More on Multivitamins -- How They Do Not Work

February 9, 2009, 4:42 pm
Study Finds No Benefit From Daily Multivitamin
Multivitamins are the most commonly used diet supplement, but new research shows that daily multivitamin use doesn’t ward off cancer or heart disease.
In a study of 161,808 women who were part of the government-funded Women’s Health Initiative research effort, doctors from 40 centers around the country collected data on multivitamin use. While research shows that people who eat nutrient-rich diets filled with fruits and vegetables have lower rates of heart disease and cancer, it hasn’t been clear whether taking a daily supplement results in a similar benefit.
After following the women for about eight years, they looked at rates of various cancers and heart problems among the 42 percent of women who were regular multivitamin users, and compared them to those who didn’t take vitamins. The researchers found no evidence of any benefit from multivitamin use in any of 10 categories studied, including no differences in the rate of breast or colon cancer, heart attack, stroke, blood clots or mortality. The findings were published in the current issue of the Archives of Internal Medicine.
The finding that multivitamins produced no benefit in such a large, well-regarded study is disappointing, given that some earlier research has produced mixed results. While some earlier studies failed to show a benefit of daily multivitamin use, other research has suggested a possible benefit for colon and breast cancer and cardiovascular disease. However, those data were collected from less rigorous studies, and researchers say the lack of a benefit measured in the Women’s Health Initiative is a “robust finding.” In the tightly controlled W.H.I. trials, data from women were copiously collected, and participants actually brought vitamin bottles to W.H.I. centers so supplement use could be confirmed by researchers.
“We have very detailed information on what people were taking measured over a period of many years,” said Marian Neuhouser, the lead author and associate member in cancer prevention at the Fred Hutchinson Cancer Research Center in Seattle. “We thought there could be a modestly reduced risk, but there is nothing. There is no helpful benefit, but they’re not hurting either.”
About half of all Americans use some form of vitamin or dietary supplement, spending $20 billion annually on the products. In a statement, the vitamin industry trade group, the Council for Responsible Nutrition, said the study shouldn’t dissuade consumers from using multivitamins, since many of them aren’t getting essential nutrients in their diets.
“From a practical standpoint, this study does not change the fact that the majority of consumers could benefit from taking an affordable multivitamin,” said Andrew Shao, vice president of scientific and regulatory affairs with the council. “It is better to meet these recommendations than not, and consistently taking a multivitamin over the long term could help fill these nutrient gaps and may help consumers lead healthier lives.”
Dr. Neuhouser said she realizes that many people who are devoted vitamin users will be skeptical of the finding that they are receiving no benefit from a daily multivitamin.
“I don’t want to disparage people who take multivitamins — it’s their choice as a consumer,” Dr. Neuhouser said. “What we’re presenting is the science showing it’s neither beneficial nor harmful. If they want to choose to spend their dollars elsewhere this might be a good place to do so. Perhaps they can buy more fruits and vegetables.”
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