Comparison of the effects of nicotinic acid and nicotinamide degradation on plasma betaine and choline levels.
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, N1-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 N1-methyl-2-pyridone-5-carboxamide during the test period were examined.


RESULTS
The level of 3-h plasma nicotinamide, N1-methylnicotinamide, homocysteine, the urinary excretion of N1-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 < 0.01, except homocysteine and PP P < 0.05), while the 3-h plasma betaine, normetanephrine and metanephrine level in the NM group was 24.4%, 9.4% and 11.7% lower (P < 0.05, except betaine P < 0.01), without significant difference in choline levels. Similar but less pronounced changes were observed in the NA group, with a lower level of 3-h plasma N1-methylnicotinamide (1.90 ± 0.20 μmol/l vs. 3.62 ± 0.27 μmol/l, P < 0.01) and homocysteine (12.85 ± 1.39 μmol/l vs. 18.08 ± 1.02 μmol/l, P < 0.05) but a higher level of betaine (27.44 ± 0.71 μmol/l vs. 23.52 ± 0.61 μmol/l, P < 0.05) than that of the NM group.


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.
['Sun|Wu-Ping|WP|', 'Zhai|Ming-Zhu|MZ|', 'Li|Da|D|', 'Zhou|Yiming|Y|', 'Chen|Na-Na|NN|', 'Guo|Ming|M|', 'Zhou|Shi-Sheng|SS|']
D000328:Adult D001622:Betaine D001794:Blood Pressure D002794:Choline D019587:Dietary Supplements D005527:Food, Fortified D006710:Homocysteine D006801:Humans D006868:Hydrolysis D007700:Kinetics D008297:Male D008676:Metanephrine D008745:Methylation D009525:Niacin D009536:Niacinamide D009647:Normetanephrine D011728:Pyridones D011897:Random Allocation D055815:Young Adult
Nicotinic acid Nicotinamide Betaine Choline Methylation Homocysteine