Fats and omega 3
The recommended daily intake of essential fatty acids, including omega 3 and omega 6, has been set by the Government at six per cent of our dietary energy total. It has also recommended a weekly omega 3 target of 1.5g.
Department of Health guidelines state that we should all eat at least two portions of fish every week, and one of those portions should be oily fish, such as salmon or mackerel.
Surveys show that most people currently only eat one third of a portion of oil-rich fish per week and are therefore falling short of the recommended intake and the associated health benefits of omega 3 fats.
Fatty acids are the building blocks of fat and there are three different types: saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids.
While monounsaturated and polyunsaturated fats can lower blood cholesterol and help reduce the risk of heart disease, saturated fats can raise blood cholesterol and increase the risk of heart disease.
There is a special sub group of polyunsaturated fatty acids known as Essential Fatty Acids (EFAs). They are called 'essential' as they are not easily manufactured by the body and must be provided by food. They are split into two groups:
Omega 3 These are found in oily fish, fish oils, some vegetable oils and some nuts and seeds.
Omega 6 These are found in vegetable oils, nuts, seeds and grains. In general we get sufficient omega 6 fats in our diet from vegetable oils used in cooking, polyunsaturated spreads, nuts, seeds and grains. Omega 3 fats, however, are found in fewer foods so it is important to ensure we get enough, especially by eating more oily fish.
Omega 3 fats are needed for the body's normal growth and development. They are used to maintain the membranes of all cells including those of the nervous system, the liver, eyes and kidneys. They are also vital for good muscle function and for blood clotting.
Omega 3 fats are part of the family of 'good' polyunsaturated fats and there is increasing evidence that omega 3 fatty acids, when eaten as part of a healthy diet, can help maintain heart health.
They have been shown to lower blood pressure, reduce the risk of heart disease and strokes, and protect against heartbeat abnormalities. They are thought to reduce the risk of heart disease through their effect on blood triglyceride (lipid) levels, rather than in the reduction of blood cholesterol.
Omega 3 fats are also vital to normal brain function. The need for omega 3 is increased significantly during the last three months of pregnancy as it is needed for the development of a baby's brain and eyes. It is particularly important for the mother-to-be to get the correct levels of omega 3 from dietary sources during this time.
Scientific evidence is emerging that long-chain omega 3 fats may also help to increase concentration span, and may aid those with attention deficit disorder, Alzheimer's disease or depression.
In addition, omega 3 may be beneficial to anyone suffering from psoriasis and inflammatory conditions, such as rheumatoid arthritis and some bowel disorders.
Omega 3 fats occur naturally in seeds as alpha linolenic acid (ALA). However, the most effective omega 3 fats occur naturally in oily fish as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Good sources of ALA include: linseed (flaxseed) oil, linseeds, soya bean oil, pumpkin seeds, walnut oil, rapeseed oil and soya beans.
The body can convert ALA into EPA and DHA, but not very efficiently. This is why oily fish plays such an important role in our diet. Oily fish contains EPA and DHA in a 'ready made' form that the body can use easily.
The main sources of oily fish in the UK include salmon, trout, mackerel, herring, sardines, pilchards and kippers, either fresh, frozen, canned or smoked. Tinned tuna does not count as it does not contain the high levels of oils found in fresh and frozen tuna.
|Food source omega 3||(g per 100g)|
|Cod liver oil||20.0|
|Linseed (flaxseed) oil||50.0|
|Soya bean oil||7.3|
|Hemp seed oil||2.0|
If you follow either a vegetarian or a vegan diet, your main dietary source of omega 3 will be from ALA (alpha linolenic acid). As the conversion of ALA in the body to EPA and DHA may not be sufficient to provide these two vital fatty acids in the amounts the body needs, lots of plant sources of ALA must be eaten. An additional source of omega 3 may be required in the form of a supplement to maintain healthy levels.
For those who choose not to eat fish, supplements are a sensible way to get the omega 3 that the body needs. Cod liver and fish oil capsules are a good source of EPA and DHA and in some cases contain vitamins A and D as well.
However, if you are taking a supplement that contains vitamins A and D it is important not to exceed the recommended dose. If you are taking any medication you must seek your doctor's advice.
We can provide you with information about healthy eating through our nutrition advice service, fact sheets, publications, the nutrition labelling on our packaging and our website, Waitrose.com Look out for signs on our fresh fish service counters, on shelf edge tickets and for packaging stating 'high in omega 3'. They indicate oil-rich fish, which typically contain omega 3 levels greater than 1.5g per 100g.
- Try serving kippers or kedgeree for breakfast
- Smoked mackerel, pilchards or sardines on toast make a tasty midday snack
- Use oily fish in main dishes instead of meat
- Add to salads or use as a filling for jacket potatoes
- Encourage children to eat oily fish by including it in sandwiches or by serving it in fishcakes
- Make pâté using salmon, mackerel or trout
- Make salmon and tuna kebabs for the barbecue
- Try smoked salmon with pasta and half-fat crème fraîche
For recipes that include oily fish, visit our recipe pages.
- Dietary Reference Values (DRVs) for Food Energy and Nutrients for the United Kingdom (1991). Report of the panel on DRVs to the Committee on Medical Aspects of Food Policy (COMA).
- National Diet and Nutrition Survey Adults aged 19 to 64, Volume 1 (2002).
Nutrition Advice Service
Berkshire RG12 8YA
Tel: 0800 188884
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