There has never been a study to test the effects on lifespan
of the trace mineral selenium, but an early study, which
examined the toxicity of selenium (and other minerals) found,
by accident, that it extended the lifespan of laboratory mice.
There have been dozens of studies showing that dietary selenium
can help to prevent a wide variety of cancers, and that it may
be useful in the treatment of cancer. Anyone taking selenium on
a daily basis for antiaging purpose should be careful to keep
their doses low to avoid the possibility of toxic side effects.
Selenium, an essential trace element, is involved in the development
of mammalian sperm and protection against heart disease and cancer.
A cofactor of glutathione peroxidase, it is also involved in the
regulation of glycoprotein production and cellular respiration.
Other biologically active proteins contain selenium, including
the enzyme that converts inactive thyroid hormone (T4) to its
active form (T3).
Most people are likely to consume too little selenium rather
than too much; highly stressed people and vegetarians probably
require more. The incidence of some diseases is lower in areas
where the soil selenium content of crops is higher. China, New
Zealand, and Scandinavia have selenium-poor soils.
Individuals on a low selenium diet showed a rapid increase in
plasma selenoprotein following supplementation with selenium.
A review of over 200 epidemiologic studies found that selenium
is among a group of fruit and vegetable-derived substances that
show particular promise in cancer prevention. A recent review
of the scientific literature revealed that preliminary observations
also suggest that a low serum selenium concentration is associated
with increased platelet aggregation, low high-density lipoprotein
(HDL) cholesterol and elevated blood pressure.
Animals receiving a selenium- and retinoic acid-supplemented
diet experienced significantly fewer chemically induced tumors
than non-supplemented animals. In a large-scale 5-year study,
subjects receiving selenium, beta-carotene and vitamin E supplementation
had reduced total and cancer mortality, when compared with three
other supplement groups. Another large-scale study showed that
selenium supplementation is an effective preventative agent against
to Anti-Aging Medicine Index