Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin
Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin
复制标题
DOI：
10.2337/diacare.23.9.1227
复制
发表时间：
2000-09-01
期刊：
影响因子：
16.2
通讯作者：
Herbert, V
中科院分区：
文献类型：
--
作者：
Bauman, WA;Shaw, S;Herbert, V
目的：在服用二甲双胍的患者中，有10-30%的患者有维生素b12吸收减少的证据。已知回肠细胞表面受体对b12内在因子复合物的摄取是一个依赖于钙可用性的过程。二甲双胍影响钙依赖膜的作用。本研究的目的是确定二甲双胍给药后血清维生素B-12减少的幅度和机制。研究设计和方法：采用比较研究设计，分为两组（二甲双胍组和对照组）。共有21例2型糖尿病患者接受磺脲类药物治疗；21例患者中有14例改用二甲双胍。每月测定血清总维生素B-12和全转钴胺素（holoTCII） （B-12- tcii）。二甲双胍治疗3个月后，口服补钙。结果-系列血清维生素B-12测定显示维生素B-12和holoTCII类似的下降。口服补钙逆转二甲双胍诱导的血清holoTCII下降。结论：由于钙依赖性回肠膜拮抗作用，接受二甲双胍治疗的患者B-12吸收减少，血清总维生素B-12和TCII-B-12水平降低，补钙逆转了这一作用。
OBJECTIVE - Of patients who are prescribed metformin, 10-30% have evidence of reduced vitamin B-12 absorption. B-12-intrinsic factor complex uptake by ileal cell surface receptors is known to be a process dependent on calcium availability. Metformin affects calcium-dependent membrane action. The objective of this study was to determine the magnitude and mechanism of the reduction in serum vitamin B-12 after metformin administration.RESEARCH DESIGN AND METHODS - A comparative study design was employed using 2 groups (metformin and control). A total of 21 patients with type 2 diabetes received sulfonylurea therapy; 14 of these 21 patients were switched to metformin. Monthly serum total vitamin B-12 measurements and holotranscobalamin (holoTCII) (B-12-TCII) were performed. After 3 months of metformin therapy, oral calcium supplementation was administered.RESULTS - Serial serum vitamin B-12 determinations revealed a similar decline in vitamin B-12 and holoTCII. Oral calcium supplementation reversed the metformin-induced serum holoTCII depression.CONCLUSIONS - Patients receiving metformin have diminished B-12 absorption and low serum total vitamin B-12 and TCII-B-12 levels because of a calcium-dependent ileal membrane antagonism, an effect reversed with supplemental calcium.