Do Multivitamins Make You Healthier?
| That's a question that many people and researchers have been considering for years. About half of all Americans take a multivitamin supplement just to make sure they are getting all the nutrients they need. They are spending in excess of $20 billion yearly. What are they getting in return for this huge investment?
The Women's Health Initiative (WHI) study includes 161,808 women. At the start of the study, researchers asked women if they were taking multivitamins and for how long. After 8 years of observation, researchers looked to see if they could find a health advantage in those taking multivitamins. They could find no link between taking multivitamins and risk of cancer, heart disease, or stroke. Neither was there any link between multivitamin use and total mortality. In some specific cases, those taking multivitamins had a slight increased risk of disease such as for non-Hodgkin's lymphoma. These results were similar to Harvard's Nurses' Health Study, in which researchers found no significant health advantage to taking multivitamins, except for a slightly lower risk for colon cancer in women taking multivitamins for more than 15 years. (Some research shows folic acid to be protective against bowel cancer.) Researchers also found a slight increased risk for fatal non-Hodgkin's lymphoma in multivitamin users.
The National Institutes of Health sponsored a conference in 2006 to evaluate the evidence for multivitamin use in relation to chronic disease. They concluded that there was not sufficient evidence to recommend taking vitamins for chronic disease prevention. They also said there was insufficient evidence to suggest that taking multivitamins increased health risks.
The American Cancer Society's guidelines on nutrition and cancer prevention do not recommend taking multivitamins. In some cases, taking multivitamins can cause health problems, such as was observed in the Nurses' Health Study. Women taking multivitamins with vitamin A were getting too much vitamin A and showed a significant increased risk for osteoporosis.
All of these studies show that if you want to improvements in your health, multivitamins are not an effective strategy. Does that mean there is never a need for vitamins? No. People with certain conditions can be helped. Here are some examples:- Women show fewer birth defects if they take folic acid before and during their pregnancy.
- People living in the northern half of the United States get inadequate vitamin D in the winter and have lower risks for several health problems if they take vitamin D supplements, at least 1,000 IU daily in the winter. Most multivitamins have such a low dose of vitamin D it has not been effective.
- As people get older they don't absorb vitamin B-12 as well. Some studies on seniors show that as many as 30 percent of the population has low vitamin B-12 levels and should be taking a vitamin B-12 supplement.
- Total vegetarians would also be wise to take a B-12 supplement. Studies show that they are often low in B-12. One study showed vegans had the lowest levels of B-12 in the group and many showed signs of brain atrophy.
- People who don't drink milk should be sure they get adequate calcium – which is not a vitamin, but a mineral. Calcium supplements can help these persons be sure they get adequate calcium.
- Some people have problems absorbing nutrients due specific health problems, such as celiac disease which can cause the villi in the gut to essentially disappear, resulting in absorption problems. These people may need extra vitamins.
While taking vitamins, for most people, will have little if any health advantage, remember there are numerous studies showing that eating healthfully does give you significant health advantages. A healthful diet means eating more fruits and vegetables; limiting animal fats, cholesterol, and sugar-laden and refined foods; and eating more whole-grain breads, unrefined cereals, nuts, and legumes. If you want better nutrition, put your money in these proven effective dietary methods. You'll get better results.
Archives of Internal Medicine. 2009;169(3):294-304.
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