Decreased bioavailability of vitamin D in obesity
Decreased bioavailability of vitamin D in obesity
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DOI：
10.1093/ajcn/72.3.690
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发表时间：
2000-09-01
影响因子：
7.1
通讯作者：
Holick, MF
中科院分区：
文献类型：
--
作者：
Wortsman, J;Matsuoka, LY;Holick, MF
背景：肥胖与维生素D缺乏和继发性甲状旁腺功能亢进症有关。目的：本研究评估肥胖是否会改变皮肤维生素D-3(胆钙醇)的产生或肠道对维生素D-2(麦角钙化醇)的吸收。设计：健康、白人、肥胖[体重指数(BMI；以kg/m(2)为单位)大于或等于30]和匹配的瘦身对照组(BMI小于或等于25)接受全身紫外线照射或口服一定剂量的维生素D。结果：肥胖者的基础25-羟基维生素D浓度显著低于年龄匹配的对照组，甲状旁腺激素浓度高于年龄匹配的对照组。全身照射后24 h的血维生素D-3浓度测定显示，肥胖组维生素D-3增量比非肥胖组低57%，肥胖组和非肥胖组皮肤中维生素D-3前体7-脱氢胆固醇的含量无明显差异，体外照射后维生素D-3前体7-脱氢胆固醇向维生素D-3前体的转化也无明显差异。肥胖和非肥胖受试者口服剂量为50000国际单位(1.25毫克)的维生素D-2。体重指数与照射后血清维生素D-3浓度呈负相关(r=-0.55，P=0.003)，与维生素D-2摄入后血清维生素D-2峰值浓度呈负相关(r=-0.56，P=0.007)。结论：肥胖相关维生素D缺乏可能是由于维生素D-3沉积在体内脂肪隔室，导致皮肤和饮食来源的维生素D-3生物利用度降低所致。
Background: Obesity is associated with vitamin D insufficiency and secondary hyperparathyroidism.Objective: This study assessed whether obesity alters the cutaneous production of vitamin D-3 (cholecalciferol) or the intestinal absorption of vitamin D-2 (ergocalciferol).Design: Healthy, white, obese [body mass index (BMI; in kg/m(2)) greater than or equal to 30] and matched lean control subjects (BMI less than or equal to 25) received either whole-body ultraviolet radiation or a pharmacologic dose of vitamin D-2 orally.Results: Obese subjects had significantly lower basal 25-hydroxyvitamin D concentrations and higher parathyroid hormone concentrations than did age-matched control subjects. Evaluation of blood vitamin D-3 concentrations 24 h after whole-body irradiation showed that the incremental increase in vitamin D-3 was 57% lower in obese than in nonobese subjects, The content of the vitamin D-3 precursor 7-dehydrocholesterol in the skin of obese and nonobese subjects did not differ significantly between groups nor did its conversion to previtamin D-3 after irradiation in vitro. The obese and nonobese subjects received an oral dose of 50 000 IU (1.25 mg) vitamin D-2. BMI was inversely correlated with serum vitamin D-3 concentrations after irradiation (r = -0.55, P = 0.003) and with peak serum vitamin D-2 concentrations after vitamin D-2 intake (r = -0.56, P = 0.007).Conclusions: Obesity-associated vitamin D insufficiency is likely due to the decreased bioavailability of vitamin D-3 from cutaneous and dietary sources because of its deposition in body fat compartments.