What Is Fish Oil Made Of?

Fish oil contains a type of important lipid that is used in the human body as a structural component in the membranes of cells. It is found mostly in nerve cells of the brain and parts of the immune system. The function of fish oil is intimately tied to its composition; no other type of nutrient can fulfill its obligations.

Significance

The fat found in fish oil is derived from the tissue of the animal. Fish do not synthesize the oil directly, but they accumulate it from consuming algae. Therefore, fish higher up on the food chain will have higher levels of oil in their tissue. Humans need fish oil in the diet, so it is passed directly to us in the food chain.

Fatty Acids

Fish oil a fatty acid, a molecule made out of a long chain of hydrogen and carbon atoms. Carbon can bond with up to four other atoms. In the structure of fatty acids, it bonds to two fellow carbons on either side and two additional hydrogen atoms. Only the final carbon at the end is bonded to three hydrogen atoms. Some fatty acids, however, contain double bonds between the carbon atoms. This is known as unsaturated fat. The double bond prevents the carbon from bonding to one of the two hydrogen atoms, so unsaturated fat is missing one or more of them.

Oil

Oil contains all of the characteristics of a lipid: it lubricates and repels water. Oil is generally a type of unsaturated fat. The double bonds prevent the unsaturated fat from packing tightly together, because it causes the structure of the fat to bend, so it is not very dense. This allows the oil to exist in a liquid state at room temperature.

Omega-3 Fatty Acids

Fish oil is made out of a type of unsaturated fatty acid called omega-3 fatty acids. More precisely, it is a polyunsaturated fat, meaning that there are multiple double bonds in its structure. Omega-3 is so named because the first missing hydrogen atom, and thus the first double bond, is found on the third carbon atom.

Types

According to the Purdue Research Foundation, there are generally two types of omega-3 fatty acids in fish oil. Eicosapentaenoic acid, or EPA, has five double bonds and a carbon chain of 20 atoms. Docosahexaenoic acid, or DHA, has six double bonds and a carbon chain of 22 atoms. A third type, alpha-linolenic acid, is found primarily in nuts and vegetable oils instead.