RESUMEN
Homocysteine is derived from the metabolic conversion of the essential amino acid methionine. In the remethylation pathway of homocysteine to methionine, vitamin B12 and folate act as cofactors. One of the essential enzymes in the remethylation process is methylenetetrahydrofolate reductase [MTHFR]. Mild-to-moderate hyperhomocysteinemia has been shown to be associated with arterial thrombosis in several case-control and cross-sectional studies. The mechanisms by which hyperhomocysteinemia may predispose to arterial thrombosis are not entirely clear but consist of endothehal cell damage, inhibition of fibrinolysis, activation of the coagulation cascade, impaired generation of nitric oxide and prostacyclin, and enhanced collagen production by smooth muscle cells Major determinants of plasma homocysteine levels are folate, vitamin B12 and B6 intake, renal function, and to a lesser extent cigarette smoking, arterial hypertension, hypercholesterolemia, physical exercise, coffee consumption, and alcohol consumption. In addition, individuals homozygous for the thermolabile form of MTHFR also show higher levels of homocysteine, mainly in the presence of low folate. One further dietary determinant of plasma homocysteine level may be fat intake because fat intake is associated with higher homocysteine levels in healthy men, probably because of a lower intake of essential vitamins. High fat intake has been shown to be linked with childhood obesity, which is associated with an unfavorable profile of risk factors for coronary heart disease [CHD] such as hyperinsulinemia, hyperlipidemia, and elevated blood pressure. Currently no data are available that deal investigate a possible relationship among homocysteine levels, body composition, and metabolic risk factors for coronary heart disease [CHD] in childhood obesity. The aim of the present study was to investigate a possible relationship among plasma homocysteine levels, the methylenetetrahydrofolate reductase [MTHFR] polymorphism, body composition, blood pressure, folate and vitamin B12 levels, serum lipid parameters, and insulin