The study focused on 11,000 adults, 25 to 74, who provided detailed reports on their diets and lifestyles during the early ’70s. Researchers followed the subjects for 10 years. By grouping the participants according to vitamin C intake and comparing their death rates, epidemiologist James Enstrom and his colleagues found that those consuming the most lived the longest. Men in the highest-intake group (roughly 300 milligrams each day from food and supplements) suffered 41 percent fewer deaths during the study than those with the lowest intake (less than 50 milligrams a day). The discrepancy translates into roughly six years of added life span. The results were less striking for women: those with the highest intake suffered just 10 percent fewer deaths than for those with the lowest. Heart disease declined in both sexes as vitamin C intake rose.
The question is whether vitamin C is the true cause of the good things associated with it. Skeptics like Dr. Victor Herbert, a nutritional expert at New York’s Mt. Sinai School of Medicine, note that the people who get plenty of C tend to take care of themselves in other ways as well. “The reason the supplement users lived longer is that they weighed less, smoked less, exercised more and ate more fruits and vegetables,” he says. Though Enstrom doesn’t rule out that possibility, his findings held up when he corrected for 10 such factors. And as he likes to remind critics, no study has ever suggested that other dietary changes, such as lowering cholesterol, can reduce mortality by the margins seen in this study. Since a little extra vitamin C is harmless at worst, the health-conscious consumer should be sure to ask for a twist in his martini.
