Fish And Human Nutrition
- Part 1 -

By:- Bijayalaxmi Nongmaithem / Ajit Kumar Ngangbam *

INTRODUCTION In common, we can say, "we are what we eat". What we eat is both important for our physical activity and mental health. Therefore it is important to have the best nutrition. From this context, fish is one of the main sources of protein and fat, but it also has other qualities that make it very valuable as a nutrient.

Fish have always been important to man. Man has always eaten fish. The fish consumption per capita is expanding globally, and the pattern of fish consumption is changing. In developing countries fish is still very much an essential food and a main source of protein.

Fish makes a vital contribution to the survival and health of a significant portion of the World's population. Fish is especially important in the developing world. Often referred to as "rich food for poor people," fish provides essential nourishment, especially quality proteins, fats, vitamins and minerals. For those involved in fisheries, aquaculture and fish trade, fish is a source of income.

India produces about 6.57 million metric tons fish every year. The inland-sector, which has a growth rate of 6 per cent, contributes around 55 per cent of it.

According to Dr. S. Ayyappan, Deputy Director General (Fisheries) of Indian Council of Agricultural Research, India is home to more than 10 per cent of global fish biodiversity with 2200 species of fish and shellfish in the marine and inland waters. Manipur state produces about 18,600 tonnes of fish annually.

The average fish yield from FFDA ponds in the state is about 2.4 tonnes /ha / year. Inadequate stocking of quality seed in lakes and rivers is the major cause for the huge gap between the potential and the present production level of 18,600 metric tonnes.

The total required quantity of fishes in the state is around 28,000 tonnes in a year. Manipur obtains more protein from the fishery products than red meat.

Extensive aquaculture has been in practice in the State for the past several years and fish provides a source of income which can be used to purchase other additional food items. Although the people are generally vegetarians, eating fish is allowed. No social function or ceremony is held without fish.

PROTEINS FROM FISH HAVE HIGH NUTRITIONAL VALUE

Proteins are important for growth and development of the body, maintenance and repairing of worn out tissues and for production of enzymes and hormones required for many body processes.

The importance of fish in providing easily digested protein of high biological value is well documented. On a fresh weight basis, fish contains a good quantity of protein, about 18-20%, and contains all the eight essential amino acids including the sulphur containing lysine, methionine and cysteine.

Fish, meat and dairy products are the main sources of proteins in the human diet. Fish is mainly eaten for its protein contents. Our body utilizes proteins from fish better than proteins from beef, pork, chicken and milk.

All the proteins from fish are adequate, important and digestible. The amount of connective tissue in fish muscle is quite low and softens and dissolves more readily when heated compared to the connective tissue of land animals. The connective tissue is easily broken down by digestive enzymes making it very easy for the body to digest.

FATS FROM FISH ARE MORE HEALTHY

The fat content of fish varies depending on the species as well as the season but, in general, fish have less fat than red meats. The fat content ranges from 0.2% to 25%.

However, fats from fatty fish species contain the polyunsaturated fatty acids (PUFAs) namely EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) (omega 3 fatty acids) which are essential for proper growth of children and are not associated with the occurrence of cardiovascular diseases such a coronary heart disease.

In pregnant women, the presence of PUFAs in their diets has been associated with proper brain development among unborn babies. In other studies, omega 3 fatty acids have also been associated with reduced risk of preterm delivery and low birth weight. The fat also contributes to energy supplies and assists in the proper absorption of fat soluble vitamins namely A, D, E, and K.

The fat in fish contains a larger portion of Omega 3 and other unsaturated fatty acids that are healthier than the saturated fat of read meat. A large intake of the saturated fat in red meat is one of the main causes of cardiovascular diseases, while the unsaturated fat of fish and vegetables does not have this effect.

In addition, the types and proportions of dietary fats found in fish are generally more "heart healthy" than the fats found in other protein foods. This is due to its relatively high share of unsaturated fat. This is probably why fish, which is cold blooded, has higher contents of unsaturated fat.

Fish that live in cold areas have the highest content of polyunsaturated fatty acids. Excessive dietary intake of saturated fats can significantly raise the blood cholesterol level in humans. This increases the risk of cardiovascular diseases.

Approximately 50% of the fatty acids in lean fish and 25% in fattier fish are polyunsaturated fatty acids. In contrast, the polyunsaturated and saturated fatty acids in beef are 4-10% and 40-45%, respectively, of the total fatty acids present.

To be continued.....