Selenium

Selenomethionine

Selenium essentiality was first discovered in 1957 when Schwartz and Foltz showed that traces of dietary selenium prevent liver necrosis in those fed a diet also deficient in vitamin E. In the 1960s and 1970s epidemiological data began to demonstrate that selenium also possesses anti-carcinogenic activity. Since the discovery that GLUTATHIONE PEROXIDASE (GSH) is a seleno-enzyme, a total of 18 seleno-enzymes or seleno-proteins have been discovered.

ANTIOXIDANT - The trace mineral selenium functions primarily as a component of the antioxidant enzyme glutathione peroxidase, which works with vitamin E in preventing free radical damage to cell membranes. A high concentration of selenium is found within GSH in sperm and within the testis. In a double-blind trial, selenium supplementation of infertile men improved the motility of sperm cells and increased the chance of conception.
CELLULAR PROTECTION - 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. Another study found that men consuming the most dietary selenium developed 65% fewer cases of advanced prostate cancer than did men with the lowest levels of selenium intake.
IMMUNE SUPPORT - Selenium's involvement in the production of glutathione peroxidase affects all aspects of immunity. Selenium supplementation results in augmentation and/or restoration of immune function, stimulating white blood cell and thymus function. Selenium supplementation has reduced the incidence of viral hepatitis in selenium-deficient populations, presumably by enhancing immune function. Even in a non-deficient population of elderly people, selenium supplementation has been found to stimulate the activity of white blood cells-primary components of the immune system.
ANTI-INFLAMMATORY - Selenium and GP levels are low in inflammatory conditions such as rheumatoid arthritis, eczema, and psoriasis. GP is especially important in reducing inflammatory prostaglandins and leukotrienes.
THYROID SUPPORT - Selenium is involved with the production of thyroid hormone. Recent research has shown selenium to be a useful treatment in thyroid auto-immune disorders (auto-immune thyroiditis).
CATARACT PREVENTION - The development of cataracts is ultimately related to free-radical damage. The lens of the eye requires adequate levels of SOD, catalase, and GP. Studies have demonstrated that low selenium levels have been found in cataract sufferers.
CARDIOVASCULAR PROTECTION - Selenium supplementation appears to increase HDL to LDL cholesterol and inhibit platelet aggregation (blood stickiness). The overall benefits on the cardiovascular system stem from the antioxidant effects of glutathione peroxidase.
PREGNANCY AND PRENATAL CARE - Selenium has been shown to be essential for normal foetal growth and development. Selenium levels also appear to be very low in low birth weight babies.

Dosage

200µg one to three times daily. Selenium is safe at the level people typically supplement (100-200µg); however, taking more than 900µg of selenium per day has been reported to cause adverse effects in some people. Intakes of 75 per day may result in biochemical abnormalities. Much higher levels may produce similar symptoms to that of deficiency.

Potential applications

Selenium has a broad range of activities and potential applications including; cancer prevention, cardiovascular disease, male infertility, foetal health and development, thyroid regulation, anti-viral (particularly Coxsackie virus), HIV, elevated cholesterol (LDL), inflammatory conditions e.g. psoriasis and asthma. Other responsive conditions include auto-immune disorders, (e.g. Multiple sclerosis, thyroiditis), cataracts and acne.

Known contraindications

None known.

Interactions

Copper and selenium appear to interact, with copper deficiency giving rise to decreased activity of GSH. Many toxic elements such as; lead, cadmium, mercury, and gold possess selenium-antagonistic properties. Selenium also interacts with the amino acid methionine. Dietary selenium is found as selenomethionine. Thus the potency of selenium in this form may be reduced if a situation of methionine deficiency exists. Supplemental seleno-methionine helps overcome this concern. Deficiency of both vitamin E and selenium has been shown to increase markers of free radical damage on polyunsaturated fatty acids.

Use in conjunction with

Cellular protection - vitamin E, alpha lipoic acid, coenzyme Q10, flax seed oil, blue food blend

Note

Selenium deficiency in humans is known as Keshan's disease. This condition results in dry flaky skin, loss of hair and skin pigmentation, whitening of nail beds, bilateral muscle discomfort, and pain, and cardiomyopathy. Thyroid and reproductive problems are common, along with the appearance of the Coxsackie virus.

REFERENCES

Michael Murray. 1996. The Encyclopaedia of Nutritional Supplements. P. 44-53
Bowman and Russell. 2001. Present Knowledge in Nutrition. Eighth Edition.
James L. Groff, Sareen S. Gropper, Sara M. Hunt. 1995. Advanced Nutrition and Human Metabolism. 2nd Edition.
Falciglia HS, Johnson JR, Sullivan J, Hall CF, Miller JD, Riechmann GC, Falciglia GA. Role of antioxidant nutrients and lipid peroxidation in premature infants with respiratory distress syndrome and bronchopulmonary dysplasia. Department of Pediatrics, Division of Neonatology and Pulmonary Biology, Children's Hospital, Cincinnati, Ohio. Am J Perinatol 2003 Feb;20(2):97-108
Duntas LH, Mantzou E, Koutras DA.. Effects of a six Month treatment with selenomethionine in patients with autoimmune thyroiditis. Endocrine Unit, Evgenidion Hospital, University of Athens Medical School, 20 Papadiamantopoulou Str, 11528 Athens, Greece. Eur J Endocrinol 2003 Apr;148(4):389-393

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