Vitamins: Too Much of a Good Thing?

Auburn, May 9, 2003 --- Decades ago, taking aim at chronic and sometimes life-threatening diseases, the nation’s health establishment declared all-out war against vitamin and mineral deficiencies.

Now, with victory all but secured, many experts are wondering if millions of Americans are getting too much of a good thing.

One such expert is Dr. Robert Keith, an Alabama Cooperative Extension System nutritionist and Auburn University professor of nutrition and foods. Keith spares no praise of efforts starting as far back as the 1940s to fortify certain foods with essential vitamins and minerals – measures that went a long way toward reducing the incidence of serious, but once all-too-common diseases such as rickets, pellagra and goiter.

“We still find pockets here and there where vitamin and mineral deficiencies still exist, but as a whole, we just don’t see the level of deficiencies we once did,” Keith says. “We are eating better because many of the foods we’re consuming have been fortified with many of these essential nutrients.”

“Add to that fact that many people are taking vitamin supplements.”

Still, as Keith and other experts are learning, what started out as a noble undertaking to safeguard against disease has begun working against us in a few cases. 

As many food and beverage manufacturers are learning, nutrient fortification and enrichment are marketable commodities, which explains why more products than ever before are being fortified or enriched with many, if not most, of the key vitamins and minerals. As a result, millions of Americans are routinely exceeding the daily recommended allowances for many of these nutrients.

“We’re consuming things that we never imagined would have vitamins and minerals placed in them,” Keith says. “And, of course, cereals go all the way from being a little fortified to products in which you can get 100 percent of all the recommended dietary allowances (RDA) for most vitamins and minerals.”

Add to this the fact that roughly 70 percent of Americans take dietary supplements, according to a recent New York Times article. Forty percent are taking them regularly, the article also reports. 

“So we’re concerned that with some vitamins and minerals, we may have some people going in the opposite direction. Instead of being deprived of many essential vitamins and minerals, they may be getting too much of them.”

For most people, oversupplementation doesn’t pose a serious health risk. But in a few instances, the risks can be dangerous and even life-threatening.

Studies have shown, for example, that consuming vitamin A at several times the RDA can compromise bone building -- a special concern for post-menopausal women and the elderly who may be obtaining too much from daily vitamin supplements, fortified cereal products and other dietary sources, Keith says.

Pregnant women are also at risk.

“Pregnant women who exceed the RDAs for vitamin A by two or three times may place their unborn babies at serious risk of birth defects,” Keith stresses. ”This has certainly been the case with laboratory animals and is likely to be with women too.”

Again, it is a problem compounded by the easy access to supplements and vitamin A-fortified food products.

“There is a chance that a pregnant woman could be consuming well beyond the RDA for vitamin A at a very crucial time in her pregnancy,” Keith says.  “She’s may be drinking milk and eating an all-encompassing cereal and maybe even some energy bars.”

Iron enrichment is another source of concern, especially among some men who, because of genetics, have a tendency to store excessive amounts of the mineral.

“Cereals, breads, and multivitamin and mineral supplements – all of them have iron in them,” Keith stresses. “And excessive exposure to this mineral can have seriously detrimental effects in the form of liver damage and heart disease.”

Children also may face a higher risk of overexposure to some vitamins and minerals, Keith says, because of their smaller body sizes.

“Because they’re still growing and developing tissue, they’re being encouraged to eat plenty of fortified and enriched foods. But because their bodies are smaller, they may be getting too much of them in some cases.”

Keith offers these rules-of-thumb as safeguards against oversupplementation:

First, if you want to take supplements, choose only those that are at or below the recommended daily allowances for each vitamin and mineral.  You should assume that if you get 75 percent of the RDA from supplements, you’ll get the rest from other sources.

Second, if you’re already eating a cereal in the morning that is fortified with 100 percent of all of the key vitamins and minerals, you should avoid supplements entirely unless your doctor advises otherwise. 

Finally, take an inventory of the food and beverage products you’re consuming. You should consider discontinuing a few of these if you determine that you are consuming several products that are fortified with the same vitamins and minerals.

(Source: Dr. Robert Keith, Alabama Cooperative Extension System Nutritionist and Auburn University Professor of Nutrition and Foods)

 Article in MS Word

 Article in Text