Although the precise nutritive value of fish and shellfish varies according to variety and origin, not to mention cooking method, all are good choices for lighter eating. Fish is an excellent source of easily digestible protein and is rich in vitamins and minerals, especially B vitamins, potassium and iodine. Shellfish abound in calcium, phosphorus and magnesium. Researchers have linked consumption of the omega-3 fatty acids found in fish to reduced risk of heart disease and cancer.
Fat content varies by species and even by season, but all fish and shellfish are relatively low in calories. Even high-fat fish contain less fat than most meats, and most of the fat is unsaturated. However, a rich sauce or a dip in melted butter negates the lean profile.