerals, fiber, amino acids, herbs, or hormones in them. Supplements come in the form of pills, capsules, powders, gel tabs, extracts, or liquids. Sometimes you find them added to drinks or energy bars. They might be used to add nutrients to your diet or to prevent health problems. You don't even need a prescription from your doctor to buy dietary supplements.

Do I Need a Dietary Supplement?

Ads for supplements seem to promise to make you feel better, keep you from getting sick, or even help you live longer. Often there is little, if any, scientific support for these claims. In fact, some supplements can hurt you. Others are a waste of money because they don't give you any health benefits.

So, should you take a supplement? You might want to talk to your doctor or a registered dietitian to answer that question. A friend or neighbor, or someone on a commercial shouldn't be suggesting a supplement for you.

Are These Supplements Safe?

Are you thinking about using dietary supplements? Remember that these "over-the-counter" substances are not like the penicillin or blood pressure medicine your doctor might prescribe for you. The U.S. Food and Drug Administration (FDA) has to check prescription drugs to make sure they are safe and do what they promise before they are sold. The same is true for "over-the-counter drugs" like cold and pain medicines. It is not the FDA's job to check dietary supplements in the same way. That means they are not reviewed by the FDA before being sold, but it is the FDA's job to take action against unsafe products on the market. Only if enough people report problems with a dietary supplement, can the FDA study these possible problems and take action.

Besides the FDA, many federal government agencies and private groups are interested in dietary supplements. The National Institutes of Health (NIH) is the federal focal point for medical research in the United States. NIH supports research studies looking at the safety and helpfulness of some of the ingredients found in many supplements.

Business and consumer groups are also interested in dietary supplements. So are private professional groups such as the National Academy of Sciences (NAS). The NAS develops guidelines saying how much of each vitamin and mineral people need.

What About Vitamins and Minerals?

Vitamins and minerals are nutrients found naturally in food. We need them to stay healthy. The benefits and side effects of many vitamins and minerals have been studied.The best way to get vitamins and minerals is through the food you eat, not any supplements you might take. Try to eat the number of servings of food recommended by the U.S. Department of Agriculture's Food Guide Pyramid each day (see chart). Pick foods that are lower in fat and added sugars. If you can't eat enough, then ask your doctor if you should be taking a multivitamin and mineral supplement. And remember:

The supplement doesn't need to be a "senior" formula.
It shouldn't have large or "mega-doses" of vitamins and minerals.
Generally store or generic brands are fine.

How much should you take? The NAS has developed recommendations for vitamins and minerals. Check the label on your supplement bottle. It shows the level of vitamins and minerals in a serving compared with the suggested daily intake.

For example, a vitamin A intake of 100% DV (Daily Value) means the supplement is giving you the full amount of vitamin A you need each day. This is in addition to what you are getting from your food.

Some people might think that if a little is good, a lot must be better. But, that doesn't necessarily apply to vitamins and minerals. Depending on the supplement, your age, and your health, taking more than 100% DV could be harmful to your health. Also, if your body cannot use the entire supplement you take, you've wasted money. Finally, large doses of some vitamins and minerals can also keep your prescription medications from working as they should.

How Many Servings Do You Need?

Bread, cereal, rice, and pasta-6 to 11 servings

Vegetables-3 to 5 servings

Fruits-2 to 4 servings

Milk, yogurt, and cheese-2 to 3 servings

Meat, poultry, fish, dry beans, eggs, and nuts-2 to 3 servings

Fats, oils, and sweets-use sparingly

Anything Special For People Over 50?

Even if you eat a good variety of foods, if you are over 50, you might need certain supplements. Talk to your doctor or a registered dietitian. Depending on your needs, he or she might suggest you get the following amounts from food and, if needed, supplements:

Vitamin B12-2.4 mcg (micrograms) of B12 each day. Some foods, such as cereals, are fortified with this vitamin. But, up to one-third of older people can no longer absorb natural vitamin B12 from their food. They need this vitamin to keep their blood and nerves healthy.
Calcium-1200 mg (milligrams), but not more than 2500 mg a day. As you age, you need more of this and vitamin D to keep bones strong and to keep the bone you have. Bone loss can lead to fractures, mainly of the hip, spine, or wrist, in both older women and men.
Vitamin D-400 IU (international units) for people age 51 to 70 and 600 IU for those over 70, but not more than 2000 IU each day.
Iron-extra iron for women past menopause who are using hormone replacement therapy (men and other postmenopausal women need 8 mg of iron). Iron helps keep red blood cells healthy. Postmenopausal women who use hormone replacement therapy may still experience a monthly period. They need extra iron to make up for that loss of blood.
Vitamin B6-1.7 mg for men and 1.5 mg for women. This vitamin is needed for forming red blood cells and to keep you healthy.

What Are Antioxidants?

You may have heard about the possible benefits of antioxidants, natural substances found in food. Right now, there is no proof that large doses of antioxidants will prevent chronic diseases such as heart disease, diabetes, or cataracts. Eating fruits and vegetables (at least five servings a day) rather than taking a supplement is the best way to get antioxidants. Vegetable oil and nuts are also good sources of some antioxidants. Non-dairy calcium sources are especially good for people who cannot use dairy products.

Sources of Calcium

dairy products like milk and cheese and foods made with them,
canned fish with soft bones like salmon and sardines,
dark green leafy vegetables,
calcium-fortified products such as orange juice, and
breads and cereals made with calcium-fortified flour.

What About Herbal Supplements?

You may have heard of ginkgo biloba, ginseng, Echinacea, or black cohosh. These are examples of herbal supplements. They are dietary supplements that come from certain plants. It's easy to think they are safe because they come from plants. And, although herbal supplements are not approved as drugs, some are being studied as possible treatments for illness. But, it's still too soon to tell. Remember some strong poisons like hemlock and prescription medicines such as cancer drugs come from plants as well. You need to be careful.

When you use any dietary supplement, including herbals, for a health problem, you are using that supplement as a drug. Because their ingredients may have an effect on your body, they can interfere with medications you may already be taking. Some herbal supplements can also cause serious side effects such as high blood pressure, nausea, diarrhea, constipation, fainting, headaches, seizures, heart attack, or stroke.

What's Best For Me?

If you are thinking about using dietary supplements for any reason, remember:

Talk to your doctor or a registered dietitian. Just because something worked for your neighbor, doesn't mean the same will be true for you.
Use only the supplement your doctor or dietitian and you decide on-don't buy combinations that have things you don't want or need.
If your doctor does not suggest a dietary supplement, but you decide to use one anyway, tell your doctor. Then he or she can keep an eye on your health and adjust your other medications if needed.
Learn as much as you can about the supplement you are thinking about, but be aware of the source of the information. Could the writer or group profit from the sale of a particular supplement?
Buy brands you know from companies you, your doctor, your dietitian, or your pharmacist know are reputable.

Remember that many of the claims made about supplements are not based on enough scientific proof. If you have questions about a supplement, contact the firm and ask if it has information on the safety and/or effectiveness of the ingredients in its product.

What Else Can I Do?

Here's what one active older person does:

When Pearl was nearing 60, she was concerned about remaining healthy and active as she aged. She began to exercise. Now she takes a long, brisk walk 3 or 4 times a week. In bad weather, she joins the mall walkers at the local shopping mall. In good weather, she also works in her garden. She had long since stopped smoking. Pearl tries to follow a healthy diet. She reads the newspaper everyday. She's even learning how to use a computer and keeps in touch with her family by email, as well as phone calls. She always wears a seatbelt when in a car. Last month, she danced at her granddaughter's wedding. Pearl is now 84 years old.

Try following Pearl's example-stick to a healthy diet, exercise, keep your mind active, don't smoke, and see your doctor regularly.

National Institute on Aging U. S. Department of Health and Human Services National Institutes of Health August 2002

Web page last updated: December 29, 2005