HealthLink: Selenium may benefit people at risk of cancer, inflammatory and infectious diseases
A review published in the summer 2005 issue of the Canadian Journal of Dietetic Practice and Research indicates that selenium intakes above levels needed for basic immune function may benefit people at risk for certain diseases. Selenium is an essential trace mineral that acts as both an antioxidant and anti-inflammatory agent. It is involved in several key metabolic activities via selenoproteins - enzymes that protect against oxidative damage and regulate immune function. Intakes above recommended levels may be beneficial for people whose oxidative stress loads are high, such as those with inflammatory or infectious diseases like rheumatoid arthritis, human immunodeficiency virus/AIDS or those at high risk for cancers, particularly prostate cancer.
The new Recommended Dietary Allowance (RDA) for selenium is 55 µg daily for healthy adults. The Tolerable Upper Intake Level is set at 400 µg per day. Canadian intakes were in the range of 113 to 220 µg daily according to a report published in the 1970s. More recent data from the third US National Health and Nutrition Survey indicate that current US intakes average 106 µg per day. Despite the lack of standardized selenium intake data, the review suggests that a selenium deficiency would not be expected in the general Canadian population. However, subclinical deficiencies may occur in certain groups due to a combination of increased need and malnutrition.
There is growing evidence that selenium intakes above the RDA may help enhance immunity, protect against cancer and moderate infection and inflammation. For instance, several epidemiological studies have shown that people with the highest selenium levels have a reduced risk of cancer incidence and mortality. Selenium may also have an impact on viral disease progression and the production of inflammatory prostaglandins. Thus, modified nutrition recommendations may benefit some at-risk groups.
CONSUMER TIPS:
The most reliable dietary sources of selenium include meats, seafood, and milk products. Grain products, vegetables and fruit also contribute selenium, but their content depends on the soil they are grown in. A healthy eating pattern with adequate intakes of selenium-rich foods may promote optimal immunity and help to protect against certain diseases.
WANT TO LEARN MORE?
Refer to the review by Ryan-Harshman M and Aldoori W. The Relevance of Selenium to Immunity, Cancer and Infections/Inflammatory Diseases. Canadian Journal of Dietetic Practice and Research, 2005; 66(2):98-102.
HealthLink is an e-mail newsletter from the team of registered dietitians at the Beef Information Centre: a non-profit organization committed to provide credible and timely information. Please share it with colleagues.
Visit the Institute of Medicine report on
Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids
Subscribe to HealthLink.