Omega 3s are polyunsaturated fats characterized by a double bond in the 3 position. Along with omega 6s, omega 3s are often referred to as essential fatty acids since they are critical to certain body functions yet not readily created in the human body and must be derived from dietary sources.
The parent omega 3 fatty acid is alpha linoleic acid (ALA, sometimes given the acronym LNA). ALA breaks down to eicosapentaenoic acid (EPA) and
docosahexaenoic acid (DHA). EPA and DHA with their strong anti-inflammatory effects and role in body functions are probably the most beneficial forms of omega 3s in the body. Unfortunately in some circumstances ALA does not readily break down to EPA and DHA. Exacerbating the situation is that ALA is usually not that common in most Western diets.
The most common sources of omega 3s are marine products such as fish like salmon, mackerel, sardines, and anchovies. Marine sources are more likely to contain the downstream forms EPA and DHA. Flaxseed, walnuts, and rapeseed also contain omega 3 but principally in the form of ALA.
It is now pretty clearly established that omega 3s can be effective in lowering triglycerides, but some doubts remain over their therapeutic use in combating other health conditions and diseases. With more readily available EPA and DHA, fish oil is thought to be more
protective against cardiovascular disease than flaxseed oil. However, recent findings seem to indicate that fish oil but not flaxseed oil may also increase the risk of prostate cancer.
