Replies

Most people get theirs in the form of gellpills containing fish oil. I've talked to one enthusiastic user who switched to flaxseed oil because the fish oil made him pungent.

The omega-3 fatty acid could be separated from the rest of the fish oil which could contain stinky nitrogenous proteins, but it would be prohibitively expensive. It would also not entirely solve the problem since some of the fishiness comes from rancidity. The more highly unsaturated an oil, the more prone it is to becoming rancid through oxidation. The addition of vitamin E, both to the fish oil and to the diet, helps to reduce this oxidation. Here's a link to an interesting description of the process of oil extraction from various foodstuffs:

Oils: Peanut, Olive, Marine, and Bitter Almond

Marine Oils

In order to extract the oil, raw fish is placed into a continuous cooker and heated to a temperature of 95 C. This temperature is reached by heating the meat directly, or indirectly, with steam. Heating helps to coagulate proteins in the meat (Bimbo, 1990). As the proteins coagulate, the heating also helps recover the fat and water from the fish meat (Pigott, 1967).

The cooked meat is collected and conveyed to screw presses (Bimbo, 1990). The presses help to remove any remaining oil and water from the fish. This resulting liquid is called pressliquor. The pressliquor is sent to undergo a combination of decanters and separators.

Decanters are used to separate solid fish meat from the liquid. The pressliquor is pumped into cylindrical bowls and conveyers that rotate. The rotation of the decanter helps to force the solids to the outside of the bowl where they are collected. The remaining liquid continues through the process.

After decanting, the pressliquor is pumped through a separator. The high speed rotation of the separator plates result in the separation of the oil from the water.

You may want to tell the following to the user of flaxseed oil:

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the two principal fatty acids found in fish and are known as omega-3 fatty acids. DHA can also be obtained from other marine sources, such as algae (algal oil). EPA and DHA are polyunsaturated fats ("good" fats, as opposed to saturated fats which increase the risk of heart disease.) The body has a limited ability to manufacture both EPA and DHA by converting the essential fatty acid, alpha-linolenic acid (ALA) — found in flaxseed oil, canola oil or walnuts. But this ability is lessened if the diet is too high in omega-6 fatty acids from vegetable oils from corn, sunflower, soybean or safflower.

The bottleneck is this limited ability. Simply increasing the precursor won't increase the product.