If your body had a slogan, it would probably be something like "Divide and copy." That’s because every day, cells split and replicate, over and over again. But we all make mistakes—even at the cellular level. Once in a million or so divisions, something goes wrong, and the mistake produces an abnormal cell. Normally, the immune system corrects these mistakes. When abnormal cells go unnoticed and uncorrected, cancer becomes a possibility.
Just like normal cells, damaged cells will copy themselves, reproducing the mistake in every generation. As more and more cancerous cells pile up, a tumor begins to grow.
Preventing mistakes in the first place can help stop cancer from occurring. To do that, oxidative damage—the prelude to cell mutation—must be kept to a minimum. That’s where antioxidant vitamins and minerals come in.
Even when cancerous cells do appear, our bodies almost always dispatch them without a hitch. Certain nutritional supplements can help support your ability to squelch cancer before it grows out of control or even to inhibit early tumor growth.
Get an Edge with Antioxidant Vitamins
Researchers speculate that up to 30 percent of cancers are affected simply by what we eat. One study, for example, indicates that people who eat meat nearly every day have more than double the risk of colon cancer of those who eat meat about once a week. Plus, researchers have noted that people who favor vegetables, grains, and fruits have less risk of cancer than those who eat fewer of these plant foods.
Why is there such a strong connection between certain foods and reduced risk of cancer? For one thing, a steady diet of red meat and fatty foods brings an excess of free radicals into the body. These free-roaming, unstable molecules can damage cells and make them more susceptible to cancer.
| The Goodness of Green Tea Some people think that green tea—a favorite of the Japanese—is an acquired taste. If so, there’s a good reason to acquire it. The traditional pale-green brew that accompanies Japanese food appears to have potent anti-cancer properties, according to Jerzy Jankun, M.D., a cancer researcher and associate professor in the department of urology at the Medical College of Ohio in Toledo. Green tea contains a substance called epigallocathechin-3 gallate (EGCG). Dr. Jankun’s research shows that EGCG inhibits urokinase, the enzyme that allows tumors to grow and spread. “By inhibiting urokinase, those processes could be stopped,” says Dr. Jankun. “EGCG has been known to possess other anti-cancer activity, but inhibition of urokinase seems to be the most important factor.” How much green tea should you sip? You can follow the lead from the East: Asian tea lovers commonly drink up to 10 cups a day. While this may seem like a lot, research suggests that consuming such a large quantity may be necessary to reap green tea’s anti-cancer benefits. Regular green tea contains caffeine. Although it has only about one-third as much as the same amount of black tea, regular consumption might give you more caffeine than you want. Fortunately, you can find decaffeinated varieties in some supermarkets and health food stores—and the decaf kinds have equivalent amounts of EGCG. If you prefer your protection in capsules rather than cups, green tea extract is available in supplement form, says Dr. Jankun. Sometimes an equivalent in cups will be noted on the label, or the label will give the concen tration of green tea in milligrams. Since potencies are different, follow the directions on the label. Most brands advise taking one or two capsules two or three times a day. Just don’t go overboard when supplementing with green tea capsules. The potential dangers of taking excessive amounts of green tea in a purified form are still unknown, according to Dr. Jankun. |
Eating plenty of vegetables and fruits actually supplies the body with an armory of antioxidants—protective substances that can help destroy free radicals and protect fragile structures inside your cells from the damage that may lead to cancer.
Getting the requisite five or more servings a day of fruits and vegetables is the first step in defending yourself against cancer. While prevention may start on your plate, though, you can go even farther with specific antioxidant supplements known for their anti-cancer actions, says Keith Berndtson, M.D., medical director of the American Wholehealth Centers of Integrative Medicine in Chicago. In addition to a healthy diet, he says, "I’d stick to a high-potency multiple vitamin with additional antioxidants for cancer prevention."
Two of the most important antioxidants are also the most well known—vitamin E and vitamin C. These two are favorites when it comes to improving overall health, and for cancer prevention, they seem to be all-stars.
Oily vitamin E is hard to get in abundance from dietary sources alone. Supplemental amounts from 400 to 800 international units (IU) a day are recommended by W. John Diamond, M.D., medical director of the Triad Medical Center in Reno, Nevada, and co-author of An Alternative Medicine Definitive Guide to Cancer.
Water-soluble vitamin C is relatively easy to find in foods. Even though the Daily Value (DV) for C is only 60 milligrams, Dr. Diamond suggests much more for the prevention and treatment of cancer. He recommends between 1,000 and 8,000 milligrams in divided doses throughout the day.
Stop Cancers with Selenium
The essential trace mineral selenium has been connected with protection against cancer since the late 1960s. While we still aren’t sure how selenium works in the body, researchers continue to gather evidence that it seems to have anti-cancer effects.
Initially, researchers thought that selenium might help reduce the incidence of skin cancer. In a trial done by the Nutritional Prevention of Cancer Study Group at the Arizona Cancer Center in Tucson, researchers tried to determine whether the mineral helped prevent basal and squamous cell carcinoma, commonly known as skin cancer. The results were disappointing, but only when researchers focused on skin cancer. To their surprise, they learned that people getting selenium had significantly fewer prostate, colorectal, and lung cancers than people who weren’t getting the supplement.
| Toxins and Your Body The very word toxins seems to reek. Think of bootleg liquor and bad, cheap wine. Imagine jumbles of jumbo helpings of junk food, deep-fried in week-old oil. Picture bad clams slurping up wastewater from Pollution Bay. Or how about ominous-looking barrels of lead, cadmium, and mercury? Yes, these are all carriers of toxins. There’s another carrier, however, that you’re less likely to guess—you. Even in its best moments, your body is a toxin factory. You produce various chemicals that are considered toxins when you digest food, process hormones, or send a message via your nervous system. Moreover, the constant stream of toxins produced as a matter of course inside your body vastly outranks the number of toxins that enter it from the outside. Luckily, our bodies are usually able to handle the big job of getting rid of accumulated waste. “Contrary to what most people think, though, detoxification is not as simple as pooping and peeing,” says Sidney M. Baker, M.D., a physician in Weston, Connecticut, and author of Detoxification and Healing. It’s easier to understand the process of detoxification if you compare your body to a small city and think of detoxification as the city’s sanitation efforts, says Dr. Baker. In this city, a full 80 percent of the budget goes toward supporting sanitation by buying new garbage trucks. And these aren’t just any old garbage trucks—each one is specialized to pick up a certain kind of trash. In your body, that means that more than three-quarters of your daily energy expenditure goes toward creating specialized molecules (the garbage trucks) to usher various toxic molecules (trash) out of your body. In reality, detoxification is a process of building things rather than breaking them down. It’s more a process of synthesis than of trash-hauling, Dr. Baker points out. “It’s just like growing or healing.” In the body, transporting toxins follows fairly standard procedures. Some toxic molecules are safely moved to the intestines, liver, kidneys, or sweat glands for disposal. Others, like some metals, are sent to the hair or nails for long-term storage. After those toxins arrive, however, various things can happen—and some aren’t so good. If the toxin was made inside the body—such as a molecule of hormone—the “garbage truck” simply drops off the toxin and returns to circulation, seeking more toxins to dispatch. Trouble arises when an externally produced toxin—like a molecule of pesticide or heavy metal—is taken to the dump. The garbage truck founders at the dumpsite and gets stuck there, unable to return to service. After all, our trucks were designed before the days of strange toxins like petrochemicals. Our living systems don’t know quite what to do with them, Dr. Baker suspects. Cleaning up external toxins uses up more of the body’s resources. That’s why it’s smart to do your best to limit your exposure to external toxins. “Fresh, organically grown, unadulterated food is where we would all start from, ideally,” says Dr. Baker. He stresses, though, that a body that is fed even the purest diet still produces internal toxins that need to be cleaned up. Good nutrition is the most important support for your body’s detox abilities, says Dr. Baker. Be sure to get the Daily Value of all of the essential nutrients, he advises. That means eating a healthy diet as well as taking vitamin and mineral supplements. If you think you need extra help, turn to naturally detoxifying herbs like ginseng, garlic, or milk thistle, he says. |
Selenium supplements appear to encourage the death of potentially cancerous cells grown in laboratory dishes as well as inhibiting tumor growth. This leads researchers to predict that taking supplemental selenium may deliver cancer protection soon after you start taking it.
Selenium comes from the soil, and fruits and vegetables that come from selenium-rich soil are more likely to contain the mineral. Of course, there’s no way to know exactly whether you’re getting adequate selenium from the produce you buy in the supermarket. Supplements are the surest way to make sure that you get enough.
In the Tucson study, the people who showed increased resistance to cancer were taking more than 200 micrograms of selenium a day. According to Dr. Berndtson, this is a safe and effective amount to include in your anti-cancer supplement program. You should take amounts of selenium over 200 micrograms only under your doctor’s supervision.
| Can Isoflavones Protect You? You can find supplements of isoflavones, the plant estrogens found in soy and red clover, on the shelves of health food stores and even national drugstore chains. The isoflavone most likely to be in these supplements is genistein, and doctors are hopeful that this isolated substance, or other isoflavones from soy, will produce the same benefits that people get from soy-based diets, such as reducing the risk of breast and prostate cancer, heart disease, and osteoporosis. Genistein and other isoflavones appear to be promising substances, and “this is a very active area of research right now,” says Stephen Barnes, Ph.D., professor of pharmacology and toxicology at the University of Alabama at Birmingham. Some researchers, however, are doubtful that isoflavones such as genistein have the protective potential of soy proteins. Most studies have looked at soy proteins contained in foods such as tofu and tempeh rather than studying the benefits of isoflavones taken as supplements. There’s not enough evidence to confirm that isoflavones alone provide the same benefits as soy-based foods, according to some researchers. Most evidence of the potential benefits of isoflavones comes from Japanese populations that eat a traditional diet, including many soy-based foods. In these populations, the incidence of cancer, heart disease, and osteoporosis is lower than in the United States. The positive effects of soy, such as lowering cholesterol levels, seem to come from a combination of soy protein and isoflavones, Dr. Barnes says, and a supplement may not provide the same benefits. Isoflavones alone, however, do seem to improve artery elasticity, another component of circulatory health, he says. With regard to cancer, the focus has turned to genistein. Studies with laboratory animals suggest that this isoflavone may be useful in both protecting against and treating prostate cancer. Population studies focusing on cancer seem to be reassuring, since people who eat lots of soy foods are less likely to get cancer than people who eat a meat-based diet, Dr. Barnes says. Again, though, the same results might not occur with isoflavones. “It’s true that there are clinical questions that will take some time to answer,” Dr. Barnes says. In the meantime, if you want soy’s protective effects, you can eat 50 to 60 milligrams of isoflavones a day, he says. The amount of isofla vones in soy foods varies. A half-cup of tofu offers 35 milligrams, one cup of soy milk has 20 to 30 milligrams, and ¼ cup of dry soy protein granules provides 60 milligrams. If you do opt to take isoflavone supplements, it’s still prudent to stay within the 50- to 60-milligram range, Dr. Barnes suggests. “We think that’s safe because people have been getting that amount from foods,” he says. |
Fight Harder with Folic Acid
Many doctors recommend folic acid for women who are pregnant because it’s been shown that this B vitamin will reduce the risk of birth defects.
In food, folic acid comes in a form known as folate. This nutrient is essential. If it is in short supply, the body may produce abnormal cells, known as dysplasia, that can add up to cancer.
Among some other beneficial effects, folic acid seems to help prevent colon cancer. Studies indicate that men who don’t get enough have a greater risk of this type of cancer than men who do.
The Nurses’ Health Study at Harvard Medical School found that folic acid is good for women, too. In fact, the amount of folic acid found in many multivitamins was enough to cut women’s colon cancer rates by more than 75 percent.
In the study, researchers examined data for more than 120,000 female nurses who were selected in 1976 and reported their health status every two years thereafter. The longer the women took the vitamin containing folic acid, the smaller their risk of cancer became. "After 15 years of use, their risk was markedly lower," says Edward Giovannucci, M.D., Sc.D., lead researcher in the study and assistant professor of medicine at Harvard Medical School and Brigham and Women’s Hospital in Boston.
The nurses with the lowest incidence of colon cancer were getting at least the DV for folic acid—400 micrograms, an amount found in many multivitamins. There’s evidence, however, that we get the best anti-cancer benefits if we take more than the DV.
Taking a multivitamin that contains folic acid is a good policy, says Dr. Giovannucci. You can also enhance your daily diet with folate-rich foods. Among the best are broccoli, pinto and navy beans, chickpeas, spinach, sunflower seeds, and fortified breakfast cereals.
Include the Carotenoid Crew
Research has connected a group of substances called carotenoids with a reduced risk of cancer. In most of the studies, however, researchers studied the effects of carotenoid-rich foods rather than supplements.
Sometimes called carotenes, carotenoids are named for the vegetable that is one of the richest food sources—the lowly carrot. That’s not the only vegetable that contains this valuable nutrient, though. The giveaway is vivid color. Red vegetables like tomatoes, deep orange ones like squash, and dark leafy greens like kale also contain ample amounts of various types of carotenoids.
Of all the carotenoids that have been studied, however, beta-carotene is the most prominent. In initial studies, researchers found that the group of people who got the largest amount of this nutrient from foods also had substantially fewer cancers. Beta-carotene was hailed as the newest antioxidant vitamin, able to protect both the insides and outsides of cells against free radical damage.
When researchers started studying supplements of beta-carotene, however, they observed that the benefits didn’t apply to everyone who upped their consumption. For smokers, beta-carotene may have a negative effect. Two studies showed that smokers who got high doses in supplement form were actually more likely to develop lung cancer than smokers who took no beta-carotene.
These results have led experts to be wary of recommending supplemental beta-carotene to everyone. True, a nutrient that poses a risk to smokers may be beneficial rather than harmful to nonsmokers. Smokers are already at high risk for cancer, and perhaps because of that, they react differently to beta-carotene than nonsmokers. Researchers are wondering, though, whether it might be harmful to take beta-carotene in isolation from the rest of carotenoids, and with that question still hanging, a beta-carotene supplement can’t be recommended as an across-the-board preventive. The moderate doses of carotenoids that come from foods, however, continue to show substantial anti-cancer promise.
If you want to add to that diet, you might try a supplement called mixed carotenoids, says Dr. Berndtson. Look for one that supplies beta-carotene, gamma-carotene, lycopene, lutein, and zeaxanthin, he advises.
Addressing the Calcium Question
Not too long ago, calcium seemed poised to become a big anti-cancer supplement. Studies suggested that taking ample amounts of this bone-boon mineral could do more than keep your skeleton solid. In particular, precancerous polyps that can lead to colon cancer seemed to appear much less often in people who took more than the DV of calcium.
Then along came a study from Harvard Medical School, and some experts began to question whether high-dose calcium was really all that helpful in preventing cancer. Researchers examined the eating habits of nearly 48,000 men who were taking part in a six-year survey called the Health Professionals Follow-Up Study. They found that rates of prostate cancer went up when the men had more calcium in their diets. The increased cancer rates were especially prevalent among those who got more than 2,000 milligrams a day, according to Dr. Giovannucci, who was co-author of the study.
What causes the contradictory effects of calcium? It could be that another nutrient plays an opposing role, according to Robert E. C. Wildman, Ph.D., assistant professor of human nutrition at the University of Delaware in Newark. "It seems that greatly increased calcium intake may depress the active form of vitamin D," he says. According to Dr. Giovannucci’s study, vitamin D may play a role in preventing the uncontrolled cell growth that can lead to prostate cancer.
So how do you safely resolve the calcium quandary? Premenopausal women and all men under 65 need a daily 1,000-milligram supplement. Women who are past menopause and not taking hormone replacement therapy and men who are over 65 need 1,500 milligrams daily. Don’t exceed these amounts unless your doctor deems it medically necessary, Dr. Wildman says.
The DV for vitamin D is 400 IU a day for everyone. Stay on the safe side, recommends Dr. Wildman, by being sure to get your share of this important nutrient. Look for a multivitamin supplement that supplies the DV, or take it as a separate supplement.
