Tea/green tea

Studies show that green tea—infused with the antioxidant EGCG—reduces the risk of most types of cancer. "The phytonutrients in tea also support the growth of intestinal bacteria," says Bowerman.

"Specifically, they inhibit the growth of bad bacteria—E. coli, Clostridium, Salmonella—and leave the beneficial bacteria untouched." Why is this important? "Because up to 70 percent of your immune system is located in your digestive tract," says Susan Bowerman, assistant director of the Center for Human Nutrition at the University of California at Los Angeles. "Four cups a day will keep it functioning at its peak."

Chili peppers

"Chilis stimulate the metabolism, act as a natural blood thinner, and help release endorphins," says Gunnar Petersen, certified strength and conditioning specialist and a celebrity trainer. Plus, they're a great way to add flavor to food without increasing fat or calorie content. Chilis are also rich in beta-carotene, which turns into vitamin A in the blood and fights infections, as well as capsaicin, which inhibits neuropeptides (chemicals that cause inflammation). A recent study in the journal Cancer Research found that hot peppers even have anti-prostate-cancer properties. All this from half a chili pepper (or one tablespoon of chili flakes) every day.

Ginger

Contrary to popular belief, ginger—a piquant addition to so many Asian dishes—isn't a root, it's a stem, which means it contains living compounds that improve your health. Chief among them is gingerol, a cancer suppressor that studies have shown to be particularly effective against that of the colon. Chop ginger or grind it fresh and add it to soy-marinated fish or chicken as often as you can. The more you can handle, the better.

Blueberries

"This potent little fruit can help prevent a range of diseases from cancer to heart disease," says Ryan Andrews, the director of research at Precision Nutrition, in Toronto, Canada. One serving (3.5 ounces) contains more antioxidants than any other fruit. Drizzle with lemon juice and mix with strawberries for a disease-fighting supersnack.

Cinnamon

Known for making desserts sweet and Indian food complex, cinnamon is rich in antioxidants that inhibit blood clotting and bacterial growth (including the bad-breath variety). "Studies also suggest that it may help stabilize blood sugar, reducing the risk of type 2 diabetes," says dietitian Nancy Clark, author of Nancy Clark's Sports Nutrition Guidebook (Human Kinetics, 1996). "What's more, it may help reduce bad cholesterol. Try half a teaspoon a day in yogurt or oatmeal."

Sweet potatoes

Often confused with yams, this tuber is one of the healthiest foods on the planet. In addition to countering the effects of secondhand smoke and preventing diabetes, sweet potatoes contain glutathione, an antioxidant that can enhance nutrient metabolism and immune-system health, as well as protect against Alzheimer's, Parkinson's, liver disease, cystic fibrosis, HIV, cancer, heart attack and stroke. "One sweet potato a day is a great alternative to the traditional variety," says Clark.

Tomatoes

"I think of tomatoes as the 'fighting herpes helper' for the divorcé crowd," says Petersen. Their lycopene content can also help protect against degenerative diseases. "Cooked tomatoes and tomato paste work best," he says. Shoot for half a tomato, or 12 to 20 ounces of tomato juice, a day.

Figs

Packed with potassium, manganese, and antioxidants, this fruit also helps support proper pH levels in the body, making it more difficult for pathogens to invade, says Petersen. Plus, the fiber in figs can lower insulin and blood-sugar levels, reducing the risk of diabetes and metabolic syndrome. Select figs with dark skins (they contain more nutrients) and eat them alone or add them to trail mix. Newman's Own Fig Newmans are also a quick and easy way to boost the immune system. Aim for four figs per week.   Mushrooms (reiki, shiitake, maitake)

Delicious when added to brown rice or quinoa, these mushrooms are rich in the antioxidant ergothioneine, which protects cells from abnormal growth and replication. "In short, they reduce the risk of cancer," says Bowerman, who recommends half a cup once or twice a week. "Cooking them in red wine, which contains the antioxidant resveratrol, magnifies their immunity-boosting power."

Pomegranates

The juice from the biblical fruit of many seeds can reduce your risk of most cancers, thanks to polyphenols called ellagitannins, which give the fruit its color. In fact, a recent study at UCLA found that pomegranate juice slows the growth of prostate cancer cells by a factor of six. "Drink a cup a day," says Bowerman.