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Selenium ~ You simply cannot lack this mineral!
Selenium
is a mineral we are only just learning about. It was not
even discovered as an essential nutrient until 1979 and
only in 1990 was an RDA recommended. It is now known to
work with vitamin F and Glutathione Peroxidase to help protect
the body's tissues from free radical damage. Selenium and
vitamin F seem to correct a deficiency in each other. Selenium
also appears to be anti-viral and anti-bacterial in its
actions.
Selenium
has two other effects that may well play a role against
cancer. Firstly, it protects the body against the increasing
problem of toxic metals, e.g. mercury, copper and arsenic.
This is particularly relevant in the case of mercury, which
pollutes, via local coastal fish, fillings in our teeth
and vaccines. The FDA in the USA identified four years ago
that 83 of the 100 most common vaccines used mercury as
the carrier - by asking nicely they have reduced this to
73!!
Secondly,
selenium levels affect your hormones - in particular, the
thyroid hormone, from which it removes the iodine. This
has a knock-on effect to all of your hormones.
Various
studies have looked at the blood selenium levels of people
from different parts of the globe and the conclusion is
invariably that low levels are linked to higher cancer rates.
In
1984 researchers at the University of Kuopio in Finland
looked at 8000 women and men who were interviewed and blood
samples stored. In the following years 128 men developed
cancer. When their blood was compared to those without cancer
it was found to be deficient in selenium - in fact those
with the lowest levels were three times more likely to develop
cancer. This was especially true for cancers of the blood
and colon.
A
second study by universities all over the USA looked at
11,000 people across 5 years. 111 of the participants developed
cancer and again their selenium levels were much lower than
healthy people tested. In this research the cancers most
noted were again those of the gastrointestinal tract, but
also prostate cancer.
By contrast selenium does not appear to influence breast
cancer rates - the Harvard Medical School study on 62,000
nurses was inconclusive.
Males
appear to have a slightly greater selenium requirement.
It is lost in the semen and concentrates in the testes and
seminal ducts.
One
of the most important cancer trials was undertaken by the
Nutritional Prevention of Cancer Study Group, (Effects of
Selenium Supplementation for Cancer Prevention in Patients
with Carcinoma of the Skin, Larry Clark eta! - JAMA,1996)
and utilised a 0.5-g high-selenium brewers yeast tablet
providing 200 mcg of selenium per day. 1312 patients participated.
This study showed that there was no effect on skin cancers
in the group taking selenium, but a 52 per cent reduction
in total cancer mortality, a 17 per cent reduction in all
cause mortality, a 37 per cent reduction in total cancer
incidence, a 46 per cent reduction in lung cancer
incidence, a 58 per cent reduction in colon cancer incidence
and a 63 per cent reduction in prostate cancer incidence.
And this is in a group of patients in the United States
where selenium intake from the diet is approximately 2-3
times higher than that in the UK and Europe in general.
Much
work has also been done with the population of China where
there are both selenium rich areas and selenium deficient
areas. Research there suggests that selenium has a 20 per
cent positive effect on cancer risk.
Currently
Dr. Margaret Rayman, from Surrey University, a world expert
in selenium is involved in the Precise study. Given a 5
star rating by the Medical Research Council, this is a major
European trial (involving 35,000 participants Europe-wide)
investigating the effect of supplementation on cancer at
different doses. Funding is an issue at £2 million
but hopefully will be sorted out soon.
Recommended
daily levels and supplementation
The
RDA is around 55 micrograms. It is felt that levels around
200 micrograms are probably beneficial but above that there
is concern. At 900 micrograms there is proven toxicity,
which manifests itself in dermatitis, hair loss and diseased
nails.
Selenium
yeast is the form of selenium used in the recent and most
encouraging cancer trials, although usually this is not
a live yeast. Someone who has a massive yeast overgrowth
problem might need to stay away from yeast for a while,
but this should not affect everyone.
Selenium
yeast is the form of selenium used in the recent and most
encouraging cancer trials, although usually this is not
a live yeast. Someone who has a massive yeast overgrowth
problem might need to stay away from yeast for a while,
but this should not affect everyone.
Selenium
yeast provides selenium compounds similar to those found
in cereals, so closely resembles a food, which is ideal
for a food supplementation (approx. 50% of the selenium
compounds found in yeast comprise of selenomethionine).
Seleno-methionine is another organic form and, whilst inorganic
forms such as selenite and selenate are not naturally found
in foods, they have been found to produce higher levels
of glutathione peroxidase quicker. This is only one selenium
dependant enzyme in the body and there are 35 or more selenoproteins
that have been identified to date which all rely on selenium
for their function. Bioavailability studies have shown that
the inorganic forms of selenium are less bioavailable than
organic forms.
Eating
the vitamins
Try
Brazil nuts, wholemeal bread, sunflower and pumpkin seeds,
free-range eggs, skinless chicken breast, tuna fish, onions,
wheat germ, tomatoes and broccoli. There is even a selenium-enriched
form of garlic, which is giving strong anticancer results.
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