Vitamins and Minerals: Who Needs Supplements?

How do we know if we need to take a vitamin or mineral supplement? With all the conflicting information now available, it's more important than ever to sort the reliable information from the questionable. Despite the beliefs of those who take a handful of supplements every morning, there are relatively few supplements that are essential to good health, says Joan Pleuss, RD, MS, CDE, CD.

Pleuss, a Bionutritionist at the Medical College of Wisconsin Clinical Research Center, says that eating well is the best way to get our vitamins and minerals. But she advises several groups of people to take specific supplements.

"All women of childbearing age should take a folic acid supplement," she advises. "Studies are showing that 400 micrograms of folic acid per day decreases the risk for neural tube birth defects, one of those being spina bifida. Folic acid is a very simple measure for women to take to prevent that from occurring."

Even if a woman isn't pregnant or is using contraceptives to prevent a pregnancy, unplanned pregnancies still happen, and neural tube defects occur within the first few days of pregnancy - usually before women know they're pregnant. "That's why we recommend folic acid for all women of childbearing age," says Pleuss. "The easiest way for women to get enough folic acid is to take a multivitamin or prenatal vitamin, and they're getting other vitamins and minerals as an insurance factor." Additionally, many foods are fortified with folic acid.

Pleuss also recommends supplements for post-menopausal women. "Post-menopausal women need vitamin D and calcium," she says. "Multiple vitamin and mineral supplements have some calcium, but not very much, so if they're not getting enough calcium in their diet they usually have to take another calcium supplement." The need for calcium goes up from 1000 milligrams in pre-menopausal women to 1200 milligrams after menopause.

Vitamin D should accompany calcium, as it is essential for the absorption of calcium. "When women reach age 50, the recommended amount of vitamin D goes up from 200 to 400 IUs. Then at age 70, it goes up from 400 to 600," says Pleuss. "Your need for supplemental vitamin D also depends upon where you live, as vitamin D is made by the body after being in the sun. In certain climates we don't see the sun very often, and at some latitudes, even if the sun is out, we might not be getting the full benefit of it."

In addition to women of childbearing years and post-menopausal women, Pleuss says men and women over the age of 50 should take a vitamin B12 supplement. "When people reach the age of 50, the amount of acid they have in their stomachs starts to decrease," explains Pleuss.

"Vitamin B12 is only found in animal sources, and it's 'bound,' which means it has to be broken away from the protein in the sources. That's one of the functions of stomach acid, so as stomach acid decreases, less vitamin B12 is available to the individual." As people begin to lose their ability to break down vitamin B12, they can become deficient. Pleuss adds, "One of the symptoms of a vitamin B12 deficiency mimics certain mental deficits, so a person can be thought to have Alzheimer's disease, when actually it's a simple vitamin deficiency."

"Essentially," says Pleuss, "we're talking about half the population who should be taking a supplement - women of childbearing age and postmenopausal women. Then everyone over age 50 gets B12. So it's only adult men under 50 who don't need to be taking a supplement, and then only if they're eating well."

Special Conditions
Groups of people with special conditions might need supplements as well. "During pregnancy, most physicians will prescribe a prenatal vitamin with iron," says Pleuss, "because there's an increased need for vitamins and minerals at that time."

People who eliminate animal products from their diet often need vitamin B12. "Vitamin B12 comes only from animal sources," says Pleuss, "so people who don't eat animal products need to eat foods that are fortified with B12 or take a supplement."

People who smoke and people who drink more than one alcoholic drink per day might need supplemental vitamins and minerals as well. Pleuss explains, "They have an increased need for some nutrients, so it's a good idea for them to take a multiple vitamin and mineral supplement, as well as trying to correct their habits."

For people with chronic conditions or lowered immunity, Pleuss recommends consulting a physician. "Particularly if you're receiving treatment for cancer, you need to be concerned with the interaction of medication with supplements. Sometimes they can actually be detrimental to the effects of chemotherapy."

Supplements for Occasional Use
As far as taking extra vitamin or mineral supplements for a cold or to prevent illness, Pleuss says there's no hard evidence that it will work. "There's some evidence that taking vitamin C can shorten your cold by a day or so, but vitamin C in larges doses, 2000 milligrams and above, can cause diarrhea, so you have to weigh the costs and the benefits."

To build immunity, Pleuss says, "Eat properly, get the appropriate amount of rest and exercise, and keep the weight under control. A healthy lifestyle is more effective than supplements." Taking an extra vitamin C or zinc tablet won't hurt, says Pleuss: "Some people swear by it, and if they feel it helps them, it's fine."

Be Careful with Long-Term Use
Some supplements call for a bit of caution, says Pleuss. Fat-soluble vitamins - vitamins A, D, E, and K - are stored in the body's fatty tissue. They build up in the body, so the more you take, the more dangerous they could be to your system. Water-soluble vitamins - folate, niacin (B3), pantothenic acid, biotin, thiamine (B1), vitamin B12, and vitamin C - must be used by the body right away. Any left over water-soluble vitamins leave the body through the urine.

Again, it's best to check with a physician or Registered Dietician before taking large doses of any vitamin or mineral supplement.

What to Look For When Buying Supplements
Before buying any vitamin or mineral supplement, says Pleuss, "It's important to read the label to make sure the vitamins and minerals do not exceed 100% of the Daily Value." The Daily Value for vitamins and minerals gives a general idea of how much of a vitamin or mineral a serving contributes to the total daily diet. For example, if the Daily Value for vitamin C of all the foods you eat in a day adds up to 100%, your diet meets the recommendation for vitamin C.

When buying quality vitamin and mineral supplements, Pleuss emphasizes, "Cost is not always a factor. The cheapest can be as good as the most expensive." She also recommends looking for either the ConsumerLab or United States Pharmacopeia (USP) stamp on the container. "The supplement companies voluntarily subject their product to analysis, and it ensures that what the label says is in there, is in there." This doesn't mean the supplement is safer or more effective than other supplements, Pleuss says, because vitamins and minerals are not regulated. It does, however guarantee that the label is correct.

An Insurance Policy
Even when taking supplements, says Pleuss, it's important to eat a wide variety of nutritious foods from the five food groups:

• Grains group, including bread, cereal, rice, and pasta
• Vegetables
• Fruits
• Dairy products such as milk, yogurt, and cheese
• Meat and beans group, including poultry, fish, eggs, and nuts

"There are lots of nutrients and different substances that we're finding in food that we didn't even know about ten years ago, which are very beneficial to us. We also don't know about the possible benefits of combinations in food that are not present in a supplement," says Pleuss.

Even when taking supplements, says Pleuss, it's important to eat a wide variety of nutritious foods. "A multiple vitamin and mineral supplement, in my opinion, is a very inexpensive thing for people to do for their health. But our goal should be to eat well. Supplements are insurance, not a replacement for eating properly."

P. J. Early
HealthLink Contributing Writer

This article contains information from the National Institutes of Health Office of Dietary Supplements and Health.gov.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.