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Please Pass the PreventionSome foods that may act as “medicine”
There’s increasing scientific evidence that what you eat every day can help prevent heart disease, cancer, and other ills.
Consider lutein, a yellow pigment found in dark green leafy vegetables and egg yolks. A recent study suggests lutein may help prevent clogging of neck arteries that can lead to stroke; other research suggests lutein can also help prevent macular degeneration, the most common cause of blindness in older people. Studies are also piling up on the benefits of chemicals called flavonoids in tea (especially green tea), which may reduce the risk of coronary heart disease, as well as cancer—including lung, skin, stomach, pancreas, colorectal, bladder, and mouth cancers.
“One in every 2.5 million Americans at some point in their lives, are going to hear the words ‘you have cancer.’ While there are generic and environmental factors that cause cancer, a lot of people are not getting enough of the nutrients that nourish the immune system and help other mechanisms that fight cancer,“ remarks Mitchell Gaynor, MD, medical director of the Center for Complementary and Integrative Medicine at New York Weill Cornell Medical Center. “So it is critically important for people to be pro-active about nutrition.”
Prevention on the menu
Cancer is a step-wise process that takes place over decades. It can start with pro-carcinogens, substances that are converted into cancer-causing chemicals. “If a carcinogen enters the body and is not detoxified, it can cause problems with DNA, the blueprint for cellular division. Carcinogens can cause mutations in DNA, DNA repair mechanisms can be lost, and tumor suppressor genes can be disabled,” says Dr. Gaynor.
“We know exactly where many carcinogens target our DNA, and what deficits happen. The good news is that at each of these steps, phytonutrients, or plant-based chemicals, can influence the chances of that step leading to cancer.”
Some phytonutrients increase enzymes that help get rid of carcinogens or hamper chemicals that promote cancer. For example, resveratrol, a compound in red grapes, can inhibit a chemical called cyclooxygenase-2 (COX-2), which not only makes carcinogens more active in the body, but also helps cancer cells grow new blood vessels to nourish growth, and keeps them from normal “programmed cell death,” explains Dr. Gaynor. “There are other nutrients, from omega-3 fatty acids to garlic to green tea, that can increase detoxifying enzymes.”
Omega-3 fatty acids are also thought to help prevent blood clotting, prevent hardening of the arteries, and maintain normal heart rhythms. Garlic has been touted for its cholesterol-lowering effects. Resveratrol is also a potent anti-oxidant that helps combat oxidation of LDL cholesterol, a process that helps it enter artery walls.
Soy powerful
Compounds called isoflavones contained in soy may help lower cholesterol, build bone mass, and possibly even prevent the accumulation of brain plaques that lead to Alzheimer’s disease, according to a number of recent reports. Soy isoflavones may also have potent effects against breast cancer.
“There are two major types of estrogen metabolites. There’s 16-hydroxyestrone, which is more active and causes breast cell proliferation, and 2-hydroxyestrone, which is protective against breast cancer. Most of the estrogen in women’s bodies is the 16-hydroxy form. Studies have shown that soy can shift the type of estrogen in a woman’s body from the type that predisposes to breast cancer to the type that actually protects against breast cancer,” says Dr. Gaynor. “While soy is a phytoestrogen, and has estrogenic effects, it’s one-ten-thousandth as powerful as the body’s own natural estrogen.”
Other new research: A study among 478 postmenopausal Japanese women found that women who consume over 50 mg of soy a day have increased bone mass. A three-year animal study reported at the annual meeting of the American Chemical Society in April 2001, found that soy isoflavones reduced tau, a protein that contributes to brain plaques in Alzheimer’s disease. And, a Scientific Advisory from the American Heart Association says people with elevated total cholesterol could lower their cholesterol by eating 25 to 50 grams a day of soy protein containing isoflavones.
Venerable vegetables
There are a number of chemicals in cruciferous vegetables—broccoli, cauliflower, cabbage, and Brussels sprouts—that may protect against cancer. Among them: sulforaphane and indole-3 carbinol. “Sulforaphane is also a potent inducer of the detoxifying enzymes, called phase 1 and phase 2 enzymes,” says Dr. Gaynor.
Research at the Strang Cancer Prevention Center has shown that indole-3 carbinol can also change the metabolism of estrogen in the body from the harmful 16-hydroxy estrone to the less-harmful 2-hydroxy estrone. Indole-3 carbinol also also seems to increase phase 2 enzymes, observes Dr. Gaynor. Clinical trials testing an indole-3 carbinol supplement are now underway at Strang.
Researchers at Johns Hopkins have developed strains of broccoli and broccoli sprouts (three-day-old plants) that contain high levels of sulforaphane.
Vegetables and fruits also contain carotenoids, antioxidants that may combat cancer, heart disease, and other illnesses. In addition to lutein, there’s lycopene (in tomatoes), vitamin C (in citrus fruits), and beta carotene (found in yellow and orange vegetables), which all may have cancer-preventive effects, says Dr. Gaynor.
Never too late to change diet
Of course, there are no guarantees that changing your diet will automatically protect you from cancer or any other disease.
“The way these compounds work is multi-factorial, some may work together. Some may be better in their natural forms, while we may need supplements for other things, like selenium,” says Dr. Gaynor. But these are simple changes to make, and may add up to substantial benefits.
It’s also important to realize that both cancer and cardiovascular disease may take decades to develop, giving you a chance to head them off along the way. “People often say to me ‘I’m 55, 65, 75 years old, isn’t it too late for me?’ The answer is, it is never too late. You still have an immune system that needs the proper phytonutrients to function properly, and you still have a detoxification system which needs the proper nutrients,” stresses Dr. Gaynor.
This article originally appeared in the September 2001 issue of Food & Fitness Advisor.
