= Full article availableOn the TV cartoon series “The Jetsons,” the space-age family got all its daily nutrients by popping a pill. Though we’ve learned a lot about essential nutrients since George Jetson rocketed onto the screen in 1962, two Tufts researchers caution that we’re no closer to relying on supplements instead of food now than we were then. In fact, they suggest that the benefits of food in a healthy diet may be more complex than merely delivering so many milligrams of this or that vitamin or mineral.
Writing in the Journal of the American Medical Association, Alice Lichtenstein, DSc, and Robert Russell, MD, of Tufts’ Jean Mayer USDA Human Nutrition Research Center on Aging call the advances in identifying and isolating essential nutrients “a double-edged sword. It has allowed scientists to uncover the mechanisms by which nutrients sustain life and to quickly and inexpensively treat nutritional deficiencies. However, it has also allowed the possibility that the proper balance of purified vitamins and minerals could supplant the need for a varied diet to support life.”
Research results don’t support such a switch from an emphasis on healthy eating to popping pills, they warn, adding: “If the message perceived is that nutrient supplements provide an ‘insurance policy’ against an imperfect diet, we must consider what impact this message would have on the balance of food choices and, hence, overall nutritional status.”
Lichtenstein and Russell go on to explore the seeming contradictions between healthy effects from certain dietary patterns and the findings from intervention trials of the nutrients in those same foods. For example, diets high in fruits and vegetables have been associated with decreased risk of cardiovascular disease. Eating plenty of produce and low- and nonfat dairy products appears to lower blood pressure. “However, instead of focusing on dietary patterns, most intervention trials have used high doses of single nutrients or nutrient cocktails…,” they note. “These results for the most part have been disappointing.”
They cite, for instance, “the disheartening results of the vitamin E intervention trials for the prevention of cardiovascular disease.” Similarly, high beta carotene intake was linked with a lower risk of lung cancer, particularly among smokers. But when researchers tested beta-carotene supplements, the results were either insignificant or, worse, negative—subjects taking supplements actually had higher rates of lung cancer.
High blood levels of a substance called homocysteine were associated with increased cardiovascular disease risk; folate reduces homocysteine levels. Therefore, when grain products were supplemented with folate to combat birth defects, scientists hoped for a benefit against heart disease as well. “Now their enthusiasm has been somewhat tempered as a result of new studies,” Lichtenstein and Russell write.
What’s going on? “These findings suggest that science is not at a point at which researchers can identify with relative certainty the putative compounds that are driving the food-disease relationship or the compounds that are modulating these outcomes,” they conclude. Getting the right nutrients may not be a matter of merely popping the right pills: “Nutrient and nutrient-food interactions are complex and have many facets,” say the Tufts researchers, adding that other factors such as “lifestyle behaviors, physical activity, weight control, smoking and perhaps even sleep and stress reduction affect health outcomes as much as diet.”
Even though food continues to trump supplements as the foundation of a healthy diet, the Tufts experts do cite some specific supplements that make sense for certain segments of the population. Folate is important for women of child-bearing age, as noted. As people age, they often lose some of the body’s natural ability to make vitamin D and to absorb B12, so the elderly may benefit from supplements of these nutrients, as well as calcium. The American Heart Association recommends omega-3 supplements for patients with coronary heart disease.
Otherwise, popping a pill instead of eating a balanced diet remains the stuff of science fiction. u
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