Comparison of the effects of nicotinic acid and nicotinamide degradation on plasma betaine and choline levels.

Summary Aim The present study was to compare the effects of nicotinic acid and nicotinamide on the plasma methyl donors, choline and betaine. Methods Thirty adult subjects were randomly divided into three groups of equal size, and orally received purified water (C group), nicotinic acid (300 mg, NA group) or nicotinamide (300 mg, NM group). Plasma nicotinamide, N 1 -methylnicotinamide, homocysteine, betaine and choline levels before and 1.5-h and 3-h post-dosing, plasma normetanephrine and metanephrine concentrations at 3-h post-dosing, and the urinary excretion of N 1 -methyl-2-pyridone-5-carboxamide during the test period were examined. Results The level of 3-h plasma nicotinamide, N 1 -methylnicotinamide, homocysteine, the urinary excretion of N 1 -methyl-2-pyridone-5-carboxamide and pulse pressure (PP) in the NM group was 221%, 3972%, 61%, 1728% and 21.2% higher than that of the control group ( P P P P N 1 -methylnicotinamide (1.90 ± 0.20 μmol/l vs . 3.62 ± 0.27 μmol/l, P vs . 18.08 ± 1.02 μmol/l, P vs . 23.52 ± 0.61 μmol/l, P Conclusion The degradation of nicotinamide consumes more betaine than that of nicotinic acid at identical doses. This difference should be taken into consideration in niacin fortification.