School of Kinesiology and Health Science, Faculty of Health, York University, 4700 Keele Street, Toronto, ON, Canada.
Centre for Bone and Muscle Health, Faculty of Applied Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, Canada.
Pediatr Res. 2020 Dec;88(6):910-916. doi: 10.1038/s41390-020-0834-5. Epub 2020 Mar 16.
We examined whether increased dairy intake was associated with changes in the levels of bone-related biochemical markers in overweight/obese adolescent girls undergoing a 12-week diet and exercise intervention.
Thirty-five girls were assigned to a low dairy group (LDa; 0-2 servings/day; n = 16) or a higher dairy group (RDa; 4 servings/day; n = 19). Morning, fasted/resting blood samples were collected before and after the intervention and serum concentrations of procollagen-type-1-N-terminal-propeptide (P1NP), β-isomerized-C-terminal-cross-linking-telopeptides (β-CTX), osteocalcin (OC), 25-hydroxyvitamin-D, sclerostin and parathyroid hormone were measured.
At baseline, there were no significant differences between groups in any bone variable. Changes (∆) over time in β-CTΧ (p = 0.035; interaction) and OC (p = 0.015; interaction) were significantly different between groups characterized by decreases in RDa and increases in LDa. P1NP and P1NP:β-CTX ratio decreased in both groups (main time effects: p = 0.003, p = 0.041, respectively). ∆β-CTX (r = -0.37; p = 0.028) and ∆OC (r = -0.39; p = 0.021) were correlated with average number of dairy servings consumed during the study and with each other (r = 0.45; p = 0.006). ∆OC was not correlated with ∆P1NP (r = 0.19; p = 0.27).
Our results suggest that the osteogenic response to a diet and exercise program in this population can be improved with increased dairy intake via a decrease in bone resorption.
We demonstrated that bone resorption significantly decreased over the intervention period in the group consuming adequate levels of dairy products compared to the group consuming little to no dairy products. Change in bone resorption was negatively correlated with average number of dairy servings consumed during the study. Our results suggest that the osteogenic response to a diet and exercise program in this population can be improved with increased dairy intake via a decrease in bone resorption. This is the first study to date to assess changes in bone marker status following a lifestyle intervention with exercise and different intakes of dairy products in a sample of OW/OB adolescent girls. We provide evidence that increased dairy product intake is associated with beneficial changes in circulating levels of bone-related biochemical markers in these girls undergoing a 12-week lifestyle (nutrition counseling and exercise training) intervention program. The main impact of our work relates particularly to the recent changes to Canada's food guide. Using the old recommendations, we demonstrated that the inclusion of 3-4 servings of mixed dairy foods per day improved bone health (primarily as a decrease in resorption) in OW/OB adolescent girls and that this level of dairy product intake appears appropriate and should still be encouraged for this age group. We also demonstrated that adolescent girls, a group that usually does not sufficiently consume dairy products, also improved their BMI percentile and nutrient intake with the inclusion of dairy products in their diets.
我们研究了超重/肥胖青少年女性在进行 12 周饮食和运动干预时，增加乳制品摄入量是否与骨相关生化标志物水平的变化有关。
35 名女孩被分配到低乳制品组（LDa；0-2 份/天；n=16）或高乳制品组（RDa；4 份/天；n=19）。干预前后采集清晨空腹/休息时的血样，测量血清中前胶原型 1-N 端前肽（P1NP）、β-异柠檬酸交联端肽（β-CTX）、骨钙素（OC）、25-羟维生素 D、硬化蛋白和甲状旁腺激素的浓度。
在基线时，两组之间在任何骨变量上均无显著差异。RDa 组下降而 LDa 组增加时，β-CTX（p=0.035；交互作用）和 OC（p=0.015；交互作用）的变化（∆）在组间存在显著差异。两组的 P1NP 和 P1NP：β-CTX 比值均降低（主要时间效应：p=0.003，p=0.041）。β-CTX（r=-0.37；p=0.028）和 OC（r=-0.39；p=0.021）的变化与研究期间平均乳制品摄入量呈负相关，且两者之间呈正相关（r=0.45；p=0.006）。OC 的变化与 P1NP 的变化无相关性（r=0.19；p=0.27）。
我们的结果表明，通过降低骨吸收，增加乳制品摄入可以改善该人群饮食和运动方案的成骨反应。
与摄入少量或不摄入乳制品的组相比，摄入足量乳制品的组在干预期间骨吸收明显减少。骨吸收的变化与研究期间平均乳制品摄入量呈负相关。我们的结果表明，通过降低骨吸收，增加乳制品摄入可以改善该人群饮食和运动方案的成骨反应。这是迄今为止评估在 OW/OB 青少年女性样本中进行的运动和不同乳制品摄入量的生活方式干预后骨标志物状态变化的第一项研究。我们提供的证据表明，在接受 12 周生活方式（营养咨询和运动训练）干预方案的女孩中，增加乳制品的摄入与循环中与骨相关的生化标志物水平的有益变化有关。我们工作的主要影响特别是与加拿大食物指南的最新变化有关。使用旧的推荐，我们表明，每天摄入 3-4 份混合乳制品可以改善超重/肥胖青少年女性的骨健康（主要是通过降低吸收），并且这种乳制品的摄入水平似乎是合适的，仍应鼓励该年龄组摄入。我们还表明，通常不能充分摄入乳制品的青少年女孩，在饮食中加入乳制品也可以提高其 BMI 百分位数和营养摄入。
