Effect of catfish and salmon diet on platelet phospholipid and blood clotting in healthy men Casimir C. Akoh and James O. Hearnsberger Department of Food Science and Technology, Mississippi State University, Mississippi State, MS, USA The effect of diets containing either catfish or salmon fish on blood clotting and platelet phospholipid fatty acid composition was studied in 17 healthy, young men. The subjects received a control diet for 21 days followed by either catfish diets (n = 9) or salmon diets (n = 8)for an additional 19 days. Catfish and salmon diets prolonged the subjects' bleeding times (by 66% and 57%, respectively) and clotting times (by 25% and 31%, respectively), P < 0.05. The platelet count in catfish and salmon groups decreased by 7% and 9%, respectively. There were no differences in the prothrombin time (PT) and activated partial thromboplastin time (APTT). A small but significant increase (P < 0.05) in fibrinogen concentration was observed in catfish (243.7 mg/dL) and salmon diet groups (246.5 mg/dL) compared to the control group (223.9 mg/dL). Diets containing catfish and salmon led to significant incorporation of total n-3 polyunsaturated fatty acids, PUFAs (from 5.04% on the control to 6.14% and 10.26%, respectively) and total EPA + DHA (from 3.77% on the control to 4.84% and 8.83%, respectively). The n-3/n-6 ratio increased in both groups while the ratio of 20:5/20:4 increased only in the salmon group from 0.05 on the control diet to 0.14. The reduction in arachidonic acid (20:4 n-6) and total n-6 PUFAs was not statistically significant in the catfish group but was significant in the salmon group. The findings suggest that there were minor differences between hemostatic parame- ters in men fed catfish and salmon. The consumption of either diet led to incorporation of dietary n-3 PUFAs into platelet phospholipids, and may result in alteration in platelet and hemostatic filnction in men. Keywords: catfish; salmon; blood clotting; phospholipid Introduction It has been suggested that the n-3 polyunsaturated fatty acids (PUFAs) found in marine fish and fish oils might help prevent cardiovascular disorders, result in increased amounts of n-3 PUFAs and decreased amounts of n-6 PUFAs in the serum, and increased bleeding times. 1-8 It was proposed that large quantities of n-3 PUFAs, mainly eicosapentaenoic acid (EPA), in the diet protects Eskimos against thrombotic car- diovascular disorders.l'2 Their intake of monounsatu- Address reprint requests to Dr. Casimir C. Akoh, at his present address: Department of Food Science and Animal Industries, P.O. Box 264, Alabama A&M University, Normal, AL 35762, USA. This study was supported in part by a grant from the U.S. Depart- ment of Agriculture, USDA, Project No. 0813-350. Received July 16, 1990; accepted December 27, 1990. rated and n-3 PUFAs is high and that of linoleic and arachidonic acids is low. Both their plasma and plate- let lipids have similar fatty acid profiles to that present in their diet. EPA (C20 : 5 n-3) appears to be important among the dietary fatty acids because of its potent antiaggregatory effects. 1'7 It has been suggested that C20:5 in the platelets is converted by the vascular wall tissue to an anti-aggregatory prostacyclin, and may have antithrombotic influence on hemostasis and thrombosis. 2 The antithrombotic influence produced by an altered prostaglandin substrate pool may pro- long the bleeding time by reducing platelet aggre- gation. The results of intervention studies on other indices of coagulation, such as platelet number, prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen concentration are inconsis- tent/ Changing the dietary fatty acids to resemble those taken by Greenland Eskimos may help the West- © 1991 Butterworth-Heinemann J. Nutr. Biochem., 1991, vol. 2, June 329