Thorpe Matthew P, Jacobson Edward H, Layman Donald K, He Xuming, Kris-Etherton Penny M, Evans Ellen M
Division of Nutritional Sciences, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
J Nutr. 2008 Jun;138(6):1096-100. doi: 10.1093/jn/138.6.1096.
Weight loss causes bone mineral loss. Higher protein diets continue to be criticized for further potential harmful bone effects, including elevated urinary calcium, but may promote bone health if protein sources include dairy. Overweight middle-aged subjects (n = 130, 59 males) were randomized to a diet providing 1.4 g.kg(-1).d(-1) protein and 3 daily servings of dairy (PRO) or 0.8 g.kg(-1).d(-1) protein and 2 daily servings of dairy (CARB) for 4 mo of weight loss plus 8 mo of weight maintenance. Diets prescribed 6276 kJ/d for females and 7113 kJ/d for males. Bone mineral content and density (BMD) for whole body (WB), lumbar spine (LS) and total hip (TH) were measured using dual X-ray absorptiometry, and dietary intake using 3-d weighed food records. Urinary calcium was measured using 24-h collection at 0 and 8 mo for a subsample (n = 42). Participants lost body weight (mean, 95% CI) of 8.2% (7.5-8.9%) at 4 mo, 10.6% (9.5-11.8%) at 8 mo, and 10.5% (8.9-12.0%) at 12 mo without differences between groups at any time (P = 0.64). At 12 mo, PRO BMD was higher by 1.6% (0.3-3.0%) at WB, 2.1% (0.6-3.7%) at LS, and 1.4% (0.2-2.5%) at TH compared with CARB. PRO calcium intake was higher (PRO: 1140 +/- 58 mg/d, CARB: 766 +/- 46; P < 0.01), as was urinary calcium (PRO: 163 +/- 15 mg/d, CARB: 100 +/- 9.2; P < 0.01). A reduced-energy diet supplying 1.4 g.kg(-1).d(-1) protein and 3 dairy servings increased urinary calcium excretion but provided improved calcium intake and attenuated bone loss over 4 mo of weight loss and 8 additional mo of weight maintenance.
体重减轻会导致骨矿物质流失。高蛋白饮食因可能对骨骼产生进一步潜在有害影响（包括尿钙升高）而一直受到批评，但如果蛋白质来源包括乳制品，则可能促进骨骼健康。超重的中年受试者（n = 130，男性59名）被随机分配到一种饮食方案，一种方案是提供1.4 g·kg⁻¹·d⁻¹蛋白质和每日3份乳制品（PRO组），另一种方案是提供0.8 g·kg⁻¹·d⁻¹蛋白质和每日2份乳制品（CARB组），进行4个月的体重减轻期加8个月的体重维持期。规定女性饮食为6276 kJ/d，男性为7113 kJ/d。使用双能X线吸收法测量全身（WB）、腰椎（LS）和全髋部（TH）的骨矿物质含量和密度（BMD），并使用3天称重食物记录法记录饮食摄入量。对一个子样本（n = 42）在0个月和8个月时通过24小时尿液收集来测量尿钙。参与者在4个月时体重减轻（均值，95%可信区间）8.2%（7.5 - 8.9%），8个月时为10.6%（9.5 - 11.8%），12个月时为10.5%（8.9 - 12.0%），任何时候两组之间均无差异（P = 0.64）。在12个月时，与CARB组相比，PRO组的WB处BMD高1.6%（0.3 - 3.0%），LS处高2.1%（0.6 - 3.7%），TH处高1.4%（0.2 - 2.5%）。PRO组的钙摄入量更高（PRO组：1140 ± 58 mg/d，CARB组：766 ± 46；P < 0.01），尿钙也是如此（PRO组：163 ± 15 mg/d，CARB组：100 ± 9.2；P < 0.01）。一种提供1.4 g·kg⁻¹·d⁻¹蛋白质和3份乳制品的低能量饮食增加了尿钙排泄，但在4个月的体重减轻期和另外8个月的体重维持期内提供了更好的钙摄入量并减轻了骨质流失。
