Why You Should Include Fish & ShellFish In Your Diet
Fish provides another class of high-protein or tissue-building food. As this term is generally understood, it includes both vertebrate fish that is, fish having a backbone such as salmon, cod, shad etc. and many other water animals such as lobsters, crabs, shrimp, oysters and clams. Fish can usually be purchased at a lower price than many other food items and for this reason possesses an economic advantage over them. Some varieties of fish are sought more than others, the popularity of certain kinds depending on the individual taste or the preference of the people in a particular locality.
As is well known, fish is an extremely perishable food. Therefore, when it is caught in quantities too great to be used at one time, it is preserved in various ways. The preservation methods that have proved to be the most satisfactory are canning, salting and drying, smoking and preserving in various kinds of brine and pickle. As such methods are usually carried out in the locality where the fish is caught, many varieties of fish can be conveniently stored for long periods of time and so distributed as to meet the requirements of the consumer. This plan enables persons far removed from the Source of supply to procure fish frequently.
COMPOSITION OF FISH:
In general, the composition of fish is similar to that of meat, for both of them are high-protein foods. However, some varieties of fish contain large quantities of fat and others contain very little of this substance, so the food value of the different kinds varies greatly. As in the case of meat, fish is lacking in carbohydrate. Because of the close similarity between these two foods, fish is a very desirable substitute for meat. In fish, as well as in shell fish, a very large proportion of the food substances present is protein. This proportion varies with the quantity of water, bone, and refuse that the particular food contains, and with the physical structure of the food. The percentage of fat in fish varies from less than 1 per cent in some cases to a trifle more than 14 per cent in others. This variation affects the total food value proportionately.
The varieties of fish that contain the most fat deteriorate most rapidly and withstand transportation the least. Fish containing a large amount of fat such as salmon, turbot, eel, herring, halibut, mackerel, mullet, butterfish and lake trout have a more moist quality than those which are without fat such as cod. Like meat, fish does not contain carbohydrate in any appreciable quantity. In fish, mineral matter is quite as prevalent as in meat.
CLASSES OF FISH:
According to the quantity of fat it contains, fish may be divided into two classes, Dry, or lean fish, and Oily fish. Cod, haddock, smelt, flounder, perch, bass, brook trout, and pike are dry, or lean fish. Salmon, shad, mackerel, herring, eel, halibut, lake trout, and white fish are oily fish. This latter group contains from 5 to 10 per cent of fat. Fish may also be divided into two classes, according to the water in which they live, fish from the sea being termed ‘salt-water fish’, and those from rivers and lakes are ‘fresh-water fish’.
FOOD VALUE OF FISH:
The total food value of fish, as has been shown, is high or low, varying with the food substances it contains. Therefore, since weight for weight, the food value of fat is much higher than that of protein, it follows that the fish containing the most fat has the highest food value. Fat and protein, as is well known, do not serve the same function in the body, but each
has its purpose and is valuable and necessary in the diet. So far as the quantity of protein is concerned, fish are valuable in their tissue-forming and tissue-building qualities. Nutritive value of fish may be lost in its preparation, if proper methods are not applied.
To obtain as much food value from fish as possible, the various points that are involved in its cookery must be thoroughly understood. When the value of fish as a food is to be determined, its digestibility must receive definite consideration. Much depends on the way it is cooked. The ease with which fish is digested is influenced largely by the quantity of fat it contains. In addition to the correct cooking of fish and the presence of fat, a factor that largely influences the digestibility of this food is the length of the fibres of the flesh. It will be remembered that the parts of an animal having long fibres are tougher and less easily digested than those having short fibres.