Omega-3 fatty acids are “healthy” fats, which are thought to protect the body against heart disease. They help the heart beat more regularly, reducing blood “stickiness,” therefore making it less likely to clot, and protecting the arteries from damage. They also help to maintain healthy joints, and are associated with beneficial improvements in our mood.
Fish oil contains two omega-3 fatty acids: EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). These are found in certain fatty fish, but they can also be derived in the body from ALA (alpha-linolenic acid) from certain seeds and plant-based oils.
The body is however, inefficient at converting ALA into EPA and DHA, and therefore, if possible, it is best to consume fatty fish as your source of omega-3s, rather than plant-based sources alone.
A study, carried out in 2004, looked at the influence of ALA from flaxseed oil, comparing it to fish oil in terms of cardiovascular risk factors. They found that those who had fish oil added to their high omega-6 diet had a much higher level of EPA and DHA after a few weeks of supplementation, in comparison to those who had added flaxseed oil.
Researchers concluded that those taking fish oil had lower levels of small dense LDL (bad cholesterol), lower levels of triglycerides, and higher levels of HDL (good cholesterol), however this was not replicated in the ALA enriched diet.
Current recommendations for consumption
Currently the advice for most people is to eat no more than four portions of oily fish per week. The American Heart Association advise that:
- Patients without heart disease should eat a variety of fish at least twice a week. Also, include oils and foods rich in ALA (flaxseed, canola and soybean oils; flaxseed and walnuts).
- Patients with heart disease should consume about 1 gram of EPA+DHA per day, preferably from fatty fish. EPA+DHAin capsule formcould be considered only in consultation with a physician.
- Patients who need to lower triglycerides should consume 2 to 4 grams of EPA+DHA per day, provided as capsules under a physician’s care.
You should aim for at least 1 serving of oily fish, and 1 serving of white fish per week. A serving is roughly 100g (4 oz) of fresh, frozen or smoked fish, or 1 small tin of canned fish.
Fish high in omega-3 fatty acids
The highest sources have been listed first, for example, fresh salmon is higher in omega-3 fatty acids than tinned salmon:
- Mackerel (fresh or frozen) - EPA/DHA 1.25g/100g
- Kippers (fresh or frozen)
- Pilchards (canned in tomato sauce)
- Tuna (fresh or frozen)
- Trout (fresh or frozen)
- Mackerel (canned in tomato sauce or brine)
- Salmon (fresh or frozen) - EPA/DHA 1.80g/100g
- Sardines (canned in tomato sauce) - EPA/DHA 0.98g/100g
- Herring (fresh or frozen)
- Salmon (canned in brine)
- Tuna (canned in oil)
- Crab (canned in brine)
- Cod (fresh or frozen) - EPA/DHA 0.28g/100g
- Haddock (fresh or frozen)
- Tuna (canned in brine or water)
To preserve the omega-3 content, steaming is the best cooking method, however grilled, baked or canned oily fish are also valuable sources of these beneficial fatty acids.
Here are a few recipe ideas:
- Canned salmon in low fat salad cream, served with multi-seed bread and salad.
- Mackerel with chopped cucumber and limejuice dressing, served with spiced couscous.
- Canned sardines with mixed bean salad and tossed leaves.
- Stir-fried salmon with noodles and mixed vegetables.
Melanie Thomassian is a dietician, and author of Dietriffic.com, an online resource for credible dietary advice, exercise tips, and much more