Introduction: It has been demonstrated that single nucleotide polymorphism (SNP) (R325Q, 974G>A) in the gamma-glutamyl carboxylase (GGCX) gene is associated with the bone mineral density (BMD). In the present study, we investigated the effect of GGCX polymorphism (974G>A) on the correlations among the vitamin K in-take, level of serum vitamin K, and ratio of undercarboxylated osteocalcin (ucOC) to intact osteocalcin (OC) in healthy young Japanese subjects.
Methods: Healthy young adult subjects (n=189) were genotyped for the poly-morphism, and we measured the levels of serum vitamin K, intact OC, ucOC, and dietary nutrient intakes.
Results: Dietary vitamin K intake from vegetables was significantly correlated with the level of serum phylloquinone (PK), and vitamin K intake from fermented beans, natto, was also significantly correlated with the level of serum menaquinone-7 (MK-7). Moreover, the total dietary vitamin K intake showed a significant negative correlation with the ratio of ucOC to intact OC. Interestingly, on grouping by the GGCX genotype, there was a significant interaction between the ratio of ucOC to intact OC with vitamin K intake in homozygotes (GG-type) and heterozygotes (GA-type) (p<0.001). These results suggest that an adequate nutritional strategy is necessary for people with high-risk genotypes (GG- or GA-type).
Conclusions: We demonstrated the effects of SNP (974G>A) in the GGCX gene on the correlation between dietary vitamin K intake and gamma-carboxylation of serum OC. Our data may be useful for planning strategies to prevent osteoporosis.
前言：γ-麩胺醯羧化酶(GGCX)基因的單核苷酸多型性(SNP)與骨骼礦物質密度 (BMD)之相關性已被證實。本篇研究探討，在日本的健康年輕受試者中，其 GGCX 多型性(974G>A)對於維生素K 攝取、血清中維生素K 濃度和羧化不全骨 鈣素(ucOC)與完整骨鈣素(OC)比值之間關聯性的影響。方法：共有189 位健康 年輕成人進行基因多型性檢測，並測量其血清中維生素K、OC、ucOC 濃度和 飲食中營養素攝取量。結果：飲食中攝取來自蔬菜的維生素K 與血清中維生素 K1(PK；葉綠醌)有顯著相關；而攝取來自發酵豆類-納豆的維生素K 也與血清中 維生素K2(MK-7；甲萘醌-7)有顯著相關。此外，從飲食中攝取的總維生素K 和 ucOC 與OC 比值有顯著負相關。值得注意的是，將GGCX 基因型分組時發現， 同型結合子(GG-type)和異型結合子(GA-type)兩組的ucOC 與OC 比值和維生素 K 攝取有顯著交互作用(p<0.001)。以上結果顯示，適當的營養策略對於具有高 風險基因型(GG-或GA-type)的人是必要的。結論：本研究證實GGCX 基因中的 SNP(974G>A)多型性對於飲食維生素K 攝取與血清骨鈣素γ-羧化相關性之效 應。本資料對於規劃預防骨質疏鬆症之策略也許會有幫助。