PLASMA FACTOR-VII IS ACTIVATED BY POSTPRANDIAL TRIGLYCERIDEMIA, IRRESPECTIVE OF DIETARY-FAT COMPOSITION

Nine adults took two 7-day diets of standardised energy and total fat content, but with a dietary polyunsaturated/saturated fat ratio of < 0.3 and > 3.0 respectively, while adhering to their daily routine. Blood was drawn on 6 occasions between 09.00 and 22.45 h on the final day of each dietary period for factor VII activity (VII(c)), factor VII antigen (VII(ag)) and lipoprotein lipid concentrations. Diurnal variation was described for each variable in terms of its deviation from the individual's daily mean value at each time point across the day. Plasma triglyceride remained low until after the midday meal, whereafter a marked rise was sustained into the later evening. Plasma VII(c) declined until early afternoon, but showed a marked rise in the late afternoon. Plasma VII(ag) showed no significant diurnal variation. Changes in plasma triglyceride concentration during the day were related positively to changes in VII(c) about 160 min later, but not to VII(c) at other time points. This effect of postprandial triglyceridaemia on VII(c) persisted after allowance for the effect of VII(ag) on VII(c). Dietary fat composition did not influence VII(c) or VII(ag). The results suggested an acute but evanescent effect of triglyceride-rich lipoproteins on the reactivity of factor VII, irrespective of their lipid core composition.