Elevated total plasma homocysteine (HC) has been identified recently as a modifiable risk factor for cardiovascular disease. Because both betaine (BET) and exercise are associated with reduced HC, these benefits may be cumulative.
To examine the influence of acute betaine intake on exercise-related changes in homocysteine, glucose, and lipid levels, in the physiological context of exercise in the heat.
Ten male runners (mean±SE age,20.1±0.6y;height,177±2.0cm;mass,70.6±2.2kg;body fat,6.2±0.7%;VO2peak,63.5±1.3ml·kg−1·min−1) dehydrated to −2.7±0.1%BW via overnight food and water restriction, then performed morning exercise. During a 45 min recovery, subjects consumed 1L of a 6% carbohydrate-containing fluid electrolyte beverage(C), C+5g betaine(C+B), a placebo beverage(P) or P+5g betaine(P+B). Thereafter, a 75 min performance run (65%VO2peak;31.1±0.1°C;34.8±0.8%RH) preceded a final sprint at 90%VO2peak to exhaustion.
In the betaine trials, HC was lower 15 min post-sprint (C+B 6.9±0.6 and P+B 7.3±0.7 μmol·l−1) than the placebo trials (C 7.4±0.5 and P 7.4±0.6 μmol·l−1), although only C+B was significantly lower(P<0.05). Folate and HC were negatively correlated at pre-dehydration in all trials(P<0.05) and at 15 min post-sprint in placebo trials(P<0.05). In all trials, HC decreased during exercise and then increased by 15 min post-sprint(P<0.05), total cholesterol and triglycerides increased over time(P<0.05), and folate increased over time(P<0.05, except in C). In the C+B trial, low-density lipoproteins (LDL) decreased significantly from pre-dehydration to 15 min post-sprint (101.9±6.8 to 98.1±7.2 mmol·l−1,P<0.05). Glucose increased over time but was statistically similar across trials(P>0.05).
We found HC and LDL were significantly lower after exercise in the C+B trial. Addition of betaine to sport drinks for consumption during exercise may increase the HC-lowering effects of exercise. Further, C may potentiate these effects.