Karen Collins, MS, RD, CDN American Institute for Cancer Research
Weekly column for the week of April 03, 2006
Q: Is it true that green tea can help prevent prostate cancer?
A: More research involving large numbers of men is needed to confirm the apparent benefits of green tea in regard to prostate cancer, but the theory that green tea does protect against this disease has attracted a lot of scientific attention. Natural phytochemicals in green tea seem to increase the activity of enzymes that deactivate carcinogens, which could otherwise begin the process of cancer development. Laboratory research suggests that green tea's polyphenol phytochemicals can block prostate cancer tumors from growing larger and spreading even promoting prostate cancer cell self-destruction. Prostate cancer is unique because it can occur in a dormant, non-threatening form as well as a more aggressive, deadly form. One of the goals of the large human studies that are needed would be to more closely estimate the amount of green tea needed to lower the risk of prostate cancer. So far, studies suggest that the range could be from three to six cups a day. It would be a mistake for men, however, to rely on green tea alone to lower their risk. The best protection will almost surely come from the interaction of a variety of plant substances such as lycopene (abundant in tomatoes), selenium (in seafood, whole grains and vegetables) and indole-3-carbinol (in cruciferous vegetables like broccoli). In other words, men should follow a balanced, mostly plant-based eating style like the New American Plate, which is advocated by the American Institute for Cancer Research. Men should also practice weight control, which studies show is protective.
Q: Will 100-calorie packages of cookies and crackers help me control my snacking?
A: Mini-packages of snack foods offer several advantages. First, the small size of these snacks effectively limits your portion. Second, 100 calories is low enough to be a suitable snack for almost anyone. Third, the usually smaller-sized pieces make you feel like you're getting more. Fourth, the packages are easily portable and storable, so you never have to turn to a vending machine for a choice much higher in calories. However, the ability of these small packs of refined carbohydrates, sugar and fat to satisfy your hunger and fuel you may be short-lived. For more sustained energy and hunger control, you should look for snacks that provide protein, fiber, or both. Choices near 100 calories that better meet this goal include a large apple, a medium banana or pear, a cup of applesauce or juice-packed canned fruit, 6 dried apricots, a quarter-cup of raisins, a piece of string cheese, or a 100-calorie container of yogurt. For many people, a snack with 200 calories may fit their needs better. For these people, a larger amount or combination of the above choices would be suitable. They could also have a quarter cup of nuts, which provides both protein and satisfying fiber.
Q: Does a food or supplement providing 100 percent of the Daily Value for calcium meet the needs of a woman over age 50?
A: The Daily Value (DV) for calcium used on food labels is 1,000 milligrams (mg). It covers the needs of most adults, but current federal dietary recommendations call for teenagers to get 1,300 mg and adults over age 50 to get 1,200 mg. Generally, a well-balanced diet supplies about 300 mg of calcium from small amounts in a variety of foods, in addition to the calcium from dairy products. If you eat foods or take a supplement providing 100 percent of the DV 1,000 mg your total intake should be about 1,300 mg to meet the recommendations. However, studies show that when we consume more than 500 mg of calcium at a time, it is not absorbed efficiently. To ensure you are getting a full supply of calcium, it's preferable to have the bulk of your calcium come from two or more different foods or supplements at different times during the day.
Reprinted with permission from the American Institute for Cancer Research
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