Not surprisingly, fish oil is made by extracting the oil from certain varieties of fish, so it can be purified for direct supplementation. The best fish oil supplements often use these fish sources: salmon, anchovy, sardine, and mackerel. 

There is an incredibly long list of health benefits attributed to fish oil. Most of the research showing the positive effects of omega-3 fatty acids in the diet comes from studies of either high-fish diets or fish oil supplementation. Fish oil has particularly been hailed for its mood-balancing ability and effects in the treatment of mental health conditions, likely due to its high EPA content.

Key Health Benefits of Fish Oil

Fish oil is considered the best source of omega-3 fatty acids, such as EPA and DHA. Omega 3 fatty acids have shown benefits to the cardiovascular and immune systems and the brain and mental wellbeing. 

There has been very little research to see if other sources of omega-3 supplementation provide the same health benefits. In particular, it is only fish oil that is responsible for the mental health benefits of omega 3. Doses as low as 1g of combined EPA and DHA have been shown to help reduce and even eliminate conditions such as depression, schizophrenia, ADD, and bipolar disorder. It is the content of EPA that is especially associated with mood-balancing effects, while DHA is associated with proper mental function.

Fish Oil Source Varieties 

Fatty fish that are higher on the food chain (eg. Tuna) are generally not used as sources of supplemental fish oil due to the potentially higher concentration of toxins and heavy metals stored in their fat. Deep, cold water fish are the preferred source as they have the lowest levels of contaminants. Very often, supplement companies will give a list of possible fish sources for their oil with a note that oil contents will change with the seasons and with different availabilities of certain fish. Some companies will not list their fish sources at all for this reason. It is often a good idea to take a supplement with a known source so you can be confident of its nutritive and contaminant content.

Key Considerations When Selecting Fish Oil Supplements

The freshness of the fish used to make fish oil is extremely important. Fish that are not fresh create a "fishy" taste and can cause the production of oil that is more difficult to digest, causing the common complaints of "burping up fish" after supplementation. When fish oil is made from fresh fish and extracted properly, the fish taste should be very light and barely perceptible. Fresh fish oil is also less oxidized, and thus can provide more health benefits and will stay fresh longer. Taking a liquid fish oil instead of capsules can ensure that you know, and can taste the freshness of your supplement.

Fish Oil Extraction Methods

Fish oil can be extracted from the fish using a cold press, centrifuge or solvent extraction. Cold press extraction is the best method because the temperature is carefully controlled and the oil removed is less likely to be oxidized. Centrifugation uses the force of spinning the fish in a centrifuge to remove the fat. Centrifuges tend to heat up with the length of use required to extract the oil and this can cause oxidation, which damages the fish oil. Solvents can also be used to extract fish oil, but remnants may remain after processing and be present in your supplement. In general, cold pressing is considered the best possible means of extraction to keep the oil fresh and pure.

Understanding Dosing & Omega Content 

Dosage recommendations for omega-3 fatty acids vary depending on the disease process or overall goal. If your goal is to lower your triglyceride level, for instance, it is recommended you consume 3-4 g/day, whereas studies aimed at treating depression found that only 1 g of EPA/day showed better results than higher dosages of 2 and 3 grams. It is important to know that whatever dose you are recommended, you need to be sure your supplement contains the right stuff. On the bottle, you will see the total omega content, as well as the specific contents of DHA, EPA, etc. If you have been advised to take 2 g of EPA + DHA/day, make sure you are looking at the breakdown and that you are following these numbers, rather than looking at the "total omega" content.

Shopping Tips For Finding The Best Fish Oil Supplement

Fish oil supplements have become widely available, so it is very important to ensure that you are getting the best possible one. Use a trusted brand that lists the fish sources used, and clearly states the content of EPA and DHA. Most liquid capsules of fish oil cannot contain a large enough dose, such that to get the doses listed above, you may have to take anywhere from 6 – 20 caps a day. Taking a liquid can easily bypass this problem. Liquid fish oils come in a variety of flavours, making them quite simple to supplement. Doses are generally between 1tsp and 1Tbsp daily to achieve the desired EPA+DHA content.