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15th
World Congress Clinical Nutrition
19th
– 22nd September 2010 El Sokhna Resort - Egypt
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Copyright © 2010.
WCCN2010.COM
All rights reserved |
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Mineral water, A model to
demonstrate the impact of calcium
and alkali on bone metabolism
Peter Burckhardt University
Lausanne, Switzerland
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Introduction:
Mineral waters (MW) are an
alternative to Ca (Ca) supplements
in the treatment and prevention of
osteoporosis. They can contain
300-500 mg/l of Ca. Their Ca lowers
PTH and increases BMD. Long-term
effects were mainly demonstrated in
Ca insufficiency. Although Ca in MW
is mostly linked to sulfate (acid
MW), some MW contain bicarbonate (Bic)
instead, are alkaline and increase
urine pH. Since intake of alkaline
food favors bone formation,
controlled interventional trials
with MW, whose PRAL could be
calculated, were reviewed. They
showed that bone resorption markers,
urinary Ca excretion, and PTH
decreased with the MW with the lower
PRAL values, independently of their
Ca content.
Methods and Results:
We tested Bic in MW, in groups of
normal, Ca-sufficient healthy women
over 4 weeks. First we compared a MW
with 361mg/1.5l Ca and 2528mg/1.5l
Bic, to a MW with 728 mg/1.5l Ca and
605 mg/1.5l Bic (N=2x10). Resorption
marker CTX in the fasting urine
decreased by 30% (sign.) with the
Bic-rich water, but not with the
Ca-rich water. Then, a MW rich in Ca
(822mg/1.5l) and in Bic (43258
mg/1.5l) was com-pared to a water
rich in Ca only (965mg/1.5l, Bic 158
mg/1.5l) (N=2x15). It increased pH
and Bic in the urine, and decreased
sign. CTX and pl.PTH, while the
Ca-rich water had no effect. Finally
an alkaline MW with 4483 mg/1.5l Bic,
but low Ca content (155 mg/1.5l) was
tested and was as ineffective on
bone as a MW with equally low
Ca-content (158mg/1.5l) and low Bic
(586mg/1.5l). Therefore, alkalinity
alone had no effect on bone.
Further, we analyzed the
correlations between the different
ionic constituents in 150 European
MW.
Comments,
conclusion: Because the PRAL value
of MW is in average conditioned by
Na for 53%, PRAL is not useful for
evaluating MW. In Ca sufficiency, MW
with a high Ca and bic content is
beneficial to bone, while MW rich in
bic or Ca only has no or less
demonstrable effect. MW rich in Ca
alone is beneficial in Ca deficien-cy.
In waters with a positive PRAL value
(acid MWs), Ca is predicted mainly
by SO4 (83.8% of the variation, p <
0.001). In alkaline MW with a
negative PRAL value, Ca is mainly
predicted by bic, which however
explains only 26.5% of the variation
(p < 0.001). This means, that most
MW with a high calcium content
contain relatively high
concentrations of SO4 and are
slightly acid, while alkaline MW,
which are rich in Ca and Bic, and
which are suitable for decreasing
bone resorption even in calcium
sufficiency, are rare.
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