Diet Rich in Saturated Fat Decreases the Ratio of Thromboxane/prostacyclin in Healthy Men

Objective: To investigate the effect of dietary saturated fat (SFA) from animal sources on the urine excretion 11-dehydro thromboxane B₂ (TXB₂) and 6-keto prostaglandin F 1α (PGF 1α) in 27 healthy free-living male subjects aged 30 to 55 years. Methods: It was a randomized crossover design. Each volunteer was randomly assigned to one of the two diets (high fat and low fat) for a period of 4 weeks, after which each subject resumed his usual diet for 2 weeks as a 'wash-out period', before being assigned to the other diet for an additional 4 weeks. Results: Serum proportion of 20:4n-6 was 5% lower in the high fat (6.2% of total fatty acid) than in the low fat diet (6.5% of total fatty acid), which was associated with a significantly decreased ratio of the urinary excretion 11-dehydro TXB ₂ to 6-keto PGF 1α (P<0.05). However, there was no significant fall in the absolute urinary excretion of 11-dehydro TXB ₂. Conclusions: Diet rich in SFA from animal sources may influence TXA₂ formation via effect on tissue proportion of 20:4n-6.