Mangano Kelsey M, Walsh Stephen J, Kenny Anne M, Insogna Karl L, Kerstetter Jane E
Department of Nutritional Sciences, University of Connecticut, Storrs, CT, USA.
J Bone Miner Res. 2014 Feb;29(2):500-6. doi: 10.1002/jbmr.2053.
High dietary acid load (DAL) may be detrimental to bone mineral density (BMD). The objectives of the study were to: (1) evaluate the cross-sectional relation between DAL and BMD; and (2) determine whether calcium intake modifies this association. Men (n = 1218) and women (n = 907) aged ≥60 years were included from the National Health and Nutrition Examination Survey 2005-2008. Nutrient intake from 2, 24-hour recalls was used to calculate net endogenous acid production (NEAP) and potential renal acid load (PRAL) (mEq/d). PRAL was calculated from dietary calcium (PRALdiet ) and diet + supplemental calcium (PRALtotal ). Tests for linear trend in adjusted mean BMD of the hip and lumbar spine were performed across energy-adjusted NEAP and PRAL quartiles. Modification by calcium intake (dietary or total) above or below 800 mg/d was assessed by interaction terms. Overall, mean age was 69 ± 0.3 years. Among women, there was no association between NEAP and BMD. PRALdiet was positively associated with proximal femur BMD (p trend = 0.04). No associations were observed with PRALtotal at any BMD site (p range, 0.38-0.82). Among men, no significant associations were observed between BMD and NEAP or PRAL. However, an interaction between PRALdiet and calcium intake was observed with proximal femur BMD (p = 0.08). An inverse association between PRALdiet and proximal femur BMD was detected among men with <800 mg/d dietary calcium (p = 0.02); no associations were found among men with ≥800 mg/d (p = 0.98). A significant interaction with PRALtotal was not observed. In conclusion, when supplemental calcium is considered, there is no association between DAL and BMD among adults. Men with low dietary calcium showed an inverse relation with PRAL at the proximal femur; in women no interaction was observed. This study highlights the importance of calcium intake in counteracting the adverse effect of DAL on bone health. Further research should determine the relation between DAL and change in BMD with very low calcium intake.
高膳食酸负荷（DAL）可能对骨矿物质密度（BMD）有害。本研究的目的是：（1）评估DAL与BMD之间的横断面关系；（2）确定钙摄入量是否会改变这种关联。研究纳入了2005 - 2008年美国国家健康与营养检查调查中年龄≥60岁的男性（n = 1218）和女性（n = 907）。通过2次24小时饮食回忆来获取营养素摄入量，以计算净内源性酸产生量（NEAP）和潜在肾酸负荷（PRAL）（mEq/d）。PRAL根据膳食钙（PRALdiet）和膳食 + 补充钙（PRALtotal）来计算。对能量调整后的NEAP和PRAL四分位数进行髋部和腰椎调整后平均BMD的线性趋势检验。通过交互项评估钙摄入量（膳食或总摄入量）高于或低于800 mg/d时的修正情况。总体而言，平均年龄为69±0.3岁。在女性中，NEAP与BMD之间无关联。PRALdiet与股骨近端BMD呈正相关（p趋势 = 0.04）。在任何BMD部位，PRALtotal均未观察到关联（p范围为0.38 - 0.82）。在男性中，BMD与NEAP或PRAL之间未观察到显著关联。然而，在股骨近端BMD方面，观察到PRALdiet与钙摄入量之间存在交互作用（p = 0.08）。在膳食钙摄入量<800 mg/d的男性中，检测到PRALdiet与股骨近端BMD呈负相关（p = 0.02）；在膳食钙摄入量≥800 mg/d的男性中未发现关联（p = 0.98）。未观察到与PRALtotal的显著交互作用。总之，考虑补充钙后，成年人中DAL与BMD之间无关联。膳食钙摄入量低的男性在股骨近端PRAL与之呈负相关；在女性中未观察到交互作用。本研究强调了钙摄入量在抵消DAL对骨骼健康不利影响方面的重要性。进一步的研究应确定极低钙摄入量时DAL与BMD变化之间的关系。
