Why take fish oil?
Fish oil is a common dietary supplement derived from fatty fish such as mackerel, salmon and anchovies. Fish oil contains high amounts of the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). EPA and DHA have numerous roles in the body and are primarily responsible for the health benefits of fish oil consumption.
About omega-3 fatty acids
Omega-3 fatty acids are a type of polyunsaturated fatty acid that cannot be made in the body and therefore must be obtained from the diet.
The three major types of dietary omega-3s are:
- Alpha-linolenic acid (ALA)
- Eicosapentaenoic acid (EPA)
- Docosahexaenoic acid (DHA)
ALA, a short-chain fatty acid, is found in plant-based foods such as chia and flax and is not present in fish oil. EPA and DHA, on the other hand, are long-chain fatty acids found in animal sources including fatty fish, fish oil supplements, krill oil supplements and certain fortified foods.
Extensive clinical and epidemiological research has revealed numerous health benefits of EPA and DHA. DHA is found in the brain, retina and heart and is a particularly important dietary nutrient for infants and children as they grow and develop. EPA is heavily involved in the inflammatory pathway and may help prevent or alleviate diseases resulting from chronic inflammation. These include heart disease, stroke, obesity and arthritis.
How much do I need?
The following recommended adequate intakes (AI) for omega-3 fatty acids were developed in 2002 by the Food and Nutrition Board in the United States. These recommendations were based on the previously determined Recommended Nutrient Intakes (RNI) in 1990 by Health and Welfare Canada.
Table 1: Recommended Adequate Intakes (AI) for Omega-3 Fatty Acids (Food and Nutrition Board, USA, 2002).
||19 years and older
Why increase my omega-3 intake?
In general, the typical North American diet provides far too much omega-6s (another type of fatty acid required for good health) and not nearly enough omega-3s. While both omega-3 and omega-6 fatty acids are necessary for normal body structure and functioning, consuming the correct ratio between the two is very important because they work together in the body.
Humans should ideally consume no more than 4 times more omega-6s than omega-3s (i.e., a ratio ranging from 1:1-4:1 of omega-6s to omega-3s). A ratio that is skewed toward excess omega-6s-as is typical in the Western dietary pattern has been linked to the development of many diseases.
Therefore, the best way to achieve a healthy ratio between omega-6 and omega-3 fatty acids is to increase your intake of omega-3s.
Dietary sources of omega-3s
Fatty fish are considered to be the most widely available dietary source of EPA and DHA. In fact, several studies have indicated an inverse relationship between the consumption of fish containing EPA and DHA and the risk of cardiac death. Canada's Food Guide recommends at least two 75-g servings of fish per week.
Top seafood sources of omega-3s include:
However, it is important to note that excess consumption of certain types of fish (typically large predatory fish that eat other fish) could result in exposure to toxic levels of mercury. Health Canada recommends limiting the consumption of fresh/frozen tuna, shark, swordfish, marlin, orange roughy and escolar to the following:
||Children 5-11 years of age
||Children 1-4 years of age
|150 g per week
||150 g per month
||125 g per month
||75 g per month
The health benefits of fatty fish intake can also be obtained by taking fish oil supplements. Fish oil is derived from the tissues of fish such as anchovies, herring, sardines, mackerel, salmon and smelt, among others. Fish oil is available commercially in capsule and liquid form.
Other types of fatty acids found in fish oil
Some types of fish oil supplements deliver omega-7 fatty acids, specifically palmitoleic acid, which may have positive health benefits including reduced inflammation, LDL ("bad") cholesterol levels and insulin resistance.