The Fish Foundation

The Dietary Sources of Omega-3 Polyunsaturates

The body can’t easily manufacture omega-3’s like EPA and DHA - they are best supplied by our food. Luckily, the one organism that can make them - plankton - is eaten by certain types of fish (which are in turn, eaten by other fish). We can eat these fish and so get the omega-3 the plankton made originally. Alternatively supplements can be used, which contain the EPA and DHA found in these oil-rich fish. Fish are generally to be preferred over supplements, since they supply other important nutrients like vitamins and minerals also. However, some people are not able or willing to eat fish, and for them supplements, or fish oil supplemented foods, are a feasible and sensible way to get omega-3.

A table showing the amounts of the various long chain omega-3 polyunsaturates provided by various seafoods is available on the fish oils page.

If you are a vegetarian, you can get one of the Omega-3 fatty acids (alpha-linolenic acid or ALA) from sources such as linseed oil or rapeseed oil, though to be most useful to body, the ALA must first be converted to EPA and/or DHA. Modern diets make this conversion process inefficient, (see the omega-3 page) so that lots of ALA must be eaten to produce levels of EPA and DHA comparable to those that can be obtained by eating fish. 

How much Omega-3 do you need ?

Various studies have shown that fairly small amounts of Omega-3’s can make a big difference to heart risks. Current thinking is that around 400 mg a day is enough to reduce risk quite substantially. You can get it by eating oil-rich fish or by simply taking one or more concentrated fish oil capsules a day.

Through diet

Eating oil-rich fish once or twice a week will make a good contribution towards supplying the amount of Omega-3 you need to improve general health

The table  on the fish oils page  shows the omega-3 supplied by a number of items (the seafoods can be fresh, frozen, canned or smoked).

Through supplements

For some people supplements are the best way to take Omega-3. Cod liver oil is a good source of EPA and DHA. If you are taking another type of supplement, make sure you read the label to check that EPA and DHA are listed. With products like cod liver oil, containing vitamins A and D, it is recommended that you do not exceed the suppliers dosage instructions. With fish body oil capsules (which contain far lower amounts of vitamins A or D) this restriction is not important.

The following table shows a range of supplements which provide omega-3.
Some conditions, or the drugs taken to help them, are not compatible with high doses of Omega-3 fish oil. For example, as Omega-3 thins the blood, anyone taking Warfarin or any another anti-coagulant drug, should not increase their levels of Omega-3 without seeking advice from their doctor. Similarly, other prescription drugs may interact with the omega-3 polyunsaturates, and if you are taking such drugs, you should check with you doctor before taking omega-3 supplements on a daily basis. 

* because of the possibility of excessive intake of vitamins A or D, the manufacturers recommendations on dosage must not be exceeded

While eating more fish, or taking more Omega-3, can help reduce your risk of ill-health, other elements of diet and lifestyle are also valuable: