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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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Effect of Bicarbonate
Supplementation on Bone and Muscle
in Older Men and Women
Suzan Harris , Bess Dawson-Hughes,
Boston, MA USA
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Muscle weakness and frailty in the
elderly lead to falls, fractures,
disability, and loss of
independence. Preserving muscle mass
and strength is an effective way to
lower risk of falling and reducing
falls and preserving bone mass are
effective means of reducing fracture
risk and preserving physical
function and independence. With
aging there is a gradual increase in
the circulating [H+] that results
from the combination of
acid-producing diets (diets rich in
protein and cereal grains relative
to their content of fruits and
vegetables) and age-related declines
in renal function. Renal
insufficiency impairs acid-base
homeostasis by reducing bicarbonate
conservation and acid excretion.
Mild metabolic acidosis produces net
bone resorption by a variety of
mechanisms and it may increase rates
of bone loss, although the evidence
is mixed. There is limited evidence
that it promotes muscle wasting.
Objective: To
determine the effects of potassium
bicarbonate and its components on
selected changes in bone turnover
markers and muscle performance in
older men and women.
Study design: In a
double-blind, controlled trial, 171
men and postmenopausal women age 50
years and older were randomized to
treatment with placebo or 67.5 mmol
of potassium bicarbonate, sodium
bicarbonate, or potassium chloride
daily for 3 months. The main
outcomes were 24-hr urinary NTX and
calcium excretion, nitrogen
excretion, and muscle power and
endurance. Changes in these measures
were compared across treatment
groups.
Results:
Bicarbonate significantly reduced
each of these measures whereas
potassium had no effect, therefore
the two bicarbonate and the two no
bicarbonate (control) groups were
combined for further analyses.
Subjects supplemented with
bicarbonate had significantly
greater mean changes in calcium/Cr
excretion (P = 0.002) and urinary
NTX/Cr (P = 0.002) than subjects in
the control group, after adjustment
for sex, baseline value, and changes
in sodium/Cr and K/Cr excretion.
Moreover, after three months on
treatment, NAE/Cr was significantly
associated with NTX/Cr (adjusted β =
0.18, P < 0.001). With respect to
the muscle-related findings, there
was a significant interaction of sex
and so men and women were analyzed
separately. Bicarbonate
significantly reduced nitrogen
excretion (P = 0.004) and reduced
double leg press power at 70% one
repetition maximum by 13% (P =
0.003) in the women but not in the
men. The reason for the attenuated
effect of bicarbonate on the muscle
outcomes in the men may be that the
men received a lower dose than the
women on a weight basis, but this
explanation remains speculative.
Conclusion:
Bicarbonate supplementation appears
to be a promising strategy to
improve bone and muscle status in
older adults; however, the optimal
dose and the long-term effects of
bicarbonate on bone and muscle
remain to be determined.
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