High content of dietary linoleic acid does not reduce platelet reactivity in patients with hyperlipoproteinaemia

Seventeen patients with hypertriglyceridaemia were given a lipid-lowering diet with a high P/S-ratio 2.1 during a 3-week period. The very low density lipoprotein triglycerides decreased by 43%, low density lipoprotein cholesterol by 19% and high density lipoprotein cholesterol by 12%. There was a marked increase of linoleic acid (18:2 n-6) in all plasma lipid esters with a concomitant decrease of the saturated and monounsaturated fatty acids. There was a slight increase of the linoleic acid metabolites 18:3 n-6, 20:3 n-6 and 20:4 n-6 in serum triglycerides whereas the fatty acids of the n-3 series decreased in all plasma lipid esters. In the platelets a similar pattern was found with an increase of linoleic acid and its metabolite 22:4 n-6 and a decrease of 18:1 n-9 as well as of the n-3 fatty acids. No significant differences in platelet reactivity was found. However, in a few patients there was an increased platelet aggregation after the diet period. Our results suggest that this diet based on a very high content of linoleic acid may not affect platelet reactivity in a beneficial way. The reason may be an increased turnover of arachidonic acid in the platelets or an imbalance between the n-6 and n-3 series of fatty acids.