Postprandial leukocyte increase in healthy subjects.

Atherosclerosis is an inflammatory disorder involving leukocytes and lipids. To study the relationship between leukocytes and lipids in vivo, leukocyte changes were determined in 14 healthy males (age, 23 +/- 3 years; body mass index [BMI], 21.9 +/- 1.5 kg/m(2)) after an 8-hour oral fat load (50 g/m(2)) and after water. The postprandial triglyceride (TG) increment after fat was paralleled by a leukocyte increment, due to an increase in neutrophils in the first 2 hours (142% +/- 69% higher than baseline, P =.04). Neutrophil counts did not return to baseline at the end of the test. Water ingestion did not induce significant neutrophil changes. Blood lymphocytes increased gradually in both tests (142% +/- 30% higher than baseline, P <.001 after fat, and 128% +/- 36%, P =.02 after water). The total leukocyte increment after fat ingestion was related to the postprandial TG increase (Spearman's r = 0.73, P =.003). An early postprandial, lipid-specific, neutrophil increment is a new characteristic of the postprandial phase. Future studies will elucidate the role of postprandial leukocyte changes in the pathogenesis of atherosclerosis.