Cardiovascular
diseases are, as a group, the leading cause of death in western countries.
Sudden
death from cardiovascular disease accounts for over 300,000 deaths per year in
the U.S. Because of the importance of preventing cardiovascular diseases, major
efforts have been made to identify risk factors and to take steps to reduce
these risks.
The
findings of a six-year study of more than 20,000 healthy men and women aged
38-100 in the May 1, 2002 issue of the American Journal of Epidemiology found
that women who drank more than five glasses of water a day were 41% less likely
to die from a heart attack during the study period than those who drank less
than two glasses.
The
protective effect of water was even greater in men.
There
is an increasing body of evidence that drinking water hardness and
elevated concentrations of certain minerals in
hard water may reduce the risk of cardiac death and, in particular, the risk of
sudden cardiac death.
Recent
interest has focused on deficits in dietary magnesium. In developed countries,
these deficits are potentially compounded by use of medications, such as diuretics,
that further reduce body stores of magnesium.
To
minimize heart disease risk, the ideal water should contain sufficient calcium
and magnesium to be moderately hard.
No
effort should be made to eliminate trace elements such as copper and iron where
these elements are in short, dietary supply.
Elements
such as cadmium and lead,
which can accumulate in the body, should be minimized.
There
is also concern that increased use of calcium supplements to prevent osteoporosis may
alter the ratio of calcium to magnesium intake, further exacerbating the
deficiency in magnesium intake.
Since
calcium and magnesium compete for absorption, there is concern that increasing
calcium intake without also increasing magnesium intake can result in a deficit
of magnesium. The optimal ratio of calcium to magnesium is unknown.
In
this chapter, the plausibility of a relationship between waterborne and
dietary magnesium ingestion and cardiac disease is discussed, primarily in
terms of persons who are on magnesium therapy or participate in rigorous
exercise.
In
particular, can studies of these two high-risk populations provide evidence for
or against the hypothesis of a causal relationship between water hardness and
the risk of cardiovascular disease?
A
recent study tracked 7,172 men in the Honolulu Health Program. Baseline
measurements were made between 1965 and 1968. Over a 30-year period follow-up
1,431 men developed coronary heart disease.
There
was a statistically significant increased risk of coronary heart disease in men
in the lowest versus the highest quintiles of baseline magnesium intake after
adjusting for other dietary and non-dietary cardiovascular disease risk factors
both of which were also ascertained at baseline.
They
did not present data on both calcium and magnesium intake
for the various quintiles, making it impossible to determine the calcium to
magnesium ratio. An interesting finding, however, was that systemic
hypertension decreased with increasing magnesium intake.
Unfortunately,
in assessing the effects of both calcium and magnesium, some papers have
adjusted for blood pressure, which appears to be an intermediate outcome of
increased magnesium intake.
By
adjusting for such an intermediate outcome one can falsely conclude that calcium is
protective but that magnesium has no effect on heart disease risks.
In
reality the effect of magnesium on heart disease could be through its effect on
lowering blood pressure.
Related Posts:
http://www.freedrinkingwater.com/water_health/health1/1-get-healthier-heart-with-water.htm
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