Betaine supplementation suppresses plasma homocysteine level elevation induced by folate deficiency in rats

The effects of betaine on the plasma homocysteine concentration were investigated in partially folate deficient rats. The rats were fed a test diet containing folic acid at a dose of 8 (control) or 0.5 (low folate) mg/kg. After a 4-week feeding, the plasma homocysteine concentration in the low-folate group increased to 1.6-fold that in the control group. Betaine supplementation (30 g/kg diet) significantly suppressed the plasma homocysteine level elevation and led to an upward trend in liver betaine-homocysteine methyltransferase (BHMT) activity, whereas no change was observed with supplementation with choline (10 g/kg diet), a precursor of betaine. The results of this study suggest that betaine suppresses the plasma homocysteine level elevation induced by low folate intake, and the suppression is associated with the metabolic pathway driven by BHMT.