2013-12-17

#quackwatch mineral supps deemed useless

12.17: web.health/selenium
/#quackwatch mineral supps deemed useless:
editorial by a medical journal:
"Fortmann et al reviewed trial evidence to update
the usa's Preeventive Services Task Force recommendation
on the efficacy of vitamin supplements
for primary prevention in community-dwelling adults
with no nutritional deficiencies .
[ and no mineral deficiencies -- notice that .]
. after reviewing 3 trials of multivitamin supplements
and 24 trials of single or paired vitamins
that randomly assigned more than 400,000 participants,
the authors concluded that there was no
clear evidence of a beneficial effect
of supplements on all-cause mortality,
cardiovascular disease, or cancer ."
". the only supplements not gaining in popularity
are beta-carotene (some uses increased lung cancer)
and vitamin E (some uses increased all-causes mortality)."
"... mineral supplements are ineffective for
preventing mortality or morbidity
due to major chronic diseases."
. since most cancers happen to the elderly,
cancer could be considered to be
"morbidity due to major chronic diseases";
so, the editor of this journal
seems to be asserting that
mineral supplementation would prevent no cancers .

. none of the study subjects had any
nutritional deficiencies .
. therefore they would not have benefited from
selenium supplementation;
but, not every region has proper selenium levels:
. the recommended dietary allowance for adults
is 55 μg selenium/d based on the intake required to
optimize plasma glutathione peroxidase activity .
Typical selenium intakes in North America are
80 to 140 μg/d [assumes you eat plenty of
grains and meat -- controversial .]
. Intakes in many parts of the world, however,
are lower largely due to low soil selenium levels.
. in some regions of China get less than
10 μg/d of selenium .
Intakes in Europe and New Zealand
range from less than 30 to 60 μg/d.
Clearly, diet does not meet selenium requirements.
. and regions with lower selenium levels
have higher rates of cancer .

. another factor affecting selenium usefulness
is the prevalence of other risk factors .
. if all the subjects were naive Americans,
feeding their cancers and heart blockages
with high levels of dirt-cheap corn syrup
(high doses of glucose and/or fructose),
then having sufficient selenium
is not likely to reduce cancer risk .

. grain-free vegetarians and many others
should definitely use selenium supplements .
. they may also benefit from magnesium, zinc,
and sea vegetables .