QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Thorpe, M. Articles by Evans, E. M. Search for Related Content PubMed PubMed Citation Articles by Thorpe, M. Articles by Evans, E. M. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Medline Plus Health Information Dietary Proteins Hazardous Substances DB SULFUR

---

Nutritional Epidemiology

A Positive Association of Lumbar Spine Bone Mineral Density with Dietary Protein Is Suppressed by a Negative Association with Protein Sulfur^1,2

³ Division of Nutritional Sciences, and ⁴ Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL 61801

^* To whom correspondence should be addressed. E-mail: elevans{at}uiuc.edu.

Dietary protein is theorized to hold both anabolic effects on bone and demineralizing effects mediated by the diet acid load of sulfate derived from methionine and cysteine. The relative importance of these effects is unknown but relevant to osteoporosis prevention. Postmenopausal women (n = 161, 67.9 ± 6.0 y) were assessed for areal bone mineral density (aBMD) of lumbar spine (LS) and total hip (TH) using dual X-ray absorptiometry, and dietary intakes of protein, sulfur-containing amino acids, and minerals using a USDA multiple-pass 24-h recall. The acidifying influence of the diet was estimated using the ratio of protein:potassium intake, the potential renal acid load (PRAL), and intake of sulfate equivalents from protein. aBMD was regressed onto protein intake then protein was controlled for estimated dietary acid load. A step-down procedure assessed potential confounding influences (weight, age, physical activity, and calcium and vitamin D intakes). Protein alone did not predict LS aBMD (P = 0.81); however, after accounting for a negative effect of sulfate (β = –0.28; P < 0.01), the direct effect of protein intake was positive (β = 0.22; P = 0.04). At the TH, protein intake predicted aBMD (β = 0.18; P = 0.03), but R² did not improve with adjustment for sulfate (P = 0.83). PRAL and the protein:potassium ratio were not significant predictors of aBMD. Results suggest that protein intake is positively associated with aBMD, but benefit at the LS is offset by a negative impact of the protein sulfur acid load. If validated experimentally, these findings harmonize conflicting theories on the role of dietary protein in bone health.

This article has been cited by other articles:

				E. Wynn, S. A. Lanham-New, M.-A. Krieg, D. R. Whittamore, and P. Burckhardt Low Estimates of Dietary Acid Load Are Positively Associated with Bone Ultrasound in Women Older Than 75 Years of Age with a Lifetime Fracture J. Nutr., July 1, 2008; 138(7): 1349 - 1354. [Abstract] [Full Text] [PDF]