Fish is one of the most popular food items of the non-vegetarians. It is nutritionally rich and tasty. Fishes varies in shape, size, colour, skin, bone, and taste. It is unique animal meat that is rich in essential fatty acids. They contain protein and many other major nutrients. Fish is a staple food in many parts of India and Japan.
The taste of fish depends upon its origin, whether from salt or fresh water, its fat content, and whether it is eaten fresh or preserved. I doubt there are any other food items those are cooked such a varied ways and eaten. Fresh fish is taken as steamed, baked, boiled, as various curies, roast, fries, grills, pickles, cutlets, finger chips, biriyani etc. Among this curries and fries are the most popular Indian preparations. Dry fish is taken as fries, chutney, and also in powder form.
Fish is a good source of proteins and it constitutes about 17 - 20 %. Fish proteins are good sources of all essential amino acids. Fish protein beings rich in lysine and threonine supplement effectively with cereal proteins. Small fish eaten along with bones are a rich source of calcium. The caloric value of the edible portion depends upon its fat content and thus on the season. During the spawning season the fat content may rise and the caloric value increases. Studies have proved that eating fish decrease heart disease.
Scientists have also discovered that omega 3 fatty acids are essential for the healthy development of the eyes and brain. Fish has been described as a food for the brain but there is no reason to believe that a fish eating population is in any way mentally superior to those who do not eat fish or those who are vegetarians.
Fish is a rich source of long chain n-3 PUFA which are biologically more active than their parent member namely alpha linolenic acid in producing several health benefits. Those who have a taste for fish are advised to take about 100 - 200 gm of fish twice a week. Fish oil capsules that containing large quantity of long chain n-3 PUFA are used in the treatment of hypertriglyceridaemia, thrombosis, and inflammatory diseases. Oily fish such as mackerel and trout have been shown to relieve some symptoms of psoriasis and should form a regular part of those patients diet. This may be due to the omega 3 fatty acids or to the large amounts of vitamin D present in it.
Salt-water fish is rich in iodine, phosphorous and calcium. Those who eat regularly salt-water fish generally will not have these mineral deficiencies. Fish also contain mineral copper. Vitamin A and D is also present. The oil from shark, cod, and halibut liver is very rich in these vitamins.
Why fish oils are good
Fish oils are available in capsule and liquid form. The cod liver oils are derived from cod and also from Pollock, satire, and whiting. Fish oils are from fish liver and fish body. The oil extracted from the fish livers is deodorised and then vitamin E and antioxidants are added to prevent it from going rancid.
The oil is an excellent source of vitamin A and D. Two teaspoons of cod liver oil provide about 1200ug of vitamin A, 20ug of vitamin D and about 2gms of omega 3 fatty acids. Because of high concentrations of these vitamins, cod liver oil has been used to prevent and treat conditions such as xerophtalmia; an eye disease caused by vitamin A deficiency and rickets a bone disease caused by lack of vitamin D.
Shark liver oils also contain squalene, which is utilised by the body to produce cholesterol. Glyceryl, a substance present in shark liver oil ethers may help to protect against cervical cancer. Fish body oils contain less vitamin A and vitamin D but are rich in omega fatty acids.
The consumption of fish and especially shellfish is one of the commonest causes of food allergy. Fish should be cooked properly other wise it can cause stomach upsets and skin rash. The danger of bones becoming caught in the throat is another disadvantage while eating fish. All bones should be removed from fish before serving to children. Steaming, baking or grilling fish is the best for health. Studies shows that smoking and pickling fish can produce compounds, which may be carcinogenic if eaten in excess.
Nutritive value for 100gms of the edible portion of common fishes*