目的:二甲双胍是治疗2型糖尿病(DM)的常用一线药物。研究表明,二甲双胍的使用通常与DM患者维生素B12(B12)水平的降低有关。很少有研究表明补充钙可以减轻这种影响。在本研究中,我们量化了二甲双胍的作用,使用新型稳定同位素[13C]氰钴胺示踪剂,二甲双胍与钙共同施用对B12的吸收。
方法:进行了一项试点交叉研究,以评估B12在健康受试者中的生物利用度,使用[13C]氰钴胺作为示踪剂。在研究中,向参与者口服施用[13C]氰钴胺,随后每小时静脉取样以测量示踪剂的浓度并估计生物利用度。按照这个方案进行了三个实验天,每个间隔一个月的清洗期。作为研究的一部分,所有参与者在控制日(C)单独接受示踪剂,二甲双胍850mg以及二甲双胍日示踪剂(M)和二甲双胍850mg以及钙500mg和二甲双胍钙日示踪剂(MC)。
结果:7名参与者完成了所有3天的实验。平均B12生物利用度(±SD,n=7)为对照组(C)的42.6±10.2%,二甲双胍日(M)为30.8±15.3%,二甲双胍钙日(MC)为46.4±8.6%。重复进行方差分析,成对比较显示对照和二甲双胍日的B12生物利用度存在显着差异(CvsMp=0.010),在二甲双胍和二甲双胍钙日之间(MvsMCp=0.003)。
结论:当服用二甲双胍(M)时,B12的生物利用度从基线(C)显着降低,而当在健康参与者中同时服用钙(MC)时,这种降低被逆转。在使用二甲双胍的患者中,补钙作为预防B12缺乏的策略需要进一步研究.
OBJECTIVE: Metformin is a widely prescribed first line drug for the treatment of type 2 diabetes mellitus (DM). Studies have shown that the use of metformin is often associated with a decrease in vitamin B12 (B12) levels in patients with DM. Few studies have shown that this effect could be mitigated with calcium supplementation. In the present
study, we quantified the effect of metformin, and metformin co-administered with calcium on B12 absorption using a novel stable isotope [13C] cyanocobalamin tracer.
METHODS: A pilot crossover
study was conducted to estimate the bioavailability of B12 in healthy subjects, using [13C] cyanocobalamin as a tracer. In the
study, [13C] cyanocobalamin was administered orally to the participants followed by hourly venous sampling to measure the concentration of the tracer and estimate bioavailability. This protocol was followed for three experiment days, each separated by a one month wash out period. As part of the
study, all participants received the tracer alone for the control day (C), metformin 850 mg along with the tracer for the metformin day (M) and metformin 850 mg with calcium 500 mg and the tracer for the metformin calcium day (MC).
RESULTS: Seven participants completed all three experiment days. The mean B12 bioavailability (±SD, n = 7) was 42.6 ± 10.2% for the control day (C), 30.8 ± 15.3% for the metformin day (M) and 46.4 ± 8.6% for the metformin-calcium day (MC). Repeated measures ANOVA was done and the pairwise comparison showed a significant difference in the B12 bioavailability between control and metformin day (C vs M p = 0.010), and between the metformin and metformin with calcium day (M vs MC p = 0.003).
CONCLUSIONS: B12 bioavailability reduced significantly from baseline (C) when metformin (M) was administered and this reduction was reversed when calcium was co-administered (MC) in healthy participants. In patients using metformin, calcium supplementation as a strategy to prevent B12 deficiency needs to be further studied.