Screening Department, Institute of Mother and Child, Kasprzaka 17A, 01-211 Warsaw, Poland.
Department of Epidemiology and Biostatistics, Institute of Mother and Child, Kasprzaka 17A, 01-211 Warsaw, Poland.
Clin Nutr. 2019 Apr;38(2):730-737. doi: 10.1016/j.clnu.2018.03.010. Epub 2018 Mar 23.
BACKGROUND & AIMS: Measurements of bone mineral density (BMD) reflect bone status but not the dynamics of bone turnover. Biochemical markers, which show global skeletal activity, were validated for the assessment of bone formation and resorption processes. Adipokines also play a significant role in the regulation of bone metabolism.
To assess body composition, bone mineral density, bone turnover markers and adipokine levels in relation to vegetarian and omnivorous diets.
The study included 53 vegetarian and 53 omnivorous prepubertal healthy children matched for age and sex (median age 7.0 years). Body composition and BMD were assessed by dual-energy X-ray absorptiometry. 25-hydroxyvitamin D and parathormone levels were measured by chemiluminescence method. Serum carboxy-terminal propeptide of type I collagen (CICP), total osteocalcin (OC) and its forms carboxylated (c-OC) and undercarboxylated (uc-OC), C-terminal cross-linking telopeptide of collagen type I (CTX), leptin and adiponectin levels were determined using immunoenzymatic assays.
Both groups of children were comparable in terms of body composition, except for the percentage of fat mass, which was lower (19.24 vs. 21.77%, p = 0.018) in vegetarians. Mean values of total BMD z-score and lumbar spine BMD z-score were lower (-0.583 vs. -0.194, p = 0.009 and -0.877 vs. -0.496, p = 0.019, respectively) in vegetarians compared with omnivores. Serum leptin level was about 2-fold lower (1.39 vs. 2.94 ng/mL, p < 0.001) in vegetarians, however, adiponectin concentration was similar in both groups. Vegetarians had similar concentration of 25-hydroxyvitamin D, but higher parathormone (40.8 vs. 32.1 pg/mL, p = 0.015) and CTX (1.94 vs. 1.76 ng/mL, p = 0.077) levels than omnivores. Total osteocalcin and CICP concentrations were comparable in both groups, however, c-OC/uc-OC ratio was higher (1.43 vs. 1.04 ng/mL, p < 0.05) in vegetarians. We found positive correlation between c-OC and nutritional parameters adjusted for total energy intake (plant protein, phosphorus, magnesium and fiber intakes) in vegetarian children.
Prepubertal children on a vegetarian diet had significantly lower total and lumbar spine BMD z-scores, but absolute values of bone mineral density did not differ. BMD z-scores did not correlate with bone metabolism markers and nutritional variables, but were positively associated with anthropometric parameters. Lower leptin levels in vegetarian children reflect lower body fat. Longitudinal studies are necessary to evaluate the impact of the observed association on bone health at adulthood.
骨矿物质密度（BMD）的测量反映了骨骼状况，但不能反映骨转换的动态变化。生化标志物可全面反映骨骼活性，已被验证可用于评估骨形成和吸收过程。脂肪因子在骨代谢调节中也起着重要作用。
评估与素食和杂食饮食相关的身体成分、骨矿物质密度、骨转换标志物和脂肪因子水平。
本研究纳入了 53 名素食和 53 名杂食的青春期前健康儿童，按年龄和性别匹配（中位数年龄 7.0 岁）。采用双能 X 射线吸收法评估身体成分和 BMD。采用化学发光法测量 25-羟维生素 D 和甲状旁腺激素水平。使用免疫酶联测定法测定血清Ⅰ型胶原羧基端肽（CICP）、总骨钙素（OC）及其羧化（c-OC）和非羧化（uc-OC）形式、Ⅰ型胶原 C 端交联肽（CTX）、瘦素和脂联素水平。
两组儿童在身体成分方面除体脂百分比（素食者为 19.24%，杂食者为 21.77%，p=0.018）外，其他方面均无差异。素食者的总 BMD z 评分和腰椎 BMD z 评分分别低于杂食者（-0.583 对-0.194，p=0.009 和-0.877 对-0.496，p=0.019）。素食者的瘦素水平约低 2 倍（1.39 对 2.94ng/ml，p<0.001），但脂联素浓度在两组间无差异。素食者的 25-羟维生素 D 浓度相似，但甲状旁腺激素（40.8 对 32.1pg/ml，p=0.015）和 CTX（1.94 对 1.76ng/ml，p=0.077）水平更高。两组的总骨钙素和 CICP 浓度相似，但素食者的 c-OC/uc-OC 比值更高（1.43 对 1.04ng/ml，p<0.05）。我们发现，素食儿童的 c-OC 与调整总能量摄入（植物蛋白、磷、镁和纤维摄入量）后的营养参数呈正相关。
食用素食的青春期前儿童的总骨密度和腰椎骨密度 z 评分显著降低，但骨矿物质密度的绝对值没有差异。骨密度 z 评分与骨代谢标志物和营养变量无关，但与人体测量参数呈正相关。素食儿童的瘦素水平较低，反映出体脂较低。需要进行纵向研究来评估所观察到的相关性对成年期骨骼健康的影响。
