Influence of long-term diet modification on platelet function and composition in Moselle farmers.

Platelet function and composition, lipemia, and dietary habits were evaluated yearly in 98 male farmers from Moselle (East of France) before and after decreasing, in half of them, dietary saturated fats from 16.2% to 9.9% of calories (P/S from 0.32 to 0.97). One year after these dietary changes, cholesterol and triglycerides decreased by approximately 10%, platelet aggregation to thrombin by 81%, and their clotting activity by 30%. However, ADP aggregation was enhanced by 54%. At 2 yr the P/S was decreased to 0.7 and diet also modified in controls, with 18:2 being increased mostly in one group (P/S = 0.81) and 18:3 in another (P/S = 0.59). In both groups, the main platelet function tests were significantly depressed 1 yr later. Considering the whole study, the intake of saturated fat was mostly correlated (group and individual) with platelet aggregation to thrombin, platelet clotting activity, and 20:3 (n-9) in plasma and platelet lipids.

Effect of smoking and dietary saturated fats on platelet functions in Scottish farmers.

Coagulation and platelet aggregation to thrombin and adrenaline, before and 10 min after smoking one high nicotine cigarette, were studied in 40 healthy male farmers (40 to 45 years) from the South-West and North-East of Scotland. These tests were conducted in association with detailed dietary studies. In the West group the intake of dairy fats, saturated fats and P/S ratio as well as most of the platelet function tests estimated were significantly higher than in the East group. Serum cholesterol (total and HDL) was similar in the two regions, while triglycerides were lower in the West. Smoking one cigarette considerably enhanced the platelet functions in both areas but the increases were more marked in the West group. The increase in the response of platelets to smoking was additive to that apparently induced by the intake of saturated fat in such a way the response of platelets to thrombin and epinephrine after smoking one cigarette in the West was approximately four times this obtained before smoking (or in a non-smoker) in the East. These additive effects of cigarette and saturated fat might be relevant to the reported higher incidence of coronary heart disease in the West of Scotland.

Dietary fats and platelet function in French and Scottish farmers.

Although the intake of saturated facts still appears to be the environmental factor most closely associated with coronary heart disease (CHD), this does not necessarily mean that CHD is caused essentially or solely by blood lipids, as suggested by several investigators. It seems that blood platelets rather than (or at least in addition to) blood lipids might be the intermediate link between certain environmental factors (saturated fats, hard water) and CHD, through an effect on both thrombosis and atherosclerosis. Our recent studies in French and Scottish farmers, have shown that blood platelet function is more drastically affected by saturated fats than blood lipids. In those studies, platelet function was the only blood parameter correlated on an individual basis with the intake of saturated fat and inversely related to calcium intake. Calcium is probably the cation responsible for the protective effect of hard water against CHD in various countries. The results obtained also indicate that platelet function can be improved by increasing the intake of polyunsaturated fats at the expense of saturated fats. Finally, only platelet function was different from one region of France to another and from our region of Scotland to another; this difference could be related to the reported incidence of CHD in these various regions.