G80A reduced folate carrier SNP influences the absorption and cellular translocation of dietary folate and its association with blood pressure in an elderly population

Abstract

The functional consequences of the G80A RFC SNP on the expressed reduced folate carrier protein were evaluated by looking at the relationship between intake of folate, plasma folate and cellular stores of the vitamin. The effect on homocysteine was also examined. Homocysteine is a thiol that is known to be inversely associated with folate, and which is considered to be both thrombo- and athrogenic. At high levels, homocysteine may also interfere with nitric oxide mediated vasodilation, cause oxidative injury to, and proliferation of the vascular endothelium, and alter the elastic properties of the vascular wall, contributing to increased blood pressure. Participants (119; 52 male, 67 female) from a NSW retirement village were assessed. Independent of gender, the assimilation of folate from dietary sources into red cells showed a significant association for GG (r=0.399; p=0.022) and GA (r=0.564; p<0.0001) subjects, but not homozygous recessive (AA) individuals (r=0.223; p=0.236). The same genotype based pattern of significance was shown for the association between dietary folate and plasma folate (GG: r=0.524; p=0.002, GA: r=0.408; p=0.002). No genotype-related pattern of significance was shown for the association between dietary folate and homocysteine. When examined by gender, some differences were apparent; one-way ANOVA showed that genotype influenced diastolic blood pressure in males (p=0.019), while only females showed a significant correlation between dietary folate and blood pressure within specific genotypes (Systolic pressure GA: r=-0.372; p=0.025, carriage of A: r=0.-0.357; p=0.011. Diastolic pressure GA: r=-0.355; p=0.034, carriage of A: r=0.-0.310; p=0.029). The G80A RFC SNP had an impact on the absorption and cellular translocation of dietary folate and its association with blood pressure in an elderly population.