There is no shortage of people who will be happy to sell you a specific supplement or food that they claim will help you live a longer and healthier life. The science behind many of these products, however, is not always convincing to some public health scientists, or epidemiologists.
"What we know is that diets rich in fruits and vegetables appear to be much healthier, leading to less chronic disease and lower healthcare costs, but it's less clear how any specific dietary items affect longevity," says Hubert Warner, PhD, associate director of the biology of aging program at the National Institute of Aging.
Warner also says that not eating much food at all, ever, may promote living longer, while also making life decidedly less enjoyable.
"Many animal studies show that calorie restriction, meaning a permanent, low-calorie diet, can lengthen life in the laboratory," says Eugenia Wang, PhD, professor of biochemistry at the University of Kentucky in Louisville, who studies the genetics of aging. Several monkey studies on calorie restriction are under way at the University of Wisconsin, according to Warner, but no human studies have been done.
So if you're looking for foods for living longer, a plant-based diet -- something very similar to what most of us would consider a vegetarian diet -- seems to be the ticket, these experts say.
"There are thousands of small, short-term studies of foods or supplements that may show a particular effect, but when you look at large, long-term studies of how diet affects longevity and healthcare costs in the real world, it is plant-based diets that actually appear to be healthier," says Neal Barnard, MD, president of the Physicians' Committee for Responsible Medicine and author of Eat Right, Live Longer: Using the Natural Power of Foods to Age-Proof Your Body and other books.
Barnard cites a study, "Ten Years of Life. Is It a Matter of Choice?" as an example of this evidence. In the study, researchers looked at 34,192 non-Hispanic, white Seventh Day Adventists over age 30.