Selenium Health and Side effectsSelenium is a trace mineral required in small amounts for various metabolic pathways. Selenium is found in some foods, soil and water. Selenium content in food largely depends on the selenium content in soil where animals are raised and plants are grown. Dietary source of selenium includes wheat germ, grains, brewer’s yeast, butter, garlic, onion, sunflower seeds, walnuts, Brazil nuts, raisins, shell fish, salt-water and fresh-water fish, liver, kidney, medicinal mushrooms, ginseng, alfalfa, fennel seeds and catnip.
Selenium deficiency can occur in people in areas where the selenium content in soil is low, patients on total parenteral nutrition for their sole source of nutrition, and people with some gastrointestinal disorders where selenium absorption may be decreased.
Processing or refining methods may destroy the selenium in foods.
Health and selenium
- Selenium posses antioxidant properties and is a component of glutathione peroxidase.
- Prophylactic administration of sodium selenite in Keshan disease (cardiomyopathy) may help decrease the incidence of this disorder.
- Selenium supplementation may decrease the risk of developing prostate cancer in men, improve asthma symptoms, increase the rate of burn wound healing, may affect the development of cataracts, cystic fibrosis, HIV (especially during antiretroviral therapy), dandruff, several types of infections, decrease symptoms of intracranial pressure, liver disorders, male infertility and sperm motility, low birth weight infants, decrease lymphedema, myotonic dystrophy, pre-eclampsia, sepsis, rheumatoid arthritis, skin disorders, sunburn prevention, Grave’s disease, tinea capitis infection, mood elevation and quality of life.
- Low serum or tissue selenium levels are related to risk factor for some cancers, especially prostate cancer. However its efficacy in treatment of other cancer is not yet proven.
- These health benefits are based on unclear scientific researches, for better safety and effectiveness of this mineral more scientific researches are required.
Side effects and selenium
- High doses (4-5 times than normal intake) can lead to selenium toxicity and may cause abdominal pain, nausea, vomiting, diarrhea, metallic taste, weakness, fatigue, irritability, muscle tenderness, peripheral neuropathy, dermatological changes, liver, kidney, thyroid dysfunction, reduced sperm mortality or growth retardation.
- Low selenium levels are associated with kidney failure; kidney transplant can correct the levels. Low selenium levels are also associated with cardiomyopathy.
- Selenium intake from common foods is considered safe in pregnancy, lactation and for children, however high levels that cause toxicity should be avoided.
- Selenium levels may be reduced in women on oral contraceptives.
Selenium supplementation should be taken in recommended doses under the guidance of a health care professional. Selenium that is normally found in food when consumed is generally safe with no noted side effects.