Possible Interaction: Homocysteine and Vitamin C

“GTN-induced endothelium independent brachial artery dilatation was not affected after methionine or methionine preceded by vitamin C. CONCLUSIONS We conclude that an elevation in homocysteine concentration is associated with an acute impairment of vascular endothelial function that can be prevented by pretreatment with vitamin C in healthy subjects.”

“Hence, a daily tablet of vitamin C may enable community prophylaxis against the disease-but homocysteine status would need monitoring.”

“At pH 7.4, an ascorbic acid concentration at least as high as the concentration of homocysteine might be necessary to efficiently inhibit LDL oxidation by iron(III) and copper(II) in the presence of homocysteine and cystine.”

“Multiple regression showed a negative linear correlation of homocysteine and folic acid, vitamin B12 (determinants of homocysteine metabolism), vitamin C (antioxidative effect) together (n=265, r=-0.282, p<0.00008).”

“Interestingly, Chambers et al. recently demonstrated that an acute elevation in homocysteine concentration is associated with rapid onset endothelial dysfunction which can be prevented by pretreatment with the antioxidant vitamin C [9].”

“Intakes of folate, vitamin C , and fruits and vegetables were inversely associated with tHcy , as were serum folate and vitamin B12 (Spearman's rho, -0.2 to 0.4; P<.05).”

“Concomitant administration of vitamin C significantly prevented these alterations caused by homocysteine.”

“The antioxidant ascorbic acid prevented the effect of HCY on arginine transport.”

“These observations, together with that of rapid non-enzymatic reduction of dehydroascorbic acid by homocysteine3, suggested that ascorbic acid catalyses the oxidation of homocysteine in vivo, and that homocysteic acid is a precursor of the esterified sulphate of connective tissue proteoglycans.”

“Enzyme studies indicate that low ascorbic acid levels added in vitro reduce liver choline oxidase activity in the presence of homocysteine whereas higher levels stimulate activity of the enzyme system.”