Effects of gamma-glutamyl carboxylase gene polymorphism (R325Q) on the association between dietary vitamin K intake and gamma-carboxylation of osteocalcin in young adults.
BACKGROUND
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.
Division of Nutrition, Department of Food and Nutrition, Faculty of Human Sciences and Design, Japan Women's University 2-8-1, Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan. goseki@fc.jwu.ac.jp.
Mayu
M
Haraikawa
Naoko
N
Tsugawa
Natsuko
N
Sogabe
Rieko
R
Tanabe
Yuka
Y
Kawamura
Toshio
T
Okano
Takayuki
T
Hosoi
Masae
M
Goseki-Sone
D019735:Carbon-Carbon Ligases / Q000235:genetics* / Q000378:metabolism*; D004032:Diet; D005838:Genotype; D006801:Humans; D007564:Japan; D008297:Male; D009752:Nutritional Status; D015675:Osteocalcin / Q000097:blood*; D020641:Polymorphism, Single Nucleotide; D045730:Soy Foods / Q000032:analysis; D014812:Vitamin K / Q000008:administration & dosage*; D010837:Vitamin K 1 / Q000097:blood; D024482:Vitamin K 2 / Q000031:analogs & derivatives / Q000097:blood; D014813:Vitamin K Deficiency / Q000235:genetics; D055815:Young Adult
D015675:Osteocalcin; D024482:Vitamin K 2; D014812:Vitamin K; D010837:Vitamin K 1; C062629:menaquinone 7; D019735:Carbon-Carbon Ligases; C020660:glutamyl carboxylase