These results, which were recorded in a very homogeneous population of healthy postmenopausal women, indicate that there is a beneficial effect of animal and dairy protein intakes on bone strength and microstructure. Specifically, there is a positive association between the bone failure load and stiffness of the peripheral skeleton and dietary protein intake, which is mainly related to changes in the trabecular microstructure. This trial was registered at www.controlled-trials.com as ISRCTN11865958.
Background
The importance of dietary acid load (DAL) in the pathogenesis of osteoporosis is still debated. Age-related changes in bone microstructure and strength in relation to DAL remain largely unexplored.
Objectives
We investigated the associations between changes in areal and volumetric bone mineral density (BMD), bone microstructure and strength, fracture risk, and DAL in a prospective cohort of 65-y-old healthy men and postmenopausal women.
Methods
Potential renal acid load (PRAL; mEq/d) was calculated as a DAL proxy to characterize participants’ diet as alkaline (Alk-D; PRAL < −5), neutral (Neut-D; −5 ≤ PRAL ≤ 5), or acidic (Acid-D; PRAL >5). We measured areal BMD (aBMD) by DXA, and distal radius and tibia bone microstructure using high-resolution peripheral quantitative computed tomography, at baseline (n = 853) and after 6.1 ± 1.4 y (n = 708). Bone strength was estimated using finite element analyses at baseline and after 3.0 ± 0.5 y (n = 613). Prevalent and incident fractures were recorded.
Results
The majority of the participants (59%) had an Alk-D, while 23% had a Neut-D, and 18% an Acid-D. Baseline aBMD and bone microstructure and strength did differ or were slightly better in women or men with an Acid-D versus those consuming an Alk-D or Neut-D. Indeed, women with an Acid-D had higher trabecular number (P = 0.010 vs. Alk-D; P = 0.001 vs. Neut-D), while men had higher hip and radius aBMD (P = 0.008 and 0.024 vs. Neut-D, respectively) and radius strength (P = 0.026 vs. Neut-D). Over the follow-up, women in the Acid-D group experienced lower cortical and endocortical bone loss at the radius than did the Alk-D and Neut-D groups (cortical thickness, P = 0.008 and < 0.001; trabecular area, P = 0.001 and < 0.001, respectively). No association between fractures and PRAL was observed.
Conclusions
These null or favourable associations between baseline values or changes in aBMD, bone microstructure and strength, and DAL in this cohort of 65-y-old healthy individuals do not support adverse DAL-mediated effects on bone. This trial was registered at http://www.isrctn.com as ISRCTN11865958.
This study demonstrates the crucial influence of Prot-Int on the response to enhanced PA and the importance of prepubertal years for modifying the bone growth trajectory and, thereby, for achieving higher PBM and greater strength in healthy male participants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.