Nutrition Being Studied As Part of Prevention of Prostate Cancer

By Mary Kay Holloway

Science regarding nutrition and cancer prevention is a process of building a picture from previous information and can be very confusing. Prevention of prostate cancer with nutrition is being studied almost as much as prevention of breast cancer with nutrition.

Two nutrients, selenium and vitamin E, alone or in combination, are being studied by the National Cancer Institute. SELECT (Selenium and Vitamin E@01 Bold Type>Cancer Prevention Trial) is a randomized controlled trial that is studying the relationship of these nutrients and prostate cancer risk. To evaluate results, the trial will continue for seven years and will focus on supplement use to provide selenium and/or vitamin E. Researchers need to use supplements to keep consistent levels of these nutrients in the blood. But we can get these nutrients from whole foods as well.

Selenium and vitamin E are antioxidants. An antioxidant is a substance that reduces damage because of oxygen. In the cellular level, antioxidants may slow down the rate of aging of a cell by protecting it from too much oxygenation, much like protecting metal from rusting. The way that vitamin E and selenium work as antioxidants differ, which explains the reason for using these supplements both alone and together in the SELECT trial.

Selenium is an essential trace mineral for our bodies. Research in the past 35 years has shown evidence that selenium may play a role in cancer prevention, especially when levels of selenium in the blood are low. Selenium is available from certain foods, however the level in these sources is directly related to the level of selenium in the soil in regions throughout the world.

Deficiency of selenium in the United States is rare but low levels may exist in people with medical conditions that affect absorption of the nutrient or with diets that do not supply enough of the nutrient. According to the National Institutes of Health Office of Dietary Supplements, food sources of selenium are generally found in plant foods such as Brazil nuts, oatmeal, Swiss chard, rice, barley, whole wheat bread or in the meat of animals that may have eaten the plants. Many multiple vitamin and mineral supplements also contain selenium.

Vitamin E is a fat-soluble vitamin that exists in nature in different forms, each with its own function in our body. These functions range from being essential to human reproduction to protecting the cells against the oxygen damage mentioned above. This is especially seen in nerve cells. Deficiency of vitamin E, as with selenium, is rare but can be found in people with fat mal- absorption syndromes, cystic fibrosis, and some inherited disorders. Foods that provide vitamin E for our body include vegetable oils, nuts, green leafy vegetables and fortified cereals. Many multiple vitamin and mineral supplements also contain vitamin E.

Nutrition research still is a puzzle with many pieces contributing to the whole picture. The SELECT trial is another of these pieces looking at the effect of large amounts of nutrients on the development of prostate cancer. It will be five years or more before we will know the results of this study.

While we wait for the puzzle to be put together, we can look to the majority of research pieces which repeatedly show that not one food but a diet full of fruits, vegetables, whole grains, beans, and low-fat animal sources may have a positive relationship with reducing cancer risk. This lifestyle also should include exercise, or moving your body in any way, each day for about 30 minutes. After all, there hasn’t been any research yet that has shown these lifestyle habits to be harmful.

Mary Kay Holloway is the registered dietitian at the Community Cancer Center, Normal.

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