Benefits of Colloidal Selenium
Selenium may be of benefit relative to the following conditions:
- Colon cancer (reduces risk)
- Dermatitis herpetiformis
- Heart attack
- HIV support
- Immune function (for elderly people)
- Infections (to prevent hospital-acquired infections
- in very low birth weight infants)
- Infertility (male)
- Lung cancer (reduces risk)
- Pancreatic insufficiency
- Phenylketonuria (if deficient)
- Prostate cancer (reduces risk)
- Rheumatoid arthritis
- Cardiac arrhythmia
- Cardiomyopathy (only for Keshan’s cardiomyopathy)
- Childhood diseases
- Diabetic retinopathy (in combination with vitamin A, vitamin C and vitamin E)
- Down’s syndrome
- Halitosis (if gum disease)
- Hypothyroidism (if deficient)
- Liver cirrhosis
- Macular degeneration
- Osgood-Schlatter disease
- Pap smear (abnormal)
- Pre- and post-surgery health
- Retinopathy (combined with vitamin A, vitamin C and vitamin E)
What does it do?
Selenium activates an antioxidant enzyme called glutathione peroxidase, which may help protect the body from cancer. Yeast-derived forms of selenium have induced “apoptosis” (programmed cell death) in cancer cells in test tubes and in animals.1 2 3 A double-blind trial that included over 1,300 people found those given 200 mcg of yeast-based selenium per day for 4.5 years had a 50% drop in the cancer death rate compared with the placebo group.4 Another study found that men consuming the most dietary selenium (assessed indirectly by measuring toenail selenium levels) developed 65% fewer cases of advanced prostate cancer than did men with the lowest levels of selenium intake.5
Selenium is also essential for healthy immune functioning. Selenium supplementation has reduced the incidence of viral hepatitis in selenium-deficient populations, presumably by enhancing immune function.6 Even in a non-deficient population of elderly people, selenium supplementation has been found to stimulate the activity of white blood cellsprimary components of the immune system.7 Selenium is also needed to activate thyroid hormones.
In a double-blind trial, selenium supplementation of infertile men improved the motility of sperm cells and increased the chance of conception.8
Where is it found?
Brazil nuts are the best source of selenium. Yeast, whole grains, and seafood are also good sources. Animal studies have found that selenium from yeast is better absorbed than selenium in the form of selenite.9
Who is likely to be deficient?
While most people probably don’t take in enough selenium, gross deficiencies are rare in Western countries. Soils in some areas are selenium-deficient and people who eat foods grown primarily on selenium-poor soils are at risk for deficiency. People with AIDS have been reported to be depleted in selenium.10 Similarly, limited research has reported an association between heart disease and depleted levels of selenium.11 People who are deficient in selenium have an increased risk of developing certain types of rheumatoid arthritis.12
How much is usually taken?
While the Recommended Dietary Allowance for most adults is 55 mcg per day, an adult intake of 100-200 mcg of selenium per day is recommended by many doctors.
Are there any side effects or interactions?
Selenium is safe at the level people typically supplement (100-200 mcg); however, taking more than 900 mcg of selenium per day has been reported to cause adverse effects in some people.13 Selenium toxicity can result in loss of fingernails, skin rash, and changes in the nervous system. In the presence of iodine-deficiency-induced goiter, selenium supplementation has been reported to exacerbate low thyroid function.14 The National Academy of Sciences recommends that selenium intake not exceed 400 mcg per day, unless the higher intake is monitored by a healthcare professional.15
Selenium enhances the antioxidant effect of vitamin E,.
“Selenium is an antioxidant which is believed by proponents to protect you from free radical attack. Free radicals are believed to lead to cancer. … Advocates argue that selenium helps reduce the incidence of breast, lung, colorectal and skin cancers.” (Ontario Breast Cancer Information Exchange Project. Guide to unconventional cancer therapies. 1st ed. Toronto: Ontario Breast Cancer Information Exchange Project, 1994:144) at http://www.bccancer.bc.ca/PPI/UnconventionalTherapies/Selenium.htm