Is fish a health hazard?

People consuming PUFA are less likely to suffer from cardiovascular disease. As humans are not able to synthesize omega 3 polyunsaturated fatty acid (PUFA), they must be supplied to the body in the diet. These fatty acids accomplish the synthesis of other essential fats.

One important fatty acid is Dechexanoic Acid (DHA), present in high concentration in retina, cerebral cortex, testis and sperm. It is particularly needed for the development of the brain and the retina.

The outer segment of retinal rods contains very high concentration of DHA which plays an important role in high fluidity necessary for functioning of Rhodopsin (a protein in external segments of the rods of the retina).

Thus, it plays an important role in functioning of the eye. Similarly they are essential to keep your heart healthy as they tend to raise your HDL level and decrease your LDL level. HDL is called good cholesterol and LDL bad cholesterol. It is found that people having less HDL cholesterol are more prone to heart disease or they may have contradicted their first heart attack.

All these fatty acids are present in fish; thus, fish is a good source of essential fat in a diet. Also these PUFA inhibit aggregate of platelets thus, inhibiting formation of blood clot.

However, on another study the opposite was found; increased fish consumption = increased cardiovascular diseases. This result was based on a specific study on fresh water fish from the Finnish Lake where mercury content was high.

Fish is the primary source of mercury exposure in humans. Mercury is a toxic metal that can exist as pure element or in a variety of organic and inorganic forms. Mercury is harmful in all its forms. It can cause immunosensory, neurological motor and behavioral dysfunction.

Mercury increases the production of super-oxide anion which can damage heart cells by causing lipid per-oxidation. Super-oxide anion can even break DNA strand and can lead to a complete damage of heart cells.

Though it is a medical fact that fish are good for a healthy heart, fish source and the amount consumed is very important otherwise this preventive treatment may act as a poison.

Methyl mercury is another form of poisoning mercury. It is almost completely absorbed from the digestive tract and easily accumulated in the brain and damaging its tissues. It is also seen that methyl mercury poisoning cause damages to specific areas of the brain, such as visual cortex or granule layer of cerebrum.

Methyl mercury poisoning symptoms include visual and hearing abnormalities, muscle weakness, tumor and mental deterioration. The fetal brain is much more sensitive for low doses of methyl mercury than adult. Therefore, pregnant women should be more cautious about their fish intake, they must be careful for the source of fish.

The guidelines about good fish source can be collected from the local environmental and health authorities.

Once higher level of mercury is detected in the water, the state post fish advisories must warn consumers to limit their intake.

However, according to Science Journal [278: 1904 - 1905 (1997)], 7 ounces of fish per week is considered to be good and healthy for a woman of 60kg.

Overall fish is an important part of a balanced diet; it is full of vitamins, and other nutrients, including essential fatty acids. It helps in lowering cholesterol level and in controlling blood pressure.

It is therefore important that you do not cut fish from your menu but be little cautious about the source and the amount of intake.