Influence of dietary fat ingestion on asymmetrical dimethylarginine in lean and obese human subjects.

Background And Aims: Asymmetrical dimethylarginine (ADMA) may contribute to hypertension and cardiovascular disease by decreasing NO formation. In diabetic patients, a high fat meal acutely increased plasma ADMA while impairing endothelial function. We hypothesized that chronic and acute increases in dietary fat intake augment ADMA also in lean and in obese subjects without diabetes.

Methods And Results: Seventeen lean and twelve obese volunteers were randomized to two weeks of isocaloric diets with approximately 20% or >40% calories from fat in a cross-over fashion. At the end of the high and low fat periods, volunteers received corresponding test meals. ADMA was measured by GC-MS/MS using a deuterated standard. Mean fasting plasma ADMA concentration was 0.52 (0.49-0.54; 95% CI) μmol/l in lean and 0.53 (0.50-0.55) μmol/l in obese subjects (p = 0.55). The two week high fat diet did not influence ADMA. Both test meals elicited a 6%increase in circulating ADMA in lean subjects. In obese subjects, plasma ADMA concentration did not change with the low fat meal, and decreased by approximately 4% with the high fat meal.

Conclusion: Our findings challenge the idea that obesity and dietary fat intake have a major effect on plasma ADMA, at least in subjects without overt cardiovascular and metabolic disease. This finding is important with regard to dietary recommendations for weight loss. Overestimation of the influence of dietary fat intake and obesity on circulating ADMA in previous reports was most likely due to methodological issues concerning ADMA measurements.