Selenium
Requirements:
Daily Optimal Intake:
Therapeutic Dosage:
Supplement Forms:
- Selenomethionine - extracted from ocean plants or
selenium-rich yeast; least toxic and most absorbable
- Sodium selenite
- Sodium selenate
Labs:
- Hair analysis: acceptable level 1.0 - 5.0 ppm.
- Plasma: varies with intake but does not reflect body
stores
- RBC selenium and glutathione peroxidase activity: these have
also been used, but more variable than hair analysis
Food Sources:
- Animal sources found often as selenomethionine
- Found in protein fraction of foods: organ meats, fish, whole
grains, brewers yeast
Signs and Symptoms of Deficiency:
- Early signs: brittle nails and hair
Causes of Deficiency:
- Eating SAD (Standard American Diet)
- Areas with decreased soil selenium:
Industrial New England: New York, Connecticut
South East: Florida
North West: Oregon, Washington
Acid rain decreases selenium
Sulfate competes with selenium for uptake by plants
Fertilizers decrease selenium
Cooking often depletes selenium, especially if cooking water
is discarded
Adverse Effects and Toxicity:
- Large doses: hair loss, nail loss, nausea, vomiting, fatigue,
diarrhea, irritability, paresthesias, garlic odor
- Studies in high selenium areas suggest that chronic use of
1,000 mcg./day is safe
- Do not take on empty stomach
Drug/Nutrient Interactions:
- Enhances some effects of vitamin
E
- Concomitant administration of ascorbic acid may inactivate
sodium selenite when administered on an empty stomach
- Chronic alcohol use depletes selenium
- Gold therapy decreases bioavailability of selenium
- Glucocorticoids decrease plasma levels of selenium
Biochemical Functions:
- Cofactor for glutathione peroxidase
- Converts thyroxine to triiodothyronine
- Involved in arachidonic acid metabolism
- Involved in inflammatory response
- Binds heavy metals such as cadmium and mercury
Clinical Indications:
Copyright 1998 - 2008 by L. Vicky Crouse, ND and James S. Reiley, ND. All rights reserved (ISSN 1527-0661).