Research dating back to the 1930s has shown that calorie restriction increases lifespan in animals. Results from preliminary human trials suggest that cutting daily intake of calories by 25 to 30 percent can help humans to live longer too. (That’s dropping down to 1,400-1,500 calories per day if you’re currently eating 2,000.) One explanation is that when you cut calories, you lower metabolic rate. This leads to fewer free radicals, which are formed during normal food metabolism but which damage DNA. And, in fact, one study of 48 overweight adults published in the Journal of the American Medical Association showed that after six months of calorie restriction (via diet or diet plus exercise), people registered lower levels of DNA damage. Still, some experts say that even if calorie restriction does work, the gains will be relatively modest. It’s likely to extend your lifespan but only by 3 to 5 percent, says UCLA evolutionary biologist John Phelan, who has conducted research on calorie restriction. “So after a decade of depriving yourself, you might get a couple of extra years.” We recommend meeting—just not exceeding—your calorie needs by eating a variety of nutrient-packed foods like fruits and vegetables, whole grains and lean proteins.

Some studies suggest that folate—a B vitamin found in beans, citrus fruits and vegetables (particularly leafy greens)—may help protect against Alzheimer’s disease, colorectal cancer and strokes. However, some research indicates that folic-acid fortification may be a problem for older people. Why? Large doses of folic acid, the supplemental form of folate, may mask the early symptoms that warn of B12 deficiency—a problem that’s more common after age 55. Left undetected and thus untreated, B12 deficiency can lead to irreversible nerve and brain damage. Get folate/folic acids from foods like vegetables, fruits and beans. Just 1⁄2 cup of pinto beans or 1 cup of orange juice or romaine lettuce supplies about one-fifth of the daily requirement. If you’re over 55, it’s OK to take a basic multivitamin, but don’t take a specific folic-acid supplement. You’re unlikely to need it and it may be harmful.

Age-related macular degeneration (AMD), a condition characterized by the deterioration of the central retina, or macula, is the leading cause of blindness in people over 50. Studies show that vitamins C and E and zinc, as well as lutein and zeaxanthin—two antioxidants found in yellow and leafy green vegetables and in egg yolks—may help protect against and/or slow the progression of this condition. Furthermore, one Australian study links a high intake of vegetables—any kind—with a lower risk for AMD. While these findings are still preliminary, they underscore the benefits of loading your plate with nutrient-packed foods like vegetables, fruits, nuts—which provide significant amounts of zinc and some vitamin E in a 1-ounce serving—and, yes, even whole eggs. (Studies indicate that whole eggs, if you stick to not more than one per day, can fit into a heart-healthy diet.)