Addition of 2.5 g L-arginine in a fatty meal prevents the lipemia-induced endothelial dysfunction in healthy volunteers.

BACKGROUND

Endothelial function as determined by flow-mediated dilation (FMD) deteriorates during postprandial lipemia. The impairment can be neutralized by adding 50 g casein to the fatty meal. The objective of this study was to see which of the casein constituents is responsible for this neutralization effect.

DESIGN

A crossover design was used in 15 healthy volunteers, who were given 3 ml cream/kg body weight with and without 2.5 g L-arginine. Lipids and FMD were then determined hourly over a period of 6h. In substudies this design was repeated with 2.5 g phenylalanine and 5 g leucine in 11 subjects. The effect of 2.5 g L-arginine on FMD in the absence of cream was tested in seven subjects.

RESULTS

Without L-arginine the FMD deteriorated during 4h after the fat loading. Addition of L-arginine prevented this deterioration at 3 and 4h. Phenylalanine and leucine, in contrast, did not prevent the lipemic endothelial dysfunction. L-Arginine alone similarly had no acute effect on the FMD.

CONCLUSION

2.5 g L-arginine, but not phenyalanine or leucine, is able to prevent the lipemic dysfunction of the endothelium.