Vitamin and mineral supplements should not replace a balanced diet, experts said.

D. Lee Alekel, assistant professor of food science and human nutrition, said it is always better to obtain nutrients from food instead of from supplements.

“There are [many] reasons we should be getting our nutrients from food, in part [due to fiber but also] the phytochemicals in foods, [some of] which have yet to be identified,” she said.

There are benefits from food which cannot be obtained from a vitamin and mineral supplement, Alekel said.

“There are [many] reasons why we shouldn’t just be looking toward pills,” she said. “We really need to be looking toward the whole food, and the more you can eat of the whole food, the better off you’ll be.”

However, Alekel said supplements can be used to obtain vitamins and minerals not present in sufficient amounts in a person’s normal diet.

“Getting nutrients from a supplement is certainly better than not getting it at all,” she said.

Unless a person has a documented deficiency, they don’t usually need to take a vitamin and mineral supplement, said Laura Elliott, clinical dietitian at Mary Greeley Medical Center.

“If they’re eating a balanced diet, we generally don’t feel that it’s necessary,” she said.

There are cases in which supplements may be necessary, said Kevin Schalinske, assistant professor of food science and human nutrition, for example, during pregnancy or for older people.

Also, women may need to take calcium supplements if they don’t get enough calcium in their normal diet, Alekel said. She said it’s not practical to try to obtain enough calcium in a multivitamin and mineral supplement, which usually contains less than 200 mg in each capsule.

Alekel said this makes it difficult for many women to obtain sufficient amounts from their diet, unless they regularly drink two to three glasses of milk a day.

“Women should be consuming about 1,200 mg a day of calcium, so you just can’t get enough [from a supplement],” she said.

Elliott said women often need more calcium because they tend to have smaller and less dense bones than men and are more likely to have fractures.

Schalinske compared taking vitamin supplements to getting a tune-up for a car. It is possible to walk all the way to Florida, but the trip is shorter driving.

“But if I don’t put anything in the car, if I don’t put the gas in the car, or the spark plugs, it’s not going to work,” he said. “It’s the same with the enzymes in your body.”

An enzyme acts as a catalyst for a given process, just as a car helps with transportation, he said. But, if there is no gas or good parts in the car, it won’t work. Likewise, vitamins and minerals are needed as catalysts to get the most out of the food eaten.

Vitamins and minerals act as co-factors to help with bodily processes, he said. For example, iron is necessary for hemoglobin to transport oxygen to the cells.

It is unnecessary to take excessive amounts of vitamins and minerals, Alekel said. She recommended buying a supplement which doesn’t have more than 100 percent of the Recommended Daily Allowance of any nutrient.

Elliott also recommended taking inexpensive multivitamins.

“If they’re wanting [trace minerals], then they need to look for that, [and] a general generic multivitamin should be adequate,” she said. “I would only [supplement] with one times the RDA unless they have some special concerns.”

Taking excessive amounts of vitamins may have negative consequences, Schalinske said. With some vitamins, such as vitamin C, megadosing will have little toxic effect, but others can harm the body.

Vitamins are classified as either water-soluble or fat-soluble, he said. Taking excessive amounts of water-soluble vitamins usually has no long-term impact. “Once we take in more than we need, we just simply excrete them,” Schalinske said.

However, fat-soluble vitamins – vitamins A, D, E and K – can accumulate in the body.

“Because they’re fat-soluble, they can be stored,” he said. “If we can store them, then there’s the potential for them to accumulate over time and be toxic.”

Vitamin A in particular can be very toxic, Schalinske said. There are various liver problems associated with vitamin A. Some prescription derivatives of vitamin A, such as Acutane, a drug used to treat acne, as well as vitamin A itself, have been known to cause birth defects, he said.

Some minerals can also harm the body, Schalinske said. For example, an iron overdose can lead to death.

“Like some of the fat-soluble vitamins, iron can be very toxic,” he said. “It is something that is given to many women, especially if they’re pregnant, or even if they’re not pregnant.”

However, Schalinske said the amounts needed to overdose on a vitamin or mineral are high enough that it isn’t normally a problem.

“There’s going to have to be some intent there [to take supplements of a specific vitamin or mineral],” he said. “It would have to be a conscious decision. You’d have to say, `I’m going to take a lot of vitamin A today.'”

Vitamin and mineral deficiencies are a problem, especially for at-risk groups, Alekel said. Alcohol use, in particular, can lead to nutritional problems.

“On every level, alcoholics are at risk for malnutrition and for deficiencies of specific nutrients,” she said.

Alcoholics have more nutritional problems for many reasons, Alekel said. Because alcoholics tend to substitute alcohol for food calories, they may have impaired digestion and absorption. They also tend to excrete more water-soluble vitamins and minerals.

People who eliminate major food groups from their diet may also be at risk for nutritional problems, she said. Vitamin E, which acts as an antioxident, is arguably the most difficult vitamin to obtain in sufficient amounts from diet alone, she said. Vitamin E protects cells against potentially-damaging byproducts of metabolism, according to the National Institutes of Health Clinical Center Web site at www.cc.nih.gov.

Plants make vitamin E, she said, and the richest sources of this nutrient are oils. However, Alekel said that as high-fat foods are trimmed from a diet, there is a risk of not consuming enough vitamin E. Some good sources of vitamin E are almond oil, corn oil, cotton seed oil, peanut butter and wheat germ oil. “Our food supply is no longer very rich in vitamin E, unless you consume oils that have been cold-pressed,” she said.

Since vitamin E is very heat volatile, oils that have been exposed to heat, or hot-pressed, such as most oils available in the supermarket, have lost much of their vitamin E activity.

Elliott said people should be prepared to spend more on a vitamin E supplement. “Price or quality only seems to matter with vitamin E,” she said. “It needs to be a natural form. The synthetic that’s produced is half as effective.”

The problem isn’t that vitamins aren’t available in foods, it’s people who don’t eat the right foods, Elliot said. For example, milk is rich in calcium, and folate is present in leafy green vegetables.

“The problem is that people aren’t eating the foods they should,” she said.