Selenium
Selenium is an essential nonmetallic trace element. Selenium acts a s a defense against oxidative stress (free radicals). It also helps in the regulation and maintainence of thyroid activity. Selenium is also involved in cell synthesis and repair.
L-selenomethionine is an organic form of selenium found in
grains, meat, yeast, and certain
vegetables and has been used in
cancer prevention clinical trials. Studies suggest that
people with low selenium levels have a greater risk of developing or dying from cancer of the
bladder, breast, colon, rectum, lung, and prostate.
The body uses the nutrient selenium to make specific types of
antioxidant proteins, which protect against
cancer-causing free radicals.
What does the data show?
A five-to-nine-year safety and efficacy study tested whether selenized yeast, which is about 85 percent selenomethionine, could prevent nonmelanoma skin cancer. The study found that selenized yeast significantly reduced all cancer deaths and decreased rates of lung, prostate, and colorectal cancer.
According to the National Cancer Institute's Division of Cancer Prevention, an expert panel
determined that the content, stability, and purity of selenized yeast was too variable among
batches, and recommended that
l-selenomethionine be used in the large scale, multi-year
Selenium and Vitamin E Cancer Prevention Trial (SELECT). SELECT was launched in 2001 and is the
first study to look at the effects of selenium and vitamin E on the risk of prostate cancer, and to
find out if either or both agents prevent prostate cancer.
How much selenium does one need?
For both men and women age 19+, the Recommended Daily Allowance for selenium is 55 micrograms (µg) per day. Adult women who are lactating or pregnant have slightly higher RDAs, at 70 µg and 60 µg, respectively.
What are some good food sources of selenium?
- Three oz. light tuna, canned in oil (drained): 63 µg selenium (95% of Daily Value, D/V)
- Spaghetti with meat sauce (frozen entree): 34 µg
- Three oz. light meat (e.g., roasted turkey): 32 µg
- 3 1/2 oz roasted chicken breast: 20 µg
- One whole medium egg: 14 µg
- 1/2 cup 2% low-fat cottage cheese: 12 µg