HYPERHOMOCYSTEINEMIA AND THE RESPONSE TO VITAMIN SUPPLEMENTATION

The long-term vitamin requirements of men (n=22) with moderate hyperho mocysteinemia (plasma total homocysteine concentration > 16.3 mumol/l) were investigated over a period of 48 weeks. An initial 6-week period of vitamin supplementation (1.0 mg folic acid, 10 mg pyridoxine, 0.05 mg cyanocobalamin) reduced plasma homocysteine levels 54.7% (P<0.001) . However, 18 weeks after vitamin therapy was discontinued, only seven participants (subgroup A) still had plasma homocysteine levels of 16. 3 mumol/l or lower. The remainder of the participants (subgroup B) req uired a second 6-week period of vitamin therapy to normalize the eleva ted plasma homocysteine levels. Substitution of vitamin supplementatio n by dietary guidelines to increase folate intake from food products f ailed to maintain normal plasma homocysteine levels in participants fr om subgroup B. Long-term vitamin supplementation may be required in so me individuals to prevent hyperhomocysteinemia.