By Margarita Nahapetyan
The largest study ever of multivitamin use in older women found no evidence that using pills can prevent postmenopausal women from developing heart disease and common cancers.
Half of all Americans take vitamins and other dietary supplements on a regular basis, and multivitamins are the most commonly used, the authors write in the Archives of Internal Medicine journal. "People want to take control of their health," says lead author of the study Marian Neuhouser, an associate member of the Public Health Sciences Division at Seattle's Fred Hutchinson Cancer Research Center. "Taking a multivitamin kind of empowers people, because they are in charge of that behavior."
Researchers said that taking multivitamins doesn't appear to do any harm, but at the same time they do not bring any benefits either. It would be much better if older women focus more on eating a healthy and balanced diet, instead of trying to get their nutrients from a multivitamin pill, they advised.
"The kind of vitamins you get from diet is quite different, because foods are very complex and have a lot of chemicals we don't know about that interact with each other. Eating a varied diet is not the same as distilling it into a pill. The message is to eat a well-balanced diet, exercise and maintain weight," said study co-author Sylvia Wassertheil-Smoller, a professor of epidemiology and population health at the Albert Einstein College of Medicine in New York.
For the study, Neuhouser and colleagues analyzed 161,808 women who were taking part in the Women's Health Initiative (WHI) clinical trials. 68.132 women (more than 40 per cent) were enrolled in clinical trials of hormone therapy, dietary interventions, and calcium and vitamin D supplements, and 93.676 (less than 60 per cent) of them took part in an observational study. Of all, nearly 42 per cent of participants reported using multivitamins. The researchers followed the women, who enrolled between the years of 1993 and 1998, for nearly eight years in order to track the health effects of taking multivitamins.
After taking into consideration such factors as age, physical activity, family history of cancer and many other factors, Wassertheil-Smoller and her colleagues found that multivitamin intake played almost no role in the health of all participants. There appeared to be no association between multivitamin use and risk of breast, colorectal, endometrial, lung or ovarian cancers, as well as risk of cardiovascular disease, heart attack, stroke, blood clots or overall death.
After the 8-year period of the study there were: 9,619 cases of breast, colorectal, kidney, endometrial, bladder, stomach, lung and ovarian cancer, 8,751 cardiovascular events, such as myocardial infarction (heart attack), stroke, and venous thromboembolism (blood clot), and 9,865 cases of mortality.
The results revealed that women who used multivitamins and dietary supplements led more or less healthy lifestyle, were more likely to be white, had a lower body mass index, were more physically active and had a higher level of education, compared to women who did not take vitamins. Also, women who used multivitamins were more likely to consume alcohol and less likely to smoke, and they confirmed eating more fruits and vegetables and eating less fat than non-users. The scientists say, however, that more research is needed to find out as to how vitamins would affect women who eat poorly. Other things about diet that were not examined in the study include sense of energy and well-being.
The results coincide with those of other studies that also found no health benefits for older women from using multivitamins. However this Women's Health Initiative study is more definitive said Neuhouser, because: "We have such a large and diverse sample size, including women from 40 sites across the nation, our results can be generalized to a healthy population."
In a statement responding to the study, Andrew Shao, PhD, the vice president for scientific and regulatory affairs at the Council of Responsible Nutrition, a trade group for the dietary supplements industry, said that "Multivitamins, like all other dietary supplements, are meant to be used as part of an overall healthy lifestyle; they are not intended to be magic bullets that will assure the prevention of chronic diseases, like cancer... From a practical standpoint, this study does not change the fact that the majority of consumers could benefit from taking an affordable multivitamin, particularly as the majority of Americans fail to consume the recommended amounts of a variety of essential nutrients established by the Institute of Medicine."
The Women's Health Initiative is one of the largest prevention studies in the United States that has ever been done on diet and health. It is looking at the most common causes of death, disability and impairments to quality of life in postmenopausal women.