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 (approximate to 500 mg), high-betaine meal (approximate to 517 mg), choline supplement (500 mg), high-choline meal (approximate to 564 mg), high-betaine and -choline meal (approximate to 517 mg betaine, approximate to 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 <= 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 <= 0.001). Conclusions: Dietary betaine and supplementary betaine acutely increase plasma betaine, and they and choline attenuate the postmethionine load rise in homocysteine concentrations.