Research report

Vegetables that prevent disease

Research shows that certain vegetables contain more health-enhancing active chemicals than others. It makes sense to include more of these superfoods in your diet. Here we outline the foods to pile up on your plate.

Leafy greens

Health advantage Help prevent type 2 diabetes. Lower the risk for heart disease and possibly cancer.

Maximize the benefits Have a small amount of fat with your greens—such as olive or canola oil, chopped nuts, or slices of avocado—to increase the absorption of nutrients.

Research report Enjoying leafy greens more often—as a crunchy salad, a crisp stir-fry, a side dish of sautéed spinach or Asian greens, or by tossing strongly flavored green kale or watercress into soups, stews, and casseroles—could lower your risk for type 2 diabetes by 14 percent. No other single vegetable family has this power to help keep your blood glucose in the healthy zone, say scientists from the diabetes research team at the University of Leicester in the UK.

What’s so special about greens? Plenty. These versatile vegetables contain beta-carotene, vitamin C, and polyphenols, all of which support your body’s antioxidant defenses and fight against the damage that triggers diabetes. Greens also contain the mineral magnesium, which helps your body process blood glucose in a healthy way. Surprisingly, greens have a small amount of good fats, which help make your cell walls responsive to the blood glucose–controlling hormone insulin. But that’s not all. Getting your greens can also help with weight control because most of them have 40 calories or less per cup.

Greens are good for your whole body. Every additional daily serving that you add to your diet could lower your risk for heart disease by as much as 23 percent, say researchers at the Harvard School of Public Health. Why? All the benefits listed above, plus more: greens also provide vitamin C and fiber, which can help lower cholesterol and control body weight. Cell-protecting compounds in greens may be the reason these goodies could help lower your risk for cancers of the mouth, throat, larynx, esophagus and stomach, according to the American Institute for Cancer Research.

Pumpkin Winter squash

Health advantage Reduces risk for cancer, heart disease, diabetes, and vision loss.

Maximize the benefits Having just a teaspoon (3–5 grams) of vegetable oil with a serving of squash will help your body absorb more of the vegetable’s fat-soluble beta-carotene.

Research report Bursting with vitamin C, colorful and tasty squash is a top source of the disease-fighting carotenoids alpha-carotene and beta-carotene. These compounds protect against cancer and lower your risk for heart disease, diabetes, vision problems, and more. Your body uses carotenoids as antioxidants to neutralize cell-damaging oxygen molecules called free radicals. It also converts carotenoids into vitamin A, which bolsters immunity.

Diets that are high in beta-carotene are associated with low cancer risk. Getting this compound from food—not from pills—is crucial; research suggests that beta-carotene supplements do not protect against heart disease and cancer and may even increase the risk of cancer in people who smoke.

While squash is low in fat, it does deliver a respectable 340 milligrams of alpha-linolenic acid (ALA), a good-for-you omega-3 fatty acid. This plant-based fat is emerging as a health hero. Getting 1 gram per day lowers heart attack risk by 60 percent. Getting about 3 ¹/₂ grams per day could reduce levels of heart-threatening LDL cholesterol by 7 to 13 percent. While flax seeds and walnuts are richer sources of ALA, adding squash to your diet can help.

A bonus: Squash also contains polysaccharides that help regulate blood glucose. And this family of vegetables is a great source of lutein and zeaxanthin—carotenoids that accumulate in the retina of your eyes, where they act as sunglasses, filtering out damaging ultraviolet rays and so protecting against cataracts and age-related macular degeneration.

Eat these seeds!

Don’t throw away the seeds that you’ll find at the center of a whole winter squash. They’re rich in zinc—a mineral that supports wound healing—and manganese, which helps antioxidants protect body tissues. To eat the seeds, first remove the strings attached to them, then rinse and dry the seeds. Spread on a baking sheet and roast in the oven at 180°C (350°F), stirring occasionally, for 20–30 minutes. Cool. You can shell the seeds or remove the shells as you eat them.

Tomatoes

Health advantage Protect against cancers of the lung, stomach, and prostate. Keep your heart, arteries, and bones healthy. Cut the risk of stroke. May also lower the risk of cancers of the cervix, breast, mouth, pancreas, esophagus, colon, and rectum.

Maximize the benefits Enjoy cooked tomato products, such as tomato soup or sauces, several times a week. One cup (125 ml) of cooked tomato puree delivers 12 times more of the cancer-fighting antioxidant lycopene than a cup of chopped fresh tomatoes.

Research report In one Harvard School of Public Health study that followed 47,000 men for 12 years, those who ate tomato products two or more times a week were 25 percent less likely to develop prostate cancer and 34 percent less likely to develop aggressive prostate cancer than men with the lowest intakes.

Lycopene may also discourage the proliferation of cancers of the breast, lungs, and endometrium (lining of the uterus), according to the American Institute for Cancer Research. But skip supplements. Experts suspect lycopene works in concert with other nutrients found in food. Studies of pills and capsules containing lycopene on its own have found few, if any, benefits.

More reasons to love tomatoes: Recent research suggests that they may bolster bone health and help reduce levels of heart-menacing LDL cholesterol.

Brassicas Cruciferous vegetables

Health advantage May help reduce the risk for cancers of the colon, rectum, mouth, oesophagus, stomach and lungs.

Maximize the benefits Steaming, microwaving, or stir-frying brassicas (rather than boiling them) retains more health-protecting glucosinolates, folate, and vitamin C. Steaming also enhances the ability of the fiber in broccoli to whisk cholesterol-rich bile acids out of your digestive system, helping to keep levels of heart-threatening LDL cholesterol low.

Research report Researchers at Johns Hopkins University made a breakthrough discovery back in 1992: sulforaphane, isolated from broccoli, slowed the growth of cancer cells in test tube studies. Since then, scientists have discovered additional cancer-fighting phytochemicals in broccoli and the other brassicas. These include carotenoids, coumarins, dithiolethiones, flavonoids, glucosinolates, and isothiocyanates. One way in which they help is by switching on genes that soothe inflammation and help protect cells from cancer-causing damage.

Some studies suggest that people who eat lots of brassicas have lower risk for lung, colorectal, stomach, breast, and prostate cancers. Researchers at Florida A&M University are investigating a brassica compound called C-substituted diindolylmethane as a potential treatment for triple-negative breast cancer. This fast-growing cancer accounts for 15 to 20 percent of all breast cancers. But not everyone responds to the beneficial substances in broccoli, cabbage, brussels sprouts, and other members of this diverse vegetable family. About 50 percent of us lack a gene that helps the body retain and use these compounds. Right now there’s no test to see if you’re a brassica-responder, but even so, these high-fiber, low-calorie, vitamin-rich vegetables are still worth eating regularly.

Chili peppers

Health advantage Capsaicin-containing creams and ointments can help ease the pain of osteoarthritis, rheumatoid arthritis, diabetic neuropathy, post-herpetic neuropathy, and possibly nerve pain related to HIV/AIDS.

Maximize the benefits Be patient. It may take several weeks for over-the-counter capsaicin creams to effectively ease aches and pains.

Research report Chilies have a long history as a home remedy for pain. In 1979 a new era began when researchers discovered that capsaicin—the ingredient that gives chilies their heat and zing—has a unique talent: it can deplete a chemical messenger in nerve cells that carries pain signals to the brain.

In one study at Case Western Reserve University, 101 people with osteoarthritis or rheumatoid arthritis had their pain reduced by up to 57 percent after four weeks of applying capsaicin cream daily. When a group of 252 people with diabetes-related nerve pain (diabetic neuropathy) used capsaicin cream or a placebo for eight weeks in another study, the capsaicin users reported a 58 percent improvement in pain relief.

Latest breakthrough: A prescription-only capsaicin patch is showing promise against tough-to-treat pain associated with HIV/AIDS and with shingles infections.

Legumes

Health advantage May help reduce the risk for heart disease, high blood pressure, and high cholesterol. Can help keep blood glucose at optimal levels.

Maximize the benefits Minimizing the gassy aftereffects of beans could help you eat more of these healthful vegetables. Types that produce less gas include azuki and mung beans, lentils, and black-eyed, pigeon, and split peas. Soaking legumes overnight before cooking, then chewing them thoroughly, also helps break down gas-producing sugar molecules called oligosaccharides.

Research report Forget those flatulence jokes. Fitting in four quarter-cup (47-gram) servings of dried beans or peas a week could reduce your risk of coronary artery disease by as much as 21 percent, say researchers from Tulane University. And when people with type 2 diabetes ate a cup (190 grams) of beans every day for 12 weeks in a University of Toronto study, their blood glucose control improved significantly.

Beans are a great source of soluble fiber, which helps lower cholesterol levels by whisking cholesterol-rich bile acids out of the body in bowel movements. This fiber also helps keep blood glucose lower and steady.

Sweet potatoes

Health advantage Can help control blood glucose.

Maximize the benefits In any recipe where you would use white potatoes, you can use antioxidant-rich sweet potatoes instead.

Research report Compared with white potatoes, sweet potatoes have a higher fiber content and a lower glycemic load. In addition there are compounds in sweet potatoes that may help people with type 2 diabetes better control their blood glucose. In a study conducted at the Medical University of Vienna, people with diabetes who received a sweet potato extract increased their blood levels of adiponectin, a hormone that plays a role in the way the body uses insulin. Their blood glucose levels also improved.

Whether white, purple, or orange, sweet potatoes are a good source of fiber and vitamin C as well as antioxidants such as beta-carotene and anthocyanins, which may protect against inflammation, heart disease, and cancer.

Vegetables are naturally good and contain vitamins, minerals, and phytochemicals that not only help keep you healthy but also help protect against some diseases.