Further experiences with blood coagulation after fat meals and carbohydrate meals.

There have been conflicting reports as to whether the ingestion of fat increases the tendency for the blood to clot, and hence, by implication, the risk of thromboembolic complications in man. In this study the effect of a single meal containing a large amount of fat was compared with that of a practically purely carbohydrate isocaloric meal. Under carefully controlled conditions the clotting time varied widely under fasting conditions, and after both fat and carbohydrate meals the clotting time became longer, shorter, or remain unchanged. The results were unpredictable and although a slight trend toward shortened clotting times was evidenced after the fat meals, the results did not reach accepted statistical standards of probability. IN 1949 Duncan and Waldron' reported an acceleration of blood clotting time after the oral administration of fat. An original report from this department2 casts doubt on this finding and it was suggested that the acceleration of clotting may well have been due to deposition of thrombin on the surface of glass syringes when they were reused for successive venipunctures. Then Waldron and Duncan published data that they believed substantiated their original claims.3 Buzina and Keys,4 working with physically healthy men, aged 35 to 60, and using a larger amount of fat, reported a significant shortening of the whole blood coagulation time but no alterations after the ingestion of isocaloric, nonfatty meals. English workers5-12 have reported on different aspects of this problem. Hall5 related clotting variations after a fat meal to platelet preservation and stated that there was no change in blood coagulation when adequate platelet activity was present. Barkhan, Newlands, and Wild6 have isolated from human brain tissue a phospha-tidylethanolamine that they found to be an accelerator of coagulation. O'Brien9 believes that behavior of phosphatidylethanolamine and Hyde Foundations. 936 and platelets is similar. Studying further the effects of eggs and different fats on blood coagulation," he found a shortening of Stypven clotting times 11/2 to 21/2 hours after a meal. There were considerable differences among individuals but no significant differences among different types of fat meals. There is some question whether the Stypven clotting time may actually be measuring the fat in the blood rather than an actual change in the clotting mechanism. MacLagan and Billimoria'2 reported definite shortening of the clotting time after feeding 2 ounces of fat food, the maximal effects taking place 4 to 6 hours after a test meal. Because of …