Nutritional Values of Fish

Characteristics of a Fresh Fish

Smell

• A fresh fish should have little or no smell. The digestive tract of living fish contains enzymes. When a fish dies, these enzymes help bacteria penetrate the stomach wall. This causes fish flesh to start spoiling. An ammonia-like smell or an overpowering fishy odor indicates the fish is no longer fresh. It is old or has spoiled from improper refrigeration.

  
  

  

  
  

  Scales and Skin

• The scales of a fresh fish are tight on the skin, not loose or falling off or dried out. They are also bright, reflecting light easily, and have a metallic look. A very thin and clear mucus should cover the skin. Unscrupulous fish markets sometimes import fish dipped in a preservative chemical called formalin to appear fresher. If you're unsure, ask if the fish is really fresh or has been rinsed in a preservative.

  

  
  

  Flesh and Tail

• • A fresh fish has firm flesh that is not mushy or easily indented with your finger. It should not be separating from the bones. The tail should be very stiff with firm flesh as well. When buying a cleaned fish fillet, test the resiliency of the fillet's meat with your finger. Press down on the fillet. If the meat bounces back with its original shape, it is fresh. If the finger imprint remains, the fillet is about to spoil.

    

    
    

Fish Eyes

• • The eyes of a fresh fish should be bulging, clear and shiny, not cloudy or sunken into the head. If the eyes are cloudy, faded, milky or dull, the fish has aged a few days and is approaching a non-usable condition. The exception to this is for naturally cloudy-eyed fish types, such as the fresh water walleye pike and large catfish. Some ocean species of fish also have eyes that cloud shortly after death, such as snapper, grouper and flounder.

    

    
    

Gills and Fins

• • The gills must be red to pink, not gray or brown There should be no slime covering them. The fins should be intact, moist and and resistant to being pulled.

  

  
  

• Nutritional Values of Fish:

  
  

  Protein

• • Fish is a very good source of protein. Our bodies are not equipped to store protein, therefore consuming fish daily helps you fulfill your daily requirement.

    

Low Fat

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  1. • Fish is a great staple of a low-fat diet. The majority of fish contain low levels of saturated fats.

       

       
       

B Vitamins

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  1. • Fish contains B vitamins, which help to reduce stress, anxiety and depression. The B vitamins help your memory and reduce the risk of heart disease.

       

       
       

Vitamin A

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  1. • Vitamin A, which is found in fish, helps the body tissue mend and provides the mechanics for cell growth. Some other common ailments Vitamin A helps ward off are arthritis, acne and bronchitis.

       

       
       

       Calcium

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  1. • Fish also contains calcium, which helps to maintain strong bones and teeth.

  
  

  

  
  

  
  

What Vitamins Are in Fish?

Vitamins

• Vitamins found in fish include riboflavin, B2 and vitamins A, C and D. Riboflavin helps the body metabolize amino acids, fatty acids and carbohydrates. Vitamin A is important for vision and helps eyes adjust between light and dark situations, such as going from a darker indoor setting to a brighter outdoor setting. Vitamin A also helps keep eye cells, skin cells and mucous membranes healthy. Vitamin C aids in the production of collagen, helps in the absorption of vitamins A and E and promotes a healthy immune system. Vitamin D aids in the absorption of calcium, helps in the prevention of osteoporosis and promotes joint and bone health. Fish that are high in vitamin A include salmon--a single serving has 18 percent of recommended daily allowance, or RDA--and tuna--a single serving has 43 percent of RDA.

Omega-3 Fatty Acids

• In addition to vitamins, fish are an excellent source of omega-3 fatty acids. These nutrients offer a variety of health benefits. Heart-health benefits include a decrease in the incidence of heart disease, a reduction of blood pressure and help in the prevention of abnormal heart rhythms. Omega-3 fatty acids are also credited with helping to prevent arthritis and promoting healthy brain function. 

  
  

  

  
  

  Fish that are especially rich in omega-3 fatty acids include salmon, tuna, trout, sardines, perch, cod and sea bass.

  
  

  

Calcium and Phosphorus

• Calcium aids in bone health and helps prevent osteoporosis. Phosphorus aids in cellular processes, helps in digestion and assists in the formation of bones and teeth. A single serving of rainbow trout has 11 percent of the RDA for calcium, and a single serving of perch has 7 percent of the RDA for calcium. Both halibut and salmon are good sources of phosphorus.

Iron and Zinc

• Iron is a component of hemoglobin and helps transport oxygen in blood. Zinc aids in cellular processes, promotes a healthy immune system and supports growth and development. A single serving of salmon contains about 9 percent of the RDA for iron; a single serving of trout has 7 percent of the RDA for iron; and a single serving of cod has 5 percent of the RDA for iron. A single serving of flounder or sole contains 3 percent of the RDA for zinc.

Potassium and Magnesium

• Potassium aids in muscle function and cardiovascular health and promotes general health. Magnesium aids in the absorption of calcium, aids in muscle function and promotes heart health. Halibut is an excellent source of magnesium, and a single serving contains 20 percent of the RDA for this mineral. Salmon, flounder, sardines, and cod are all good sources of potassium.

How Much Protein Does Fish Have?

Types

• Different types of fish have different protein contents. For 3 oz. of cooked fish, the recommended serving size for an adult, average protein contents are as follows:

  Cod: 19.51 g
  Sole: 20.54 g
  Haddock: 20.6 g
  Halibut: 22.69 g
  Sockeye Salmon: 23.21 g
  Yellowfin Tuna: 25.47 g
  Canned Tuna (light, canned in water): 21.68 g
  Swordfish: 21.58 g
  Rainbow Trout: 20.63 g

Comparisons

• To give you an idea of how fish compares to other well-known sources of protein, below are the average protein contents of meats, beans and tofu. The serving size is also 3 oz., so the numbers can be compared equally with the list above.

  Chicken (fried, dark meat only): 24.35 g
  Chicken (fried, light meat only): 27.27 g
  Beef (rump steak): 18.48 g
  Beef (top sirloin, lean only): 25.81 g
  Pork loin or tenderloin: 21.75 g
  Black Beans (cooked): 6 g
  Baked Beans (organic, in tomato sauce): 4.2 g
  Tofu: 7 g

  

  As you can see, meat and fish have very similar protein contents, and fish has more protein than traditional vegetarian sources. As an added bonus, fish is low in calories, very low in fat, and high in Omega-3 fatty acids, making it a healthy way to add protein to your diet.
• Portions

• When you cook fish, you want to keep portion sizes in mind so you know how much protein you're really eating. Because fish loses water when cooked, to end up with 3 oz. of cooked fish you should start with a raw 4-oz. steak, or 5 to 6 oz. if you're working with whole fish.

Daily Requirements

• The recommended daily protein intake for an adult is .8 g for every kg (2.2 lbs.) of body weight, per day. This means that if you weigh 160 pounds, you need about 58 g of protein each day. Depending on your weight and the type of fish you choose, one portion of fish could satisfy almost half your daily requirement for protein.

Warning

• You should also be aware of mercury levels in fish that you consume regularly; the FDA maintains a list of mercury content in different types of fish, and issues special mercury advisories for women who are pregnant or nursing and children under the age of 6. 

  

  
  

  The American Heart Association recommends eating fish at least twice per week despite potential risks, but encourages adults to eat a variety of fish to minimize your risk of mercury consumption. If you are pregnant or nursing, or under the age of 6, you should avoid fish with the highest levels of mercury, like shark, swordfish, king mackerel and tilefish. Salmon, pollock, catfish and canned light tuna are generally lower in mercury and can be eaten more often.