During the Lenten season, some persons may choose to give up eating meat and consume mainly fish as their main source of protein. Seafood are classified as fish (cod, sardines, mackerel, yellowtail), molluscs (clams, oysters, conch, sea snails), and crustaceans (shrimp, crab and lobsters).
Fish with no added fat (such as margarine, oil, sauces or gravies) is low in fat and is an excellent source of high-quality protein (containing all the essential amino acids).
A high-fat fish such as mullet provides 120 calories, and cod, a low-fat fish, provides 75-80 calories per ounce. The protein content varies, depending on the feeding habits, sex of fish, fat and water content. The flesh of fish with fins contains about 18-22 grams of protein per three ounces. White flesh of fish such as albacore tuna has more protein than the darker flesh fish.
Fish contains mainly unsaturated fatty acids in the form of omega-3 and omega-6 fatty acids. When the fat content in fish is high, the water and protein content is low and when protein and water content is high, the fat content is low. Research has shown that omega-3 fatty acid is needed for growth, reduction in the risk of heart disease by decreasing blood clots, lowering blood pressure, reducing cholesterol and triglycerides in blood. It also aids in reducing the stiffness experienced by persons with rheumatoid arthritis. Omega-3 fatty acid helps in the development of nerve tissue and vision.
Fish from salt water has more sodium and potassium than fish from fresh water. Calcium and phosphorus are needed for development and strengthening of bones and teeth and are higher in whole fish. Shrimp, crab and lobster have more calcium and iron and less phosphorus and copper than fish with fins. Copper and iron are needed for making haemoglobin (the red substance in blood) to prevent anaemia.
Natural source of iodine
Fish is the richest natural source of iodine, which is needed for the proper functioning of the thyroid gland and the prevention of goitre. Iodine is found mainly in the skin of fatty fish than in the flesh. A small amount of fluoride is found in fish to prevent brittle bones in children and the elderly. Sardines and mackerel have more vitamin D than yellowtail and flat fish. Vitamin B12 is high in fatty fish and shellfish. This vitamin is needed to prevent pernicious anaemia.
Large fish and fish high on the food chain such as sharks, king mackerel, swordfish and albacore tuna tend to have more mercury because they eat the smaller fish and the mercury builds up in their (larger) bodies.
Shellfish and caviar are high in cholesterol, which increases the risk of developing heart disease.
The Eskimos of the Arctic have less heart disease because of a diet rich in fish and omega-3 fatty acids, but those of us who live in the Temperate Zone and are experiencing a financial crunch may not be able to consume fish, especially fatty fish from the cold waters, every day. The dietary recommendation to get similar benefits is to eat at least six ounces of fish per week.
Marsha N. Woolery is a registered dietitian/nutritionist in private practice and adjunct lecturer at Northern Caribbean University; email: email@example.com.