Selenium is an essential micronutrient (i.e., a substance the body needs only in very small quantities). It is found in trace amounts in certain foods.
What does selenium do?
Selenium is also believed to be effective in preventing cataracts and numerous viral diseases.
Since the body does not synthesize selenium, we have to get it from food or supplements, if necessary.2
Recommended Dietary Allowances for Selenium
Source: Food and Nutrition Board, Institute of Medicine, Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids, 2000. Multi-Vitamin/Mineral Supplement Monograph, 0ct. 2007.
**Lacking sufficient scientific evidence, authorities have established adequate intake (AI) amounts rather than recommended dietary allowances (RDAs).
Adequate selenium intake is based on observed average intakes in North American babies in good health.
Selenium enters the food chain through plants that draw this mineral from the soil. Wheat cultivated in North America is a good source of selenium. In Canada all farm animals are given a selenium supplement in their feed (excluding producing dairy cows).
Food Sources for Selenium:
Because of their high fat content, Brazil nuts can easily go rancid so choose nuts still in their brown skin to reduce the risks of buying rancid nuts
Shell the nuts yourself or buy small quantities of shelled nuts from a store with fast stock turnover. You can store them in the freezer.
Source: Health Canada, Canadian Nutrient File, versions 2001b and 2005; *U.S. Department of Agriculture (USDA), National Nutrient Database for Standard Reference.
Generally, selenium deficiency occurs only in the following cases:
Very minor deficiency may be associated with a variety of illnesses such as heart or inflammatory diseases, asthma, weakened immune system, cancer, cataracts, etc.
Exact selenium needs for seniors are not well known, and the current recommended dietary allowances are derived from those established for young adults. It is critical that seniors ensure that they are getting enough selenium in their diet because it is suspected that a selenium deficiency may increase the risk of anemia.
Signs of selenium deficiency:
Canadian and U.S. authorities have established the tolerable upper intake level of selenium at 400 µg a day for adults. Doses of 1,000 µg a day are considered toxic.
Signs of excess selenium:
*If you are pregnant or breastfeeding, selenium supplements are not recommended. Selenium intake from food is sufficient.
Natural health products or vitamin supplements:
1If you take a selenium supplement, take it either one hour before or two hours after taking these medications.
2Speak with your pharmacist if you plan to take selenium supplements. Your pharmacist can help you choose the solution that’s best for you based on your health and any drugs you take.