Seafood contributes a variety of nutrients to the American diet, including protein and important micronutrients, and its eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content distinguishes it as providing a unique nutritional benefit. EPA and DHA are abundant in some seafood types and the conversion from alpha-linolenic acid (ALA) is inefficient in humans (Burdge, 2004). Seafood is not a primary source for ALA. EPA and DHA are believed to be important in reducing the risk of cardiovascular disease, lengthening gestation, and possibly promoting fetal and infant neurological development. For these reasons, several groups have recommended inclusion of seafood, particularly those choices high in EPA/DHA, in the American diet (see Appendix Table B-3). These recommendations frequently refer to servings per week; throughout this report, unless otherwise stated, a serving of seafood is defined as 4 ounces raw, which yields 3 ounces cooked. As noted later in this chapter and throughout the report, some federal and state agencies and nonfederal organizations include larger (8 ounce) serving sizes in their recommendations and advisories. This committee has adopted the convention of the Dietary Guidelines Advisory Committee (see below) in considering a serving size from the meat, poultry, fish, and egg food group to be 4 ounces raw, or 3 ounces cooked.
Every 5 years, an expert Dietary Guidelines Advisory Committee (DGAC) is appointed to make recommendations to the Secretaries of the Department of Health and Human Services (HHS) and the Department of Agriculture (USDA) concerning revision of the Dietary Guidelines for Americans (DGA). In 2005, the DGAC issued its own report, separate from the Dietary Guidelines, which reviewed the preponderance of scientific and medical knowledge and suggested a set of key messages (DGAC, 2005).
One of these messages, in the section on dietary fats, was “the consumption of two servings (approximately 6–8 ounces) per week of fish high in EPA and DHA is associated with reduced risk of both sudden death and death from coronary heart disease in adults. To benefit from the potential cardioprotective effects of EPA and DHA, the weekly consumption of two servings of fish, particularly fish rich in EPA and DHA, is suggested. Other sources of EPA and DHA may provide similar benefits; however, further research is warranted.” The strength of this message was tempered somewhat by the section on food safety, which warned of the potential danger of methylmercury in fish.