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Epidemiological studies show us that people who eat more antioxidants have a lower risk of cancer. It is estimated that 30 to 40 percent of all cancers can be prevented by lifestyle and dietary measures alone.

Let me introduce you to two of our most valuable antioxidant minerals: zinc and selenium.

Zooming in on Zinc

Zinc is present in almost every cell in our bodies and is a component of about 200 enzymes. In fact, it functions in more enzymatic reactions than any other mineral. Zinc plays a critical role in the immune system where it helps regulate the production and activity of T lymphocytes (white blood cells that help fight infection) and natural killer cells (cells that battle cancer).

Unzipping Zinc’s Secrets

Scientists have known for decades that zinc may play an important role in prostate health, but just exactly what that role is remains elusive. The prostate gland contains the highest concentration of zinc in the body, and clinical evidence indicates that cancerous prostate cells contain less zinc than healthy prostate cells.

While there is no specific disease associated with zinc deficiency, a diet lacking in zinc can lead to problems such as frequent infections, delayed wound healing, decreased appetite, decreased sense of smell and taste, white flecks on the nails, poor skin conditions, and poor growth in children.

A diet of whole foods that includes good sources of zinc such as oysters, beef, yogourt, and pumpkin seeds is a recipe for healthy growth and immunity as well as a smart cancer prevention strategy.

Searching for Selenium

Required in very small amounts measured in micrograms (mcg), selenium is a powerful antioxidant. It is a vital part of the enzyme glutathione peroxidase that works closely with the antioxidant vitamins C and E to neutralize free radicals, the unstable, highly reactive molecules that can damage our cells and ultimately lead to cancer.

In the Nutritional Prevention of Cancer Trial of 1996, over 1,300 skin cancer patients received either 200 mcg of selenium per day or a placebo. After four and a half years of treatment, while there appeared to be no benefit from selenium with respect to skin cancer, the selenium group had 46 percent fewer lung cancers, 58 percent fewer colorectal cancers, 63 percent fewer prostate cancers, and 50 percent fewer cancer deaths in total compared to the placebo group.

Since then, many more studies have demonstrated the potential benefits of selenium supplementation in reducing the risk of colorectal, prostate, and lung cancers. It may also be a good candidate as a supportive element in the treatment of ovarian cancer in women receiving chemotherapy, and as a chemopreventive in women who carry a mutation in the BRCA1 gene. For maximum protection against cancer, studies indicate a daily intake as high as 100 to 300 mcg may be necessary.

Selenium deficiency is mostly due to the lack of this mineral in the soil. Good dietary intake of selenium comes from meats of animals raised on selenium-rich feed and grains grown in selenium-rich soils. Walnuts and especially Brazil nuts are also excellent sources.

More is Not Always Better

Excessive selenium intake of over 900 mcg per day taken over a prolonged period of time is toxic and can result in selenosis. The tolerable upper intake of 400 mcg per day for adults has been set by the National Academy of Sciences to prevent this toxicity.

All Together Now

Along with a diet rich in whole foods, nutritional supplements play an important role in preventing and treating all types of cancer. And although we have seen the value of supplementing with just zinc or selenium, mounting evidence confirms that a combination of antioxidants will provide greater protection against cancer than any single nutritional antioxidant. Just make sure selenium and zinc are a part of the mix for optimal cancer prevention.

Selenium: The Recommended Dietary Allowance (RDA) in Micrograms

Jill Hillhouse, RNCP, is a certified nutritional practitioner, health and lifestyle writer, and instructor at the Institute of Holistic Nutrition in Toronto, ON.

Source: alive #284, June 2006

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