Nutrients, platelet function and composition in nine groups of French and British farmers.

In 260 male farmers (40-45 years) divided into 9 groups from different areas in France and Britain, coagulation, platelet aggregation, lipemia, fatty acids from plasma lipids and platelet phospholipids were determined in relation to the food intake evaluated by recall, weighing and chemical analysis of the diet. The clotting activity of platelets and their response to thrombin aggregation was significantly correlated on an individual basis with the intake of saturated fatty acids both in subsamples as well as in the whole study. Serum cholesterol was also significantly correlated with saturated fats but only on a group basis or on the totality of the study. Calcium, linolenic acid and alcohol in the diet were inversely related to certain platelet functions. Linoleic acid was inversely related to serum cholesterol and triglycerides. Dietary saturated fats were associated, with an increase in the platelet phospholipids not in saturated fatty acids but in 20:3 (n-9), known to promote platelet aggregation to thrombin, with a decrease in platelet cholesterol, also apparently regulating platelet functions. The present studies indicate that dietary saturated fats, calcium (hard water) and alcohol, influence platelet behaviour in a way strictly parallel to their known effect on coronary heart disease.

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.

Platelet functions in relation to diet and serum lipids in British farmers.

Coagulation and platelet aggregation induced by thrombin, ADP, adrenaline, and collagen were studied in three contrasted groups, each of 20 to 22 middle-aged male farmers. Serum lipids were similar in the three groups. In the west of Scotland group, however, platelet reactivity was significantly greater than in the east of Scotland. This was associated with a dietary intake, evaluated by three different techniques, higher in saturated fat but also lower in polyunsaturated fat and alcohol. Platelet function in the southern England group also correlated with dietary fats and in addition inversely with calcium intake. On an individual basis in the 63 farmers, all the platelet function tests were significantly correlated with the intake of saturated fat regulated by that of calcium and alcohol. The dietary effects on platelets appear to be mediated by the fatty acid composition of plasma lipids and of platelet phospholipids. In that fraction, the fatty acids 20:3 omega 9, 22:3 omega 9 and 20:4 were the most closely related to the platelet function tests. the trienoic acid 20:3 omega 9, identified with essential fatty acid deficiency, was also correlated with the intake of saturated fat and calcium. In this study, platelet functions were more dependent upon the dietary factors associated with coronary heart disease such as saturated fats, calcium, and alcohol than upon serum lipids.

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.

Platelet functions in relation to dietary fats in farmers from two regions of France.

To determine whether the long-term feeding of dietary fats affect platelet functions in man, platelet aggregation (to thrombin ADP, collagen, epinephrine) and clotting activity of platelet-rich plasma (PRP), platelet-poor plasma and of washed platelets were studied in a mobile-laboratory in 44 healthy male farmers (40--45 years) from two French regions Var and Moselle, in relation to lipemia, glycemia, dietary nutriments, and platelet phospholipid composition. In the Moselle subjects, the platelet clotting activity of PRP and of washed platelets, the platelet aggregation to thrombin and ADP, were highly significantly (p less than 0.001) increased as compared to those of Var, but not the plasma cholesterol, which was identical in the two regions. In Moselle, the intake of total calories, total lipids and saturated fats was higher than in the Var. However, it was only with the saturated fat intake (mostly stearic acid) that the platelet clotting activity (p less than 0.01) and the platelet aggregation (p less than 0.001) were highly significantly correlated. The platelet clotting activity was also significantly (p less than 0.001) correlated with the fatty acid composition of the platelet phospholipid fractions phosphatidyl serine + phosphatidyl inositol.