Alfthan Georg, Tapani Kaisa, Nissinen Katja, Saarela Janna, Aro Antti
Department of Health and Functional Capacity, National Public Health Institute (KTL), Helsinki, Finland.
Br J Nutr. 2004 Oct;92(4):665-9. doi: 10.1079/bjn20041253.
Homocysteine is a risk factor for vascular diseases, and lowering of plasma total homocysteine (tHcy) may be beneficial for health. Homocysteine can be remethylated to methionine by betaine-homocysteine methyltransferase using betaine (2(N,N,N-trimethyl)glycine) as methyl donor. A dose of 6 g betaine/d has been used in the treatment of homocystinuria, but data on the dose-response are scarce. Thirty-four healthy men and women were supplied with doses of 1, 3 and 6 g betaine and then with 6 g betaine+1 mg folic acid for four consecutive 1-week periods. The mean plasma tHcy concentration decreased by 1.1 (NS), 10.0 and 14.0 % (P<0.001) after supplementation with 1, 3 and 6 g betaine respectively. A further decrease in plasma tHcy by 5 % (P<0.01) was achieved by combining 1 mg folic acid with the 6 g betaine dose. Plasma betaine increased from 31 (sd 13) to 255 (sd 136) mumol/l in a dose-dependent manner (R(2) 0.97). We conclude that plasma tHcy is lowered rapidly and significantly by 3 or 6 g betaine/d in healthy men and women.
同型半胱氨酸是血管疾病的一个风险因素，降低血浆总同型半胱氨酸（tHcy）可能对健康有益。同型半胱氨酸可通过甜菜碱-同型半胱氨酸甲基转移酶以甜菜碱（2（N，N，N-三甲基）甘氨酸）作为甲基供体重新甲基化生成蛋氨酸。6克/天的甜菜碱剂量已用于治疗同型胱氨酸尿症，但关于剂量反应的数据很少。34名健康男性和女性连续4个为期1周的时间段分别服用1克、3克和6克甜菜碱，然后服用6克甜菜碱 + 1毫克叶酸。补充1克、3克和6克甜菜碱后，血浆tHcy平均浓度分别下降了1.1%（无统计学意义）、10.0%和14.0%（P<0.001）。6克甜菜碱剂量与1毫克叶酸联合使用使血浆tHcy进一步下降了5%（P<0.01）。血浆甜菜碱以剂量依赖性方式从31（标准差13）微摩尔/升增加到255（标准差136）微摩尔/升（R² 0.97）。我们得出结论，健康男性和女性每天服用3克或6克甜菜碱可迅速且显著降低血浆tHcy。
