As a vital component of the body's antioxidant defence system, selenium is a key player in thyroxine metabolism as well as an invaluable nutrient in reproductive health. Dietary intakes of selenium in the UK during the 70’s were nearly twice the level we consume today. Official data shows that the selenium intake for many adults in the UK is now below the RNI and this situation is due in part to the reduction in imports of selenium-rich wheat from North America.
Selenium has received a great deal of attention for its role in combating cancer. Cornell University and the University of Arizona conducted a 5 year study, which showed that the consumption of 200mcg of selenium daily resulted in:
- 63% fewer prostate tumours.
- 58% fewer colorectal cancers.
- 46% fewer lung malignancies.
- 39% overall decrease of cancer deaths.
In other studies, selenium showed promise in preventing cancers of the ovaries, cervix, rectum, bladder, oesophagus, pancreas and live, as well as leukaemia. Studies of cancer patients reveal that people with the lowest blood levels of selenium developed more tumours and had a higher rate of disease recurrence, a greater risk of cancer spreading and a shorter overall survival rate than those with high selenium levels. In addition, selenium can protect the heart, primarily by reducing the 'stickiness' of the blood and decreasing the risk of clotting, which in turn lowers the risk of heart attack and stroke.
Selenium increases the ratio of of HDL ('good') cholesterol to LDL ('bad') cholesterol, which is critical for healthy heart. Smokers and anyone who has already had a heart attack or stroke may gain the greatest cardiovascular benefits from selenium supplements, though everyone may profit from taking selenium in a daily vitamin and mineral supplement.