Meir Stampfer, MD, a professor of epidemiology and nutrition at the Harvard School of Public Health in Boston, also believes the research was flawed. "It combined results from very disparate studies, including many that were short and that varied the dose of the vitamin," Stampfer says. And the dosages reviewed were extremely high. On average, study participants swallowed 20,219 IUs of vitamin A—nearly ten times the official daily recommendation; the vitamin C group took almost seven times as much.
So what's a health-conscious, supplement-swallowing woman to do? "You shouldn't make lifestyle decisions based on the research du jour," Blumberg emphasizes. "Listen to experts who consider the entire body of research." He and Stampfer both believe that most women need nothing more than a daily multivitamin and a calcium-plus-vitamin-D supplement. Though healthy foods like fruit, veggies, beans, low-fat dairy, and whole grains should be your primary source of nutrients, Americans often fail to get recommended amounts of many essential vitamins and minerals. The multivitamin will ensure that you do. "These supplements are affordable and effective," Blumberg says. "They reduce your risk for osteoporosis and for birth defects in infants—huge benefits for pennies a day."