Fish oil refers to very unique fats found within fish. Many types of fat are found within fish, but of significance when discussing fish oil supplementation are two very long chain Omega-3 fatty acids; eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Different fish species possess different amounts of these two key fats, yet as a general rule fish provide approximately 30% of their fat as either EPA or DHA. The most commonly available fish oil supplements provide oil which contains 18% EPA and 12% DHA.

It is scientifically accepted that EPA and DHA are the molecules found within fish oil which benefit health. Fish oil concentrates, providing greater than 30% EPA and DHA have become readily available. These concentrates are superior to non concentrates for a number of reasons:

• Each capsule of a concentrate will deliver much more EPA and DHA compared to capsules of non- concentrated oils.
• The process of concentration simultaneously cleans the oil. Concentrates are likely to possess much lower levels of contaminants (mercury, PCB’s, dioxins, etc) compared to non concentrates.
• A concentrate can be made to be much higher in EPA, or much higher in DHA. For most applications (cardiovascular, mood/ behavior, inflammation) oil with more EPA than DHA is preferred. In pregnancy oil with more DHA is usually preferred.

When seeking fish oil supplements attempt to select a product which contains at least 60% EPA and DHA combined. Oils with 70%, or even 80% EPA and DHA have become available and are an excellent option. We propose that oil with at least a 3:1 ratio of EPA: DHA be used. Higher EPA: DHA ratios are available. Oil with greater content of DHA than EPA is reserved for pregnant women. Please see table 1 for more detail regarding dosages used in various settings.