Moderate selenium deficiency is associated with increased risk of chronic disease: cancer, heart disease, thyroid disorder. Conversely, a selenium supplement containing one hundred (100) micrograms of selenium daily could reduce the risk of serious, age-related diseases in persons with moderate selenium deficiency, according to the known researcher Bruce Ames’ so-called triage theory.
Researchers Joyce McCann and Bruce Ames from Children’s Hospital Oakland Research Institute (CHORI) have analyzed the data from hundreds of scientific articles. They conclude that some selenium-dependent proteins that are regarded as essential for the body’s survival in the period until humans reach reproductive age are much more resistant to selenium deficiency than are other non-essential selenoproteins.
The triage theory
The new study supports Dr. Ames’ triage theory first proposed in 2006 in the journal PNAS explaining why age-related diseases like heart disease, cancer, and dementia could be the unintended consequences of mechanisms that have been developed throughout human evolutionary history to protect us from periodic vitamin and mineral deficiencies.
The concept of Triage – the word comes from the French verb Trier meaning to sort, separate, or select – was developed during the Napoleonic wars, when there was a need for a system that would give priority treatment to the wounded based on their likely chances of survival. This system of triage could quickly identify the soldiers who soon could return to battle following treatment.
Dr. Ames’ theory is similar to this principle; the theory proposes that the moderate deficiency of any vitamin or mineral could increase the risk of age-related diseases. Vitamin and mineral-dependent proteins required for short-term survival and/or for reproduction are categorized as “essential” and are predicted to be protected in cases of vitamin and mineral deficiency over other “non-essential” vitamin and mineral-dependent proteins needed only for long-term health. The prioritizing short-term survival needs over long-term health needs is a prioritizing that the body is forced to make in deficiency conditions. However, the result is the accumulation of hidden cell or protein damage, increasing the risk of chronic degenerative disease over time.
The researchers have previously successfully tested the theory on vitamin-K.
Short-term emergency
A good example supporting Dr. Ames’ triage theory is seen when calcium is released from the bone to the blood as a short-term survival response to neutralize the acid excess in the blood resulting from a high protein intake. This “short term” emergency action that the body takes often has a long term consequence in the development of osteoporosis.
The triage theory is a way of measuring the insidious damage that may be going on over time. Dr. Ames explains that triage theory is his attempt to provide a rationale for a solid nutritional foundation,
Ranking selenoproteins
In their new study, McCann and Ames analyzed the activity and concentration of about half of the 25 known selenoproteins in mammals. They ranked five selenoproteins as essential and seven selenoproteins as nonessential; they discovered that the activity and levels of the nonessential selenoproteins were preferentially lost when the organism was suffering from moderate selenium deficiency.
This result strongly supports Dr. Ames’ theory that among all selenoproteins, the malfunction of the nonessential selenoproteins is likely to be a major cause of increased risk of chronic degenerative disease.
Implications for Recommended Dietary Allowances (RDA)
The current RDA of 55 micrograms of selenium per day, which is equivalent to about 100 micrograms per liter of plasma selenium, is a recommendation that is based on the maximum activity in the blood selenium enzyme glutathione peroxidase (GPX). Drs. McCann and Ames consider that the current RDA may be insufficient because a vital selenium dependent protein called SEPP1 has proved to be more sensitive to selenium deficiency than GPX.
McCann and Ames suggest that the RDA for selenium should be established at a level that replenishes SEPP1 concentrations; they says that the RDA should be increased to 75 micrograms a day.
The European Union’s upper tolerable limit for selenium is set at 300 micrograms per day.
Sources
McCann, J. C., & Ames, B. N. (2011). Adaptive dysfunction of selenoproteins from the perspective of the triage theory: why modest selenium deficiency may increase risk of diseases of aging. FASEB Journal: Official Publication Of The Federation Of American Societies For Experimental Biology, 25(6), 1793-1814.
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