[高同型半胱氨酸血症的营养决定因素]

Krajcovicová-Kudlácková M, Blazícek P

Ustav preventívnej a klinickej medicíny, Bratislava Nemocnica Ministerstva obrany, Bratislava.

Cas Lek Cesk. 2002 Jul;141(13):417-20.

BACKGROUND

Vitamin B12, folate and vitamin B6 are the main determinants of homocysteinemia. These B-group vitamins influence two metabolic pathways of homocysteine reduction, which prevail in dependence to methionine intake. Transsulfuration (vitamin B6) dominates under condition of overnutrition with prevalence of animal food sources, remethylation (vitamin B12 and folic acid) is decisive under conditions of malnutrition, alternative nutrition or optimal traditional diet.

METHODS AND RESULTS

Plasma homocysteine and folic acid, vitamins B12 and B6 in serum were measured in alternative nutrition groups of adults (vegans, vegetarians (lacto + lactoovo), semivegetarians, n = 39) and compared with those values in group consuming traditional diet--control group, general population (n = 35). In alternative nutrition groups, the average homocysteine level is significantly higher (vegans 17.2 mumol/l, vegetarians 12.9 mumol/l, semivegetarians 10.1 mumol/l, control group 9.9 mumol/l); the frequency of hyperhomocysteinemia (over 15 mumol/l) is 50%, 32%, 14% vs. 6% in control group. Vegetarians and vegans have a significantly higher levels of vitamin B6 and folic acid; the frequency of vitamin B6 deficit is 60% and 57% in control group and semivegetarian group vs. 16% and 0% in vegetarian and vegan group. Folate deficit was found in 16% of traditional group vs. 0% in alternative groups. Serum levels of vitamin B12 are significantly reduced in subjects consuming alternative nutrition with deficiency observed in 67% of vegans, 32% of vegetarians, 14% of semivegetarians vs. 0% in control group.

CONCLUSIONS

Vitamin levels in relation to nutritional regime and metabolic pathways of homocysteine show that the mild hyperhomocysteinemia in alternative nutrition is a consequence of vitamin B12 deficiency. In traditionally fed population, higher plasma homocysteine values is caused by folate deficiency. These conclusions are supported by a significantly negative linear correlation of homocysteine--folic acid levels (traditional nutrition) and homocysteine--vitamin B12 levels (alternative nutrition). In case of vitamin B6, a similar correlation was not found.

背景

维生素B12、叶酸和维生素B6是高同型半胱氨酸血症的主要决定因素。这些B族维生素影响同型半胱氨酸还原的两条代谢途径，这两条途径在很大程度上取决于蛋氨酸的摄入量。在以动物源性食物为主的营养过剩情况下，转硫途径（维生素B6）占主导地位；在营养不良、替代饮食或传统最佳饮食情况下，再甲基化途径（维生素B12和叶酸）起决定性作用。

方法与结果

对成人替代饮食组（纯素食者、素食者（乳类+乳蛋类）、半素食者，n = 39）的血浆同型半胱氨酸、血清叶酸、维生素B12和维生素B6进行检测，并与食用传统饮食的对照组（普通人群，n = 35）进行比较。在替代饮食组中，平均同型半胱氨酸水平显著较高（纯素食者17.2μmol/L，素食者12.9μmol/L，半素食者10.1μmol/L，对照组9.9μmol/L）；高同型半胱氨酸血症（超过15μmol/L）的发生率分别为50%、32%、14%，而对照组为6%。素食者和纯素食者的维生素B6和叶酸水平显著较高；对照组和半素食组维生素B6缺乏的发生率分别为60%和57%，而素食组和纯素食组分别为16%和0%。传统饮食组中16%的人叶酸缺乏，而替代饮食组中这一比例为0%。食用替代饮食的受试者血清维生素B12水平显著降低，纯素食者中67%、素食者中32%、半素食者中14%存在缺乏，而对照组中这一比例为0%。

结论

与营养状况和同型半胱氨酸代谢途径相关的维生素水平表明，替代饮食中轻度高同型半胱氨酸血症是维生素B12缺乏的结果。在传统饮食人群中，较高的血浆同型半胱氨酸值是由叶酸缺乏引起的。同型半胱氨酸与叶酸水平（传统营养）以及同型半胱氨酸与维生素B12水平（替代营养）之间显著的负线性相关性支持了这些结论。对于维生素B6，未发现类似的相关性。