Nutritional Aspects of Fish Compared with Other Protein Sources

This article presents an overview of the consumption rates and nutritional benefits of eating fish. While its specific contributions to the nutritional quality of the diet depend upon the amount of fish (versus other foods) and species (fatty versus lean) consumed, it is most valued as a ‘‘protein food.’’ The Biological Value and Protein Efficiency Ratio, indices of the amino acid profile and ability to support growth, are higher for fish than for beef, pork, chicken, and milk proteins. In addition, the types and proportions of dietary fats are generally more ‘‘heart healthy’’ than the fats found in other protein foods. Approximately 50% of the fatty acids in lean fish (e.g., walleye and yellow perch) and 25% in fattier fish (e.g., channel catfish and rainbow trout) are polyunsaturated fatty acids. The amount of saturated fatty acids, associated with increased risk of heart disease, tends to be relatively constant across fish species, at about 25% (Sabry, 1990). In contrast, the polyunsaturated and saturated fatty acids in beef are 4–10% and 40–45%, respectively, of the total fatty acids present. Fish also is valued as a source of omega-3 (n-3) fatty acids, very longchain polyunsaturated fatty acids that are critical for the development of the brain and retina and that may be protective of some chronic diseases. Eicosapentanoic acid (EPA) (20:5 n-3) and docosahexanoic acid (DHA) (22:6 n-3), which account for approximately 90% of the polyunsaturated fatty acids in fish species from the North Atlantic and North Pacific (Sabry, 1990), are absent or present in much lower amounts in other foods. The amount of cholesterol found in fish is comparable to levels in beef, pork, and