|
7th International Symposium on Nutritional Aspects of Osteoporosis
Lausanne, Switzerland
07.05.2009 - 09.05.2009 |
| Please enter your email address here in order to bring up your personal programme |
|
|
|
PosterThursday, May 07, 2009, 09:00 - 18:00A meta-analysis to quantify the contribution of dietary phosphate to the progression of osteoporosis under the acid-ash diet hypothesis T.R. Fenton, A.W. Lyon, M. Eliasziw, S.C. Tough, D.A. Hanley (Calgary, CAN)
The acid-ash hypothesis posits that the excretion of “acidic” ions derived from the diet, such as phosphate (PO4), contribute to calciuria, demineralization of bone, and osteoporosis.
The objectives of this meta-analysis were to quantify the contribution of PO4 to bone loss in healthy adult subjects; specifically, to assess the effect of PO4 on a) urine calcium and calcium balance, and to assess whether these affects are altered by the b) level of calcium intake, and c) the degree of protonation of the PO4 supplements.
Methods: Literature was identified through computerized searches regarding PO4 with surrogate and/or direct markers of osteoporosis. Studies were assessed for methodological quality.
Results: 12 studies including 32 interventions manipulated subjects’ PO4 intakes. None of the studies examined changes in bone mineral density or incidence of fractures. All of the meta-analyses demonstrated significant decreases in calciuria in response to the PO4. Increased PO4 intakes led to increased calcium retention. For a ten mmol increase of PO4 intake, calcium retention increased by 0.28 mmol/day (p < 0.001). b) When analyses were stratified by calcium intake: For a ten mmol increase of PO4 intake, calcium retention increased by 0.31 and 0.13 mmol/day, for the low and high calcium intake studies, respectively (p< 0.001 & p= 0.035). c) When analyses were stratified by acidic and non-acidic PO4 supplements: For a ten mmol increase of PO4 intake, calcium retention increased by 0.31 and 0.21 mmol/day, respectively (p= 0.115 & p< 0.001).
Conclusions: All of the findings from this meta-analysis were contrary to the acid ash hypothesis. Higher PO4 intakes were associated with decreased urine calcium and increased calcium retention. This meta-analysis did not find evidence that PO4 contributes to demineralization of bone and bone calcium excretion in the urine. Dietary advice that dairy products, meats, and grains are “acidic” due to PO4 content and therefore detrimental to bone health needs reassessment.
|
|
|