Dietary and supplementary betaine: acute effects on plasma betaine and homocysteine concentrations under standard and postmethionine load conditions in healthy male subjects.

BACKGROUND Betaine comes from the diet and from choline, and it is associated with vascular disease in some patient groups. Betaine supplementation lowers plasma total homocysteine. OBJECTIVE We compared the acute effects of dietary and supplementary betaine and choline on plasma betaine and homocysteine under standard conditions and after a methionine load. DESIGN In a randomized crossover study, 8 healthy men (19-40 y) consumed a betaine supplement (approximately 500 mg), high-betaine meal (approximately 517 mg), choline supplement (500 mg), high-choline meal (approximately 564 mg), high-betaine and -choline meal (approximately 517 mg betaine, approximately 622 mg choline), or a low-betaine and -choline control meal under standard conditions or postmethionine load. Plasma betaine, dimethylglycine, and homocysteine concentrations were measured hourly for 8 h and at 24 h after treatment. RESULTS Dietary and supplementary betaine raised plasma betaine concentrations relative to control (P < 0.001) under standard conditions. This was not associated with raised plasma dimethylglycine concentration, and no significant betaine appeared in the urine. A small increase in dimethylglycine excretion was observed when either betaine or choline was supplied (P = 0.011 and < 0.001). Small decreases in plasma homocysteine 6 h after ingestion under standard conditions (P < or = 0.05) were detected after a high-betaine meal and after a high-betaine and high-choline meal. Dietary betaine and choline and betaine supplementation attenuated the increase in plasma homocysteine at both 4 and 6 h after a methionine load (P < or = 0.001). CONCLUSIONS Dietary betaine and supplementary betaine acutely increase plasma betaine, and they and choline attenuate the postmethionine load rise in homocysteine concentrations.