Selenium though toxic in large doses, is an essential trace mineral and is essential for most living organism. Like Iodine it is also important for proper functioning of thyroid gland.
It is a part of certain rare amino acids like selenocysteine and selenomethionine. It acts as cofactor for many anti-oxidant enzymes.
Selenium – Dietary Sources
Brazil nuts, mustard, mushrooms, barley, cheese, garlic, tofu, seeds and brown rice are very good sources of Selenium. The amount of selenium present in these sources also depend on the soil in which these are cultivated.
Biological Functions of Selenium
The important biological functions of Selenium are:
- Active interaction with other nutrients, such as iodine and vitamin E
- Studies have proved that it prevents certain kinds of cancer
- It is important in proper functioning of thyroid gland and related glands
- It prevents various diseases and improves overall immunity
Selenium – Deficiency
It is rare in most humans. Only countries where the soil is highly deficient of selenium this occurs. This deficiency is also associated with higher coinsurance of AIDS, TB and few other diseases. For instance, in the sub Saharan Africa where the selenium levels are very low in the soil the AIDS affected peoples’ percentage is high. In Senegal (also in sub Saharan Africa) the soil is rich in this mineral so the incidence of AIDS is less. This deficiency is also associated with Vitamin E deficiency.
Selenium – Requirements and supplements
The daily requirement of this mineral for an adult is 55 µg/day. Selenium is highly toxic if consumed more than the required amount. When the limit crosses 400 µg/day all the harmful effects will start to manifest, so one should be very careful about taking supplements for this mineral. A healthy food with whole grain cereals should give sufficient amounts of this mineral.