Nutrition

Omega-3 Polyunsaturates

What is Omega-3? Which products have it in them?

The omega-3 polyunsaturates are a family of polyunsaturated fatty acids. Fatty acids are the building blocks from which edible oils and fats are made up. The polyunsaturates are characterised by the presence of certain structural features which mark them out as being different from other fatty acids. The polyunsaturates are essential nutrients for humans and indeed most if not all animals.

There are two important families of polyunsaturates, the omega-3 family, and the omega-6 family. Both are needed in the human diet for optimal health.

The omega-6 family is found mainly in vegetable oils such as sunflowerseed, sesame, corn, soy etc.

The omega-3 family is found mainly in fish, and especially in the oil rich fish such as herring, mackerel, sardines etc. Small amounts of the omega-3's are found in eggs.

Certain vegetable oils such as linseed (flaxseed), rapeseed (canola) and walnut oil contain a type of omega-3, known as the short chain type (alpha-linolenic acid). To be useful to the human body, these short chain omega-3s must first be converted to their long chain form. While the human body can in theory do this conversion, in practice, modern diets and lifestyles reduce the effectiveness of the conversion systems.

Roughly 10 times more of the short chain omega-3s must be consumed to have the same effect as the long chain form from fish oil.

Could you explain why I should take cod liver oil or fish oil supplements? I need convincing as Ieat a healthy diet and feel fit. 

If you eat plenty of oily fish (e.g. mackerel, herring, sardine, pilchard, salmon) then you don't need to take a supplement.

The reason most people (90% of the population according to the Institute for Optimum Nutrition) are deficient in omega-3s is that the typical Western diet has changed so much since the turn of the century.

Our reliance on processed foods, meat and dairy produce means that most of us eat less fish (particularly the oily fish which made regular appearances in the traditional British diet) and fewer of the nuts and seeds that provide vegetable-source omega-3 (which although not as good as fish oils are certainly better than no omega-3s at all).

The Department of Health, through its Committee on the Medical Aspects of Food Policy (COMA) recommendations, advises increasing oily fish consumption as does the British Nutrition Foundation.

You may not notice the deficiency now (skin condition is a good indicator - are you sure your skin is as velvety, plump and blemish-free as it could be?), but as you age your body will feel the lack and you will be less able to fend off diseases associated with growing older.

Fish and fish oils supply omega-3 nutrients.

What is the relationship between Omega-3 and cancer?

Cancer is less common in communities that eat large amounts of fish, and the reason is thought to be the presence in fish of the long chain omega-3 polyunsaturates.

Japanese women, for example, eat a lot of fish, and have a very low rate of breast, (and other) cancer. Men who eat fish frequently have a lower risk of prostate cancer. Stomach and intestinal cancers also appear to be less common in fish eaters.

It is difficult to be specific about this though, because in such studies, there are often several factors that are different, and which could explain the lower cancer incidence.

Laboratory studies have provided more support to the idea that the omega-3 polyunsaturates can reduce cancer risk. For example, tests have shown that cancer-treating drugs work more effectively when there is a good level of omega-3 polyunsaturates in the diet.

Other studies have shown that adding omega-3s to the diet helps to reduce the level of certain hormone-like substances, which tend to be present in higher amounts in cancer sufferers.

In summary, it can be said that while there are good grounds for believing that adding omega-3 polyunsaturates to the diet will help to reduce cancer risk, it is not yet proven beyond doubt.

I have heard of the benefits of Omega-3 for the developing foetus. Any info on safety or recommendation of salmon oil capsules. 1000mg oil, EPA 100-110mg, DHA 90-100mg?

The long chain omega-3 polyunsaturates are essential for the optimal development of the foetus. They are especially important for the formation of a healthy brain, eyes and nervous system.

Each is made up in large part from the long chain omega-3s and studies have shown that if the mother's diet does not provide sufficient omega-3, then the formation and function of the foetal organs can be impaired somewhat.

Salmon, like other oil-rich fish, is an excellent source of the long chain omega-3 polyunsaturates. Approximately 20% of salmon oil is made up of the omega-3 polyunsaturates, of which the two major components are EPA and DHA.

There is no information which suggests that salmon oil capsules are not safe. As far as intake recommendation is concerned, for the average pregnant woman, experts recommend an intake of 650mg of long chain omega-3 polyunsaturates per day, of which at least 300mg should be DHA. Thus to achieve this intake from salmon oil capsules, a daily intake of 3000mg of oil will be needed.

How does Omega-3 aid in weight watching?

The long chain omega-3 polyunsaturates can aid weight loss by enabling each of the body's cells to function in the optimal manner. Accumulation of fat is the body's response to a surplus of energy over needs.

When the reverse occurs, as in a weight loss diet, the stored energy (fat) should be liberated and burned.

However, some people appear to have a problem with this mechanism, and it has been suggested that a part of the reason for this is that the membranes which surround each of the body's cells are not functioning in the way they should because their composition is out of balance.

Cell membranes are made up largely of polyunsaturates. We now know that there are two families of polyunsaturates which are important in the make up of cell membranes: the omega-3 family from fish, and the omega-6 family from vegetable oils like sunflower seed oil.

Over the past 50 years, diets in the West have changed, to supply about twice as much omega-6, and only half as much omega-3. Thus the balance has changed.

Cell membrane composition has changed too, and some scientists think that this change in membrane composition has made it more difficult for cells to lose the accumulated fat they contain. Evidence recently published showed that weight loss was greater on a calorie-restricted diet when a small amount of fish oil was added to the diet, compared to the same diet when olive oil was added instead of the fish oil.

What are the benefits of EPA? I use this supplement for everyday and one tablet per day

EPA, or eicosapentaenoic acid, is one of the long chain omega-3 polyunsaturates found mainly in the oil from fish.

Having a small amount of EPA and its related polyunsaturate DHA, or docosahexaenoic acid, (e.g.650mg/day) is reckoned by those scientists studying this subject to be a sensible dietary goal.

This amount will provide some protection from heart disease, and perhaps cancer, depression and other common ills.

Could you give more info on products enriched with Omega-3, e.g. bread, spread, milk, juices?

The availability of ordinary foods fortified with small amounts of fish oils varies from one country to another, but in general is increasing all the time, as awareness of the health benefits of the long chain omega-3 polyunsaturates spreads.

In the Asia/Pacific region, there are milks, yoghurts, and fruit juices available containing the omega-3s. In the U.S. and Europe there are eggs, spreads, and juices available. In Scandinavia and Australia there are breads and eggs available.

In Britain at present there are only eggs with an enhanced omega-3 level.

Could you please expand on Omega-3 and psoriasis?

The relationship between psoriasis and the long chain polyunsaturates from fish oil is one which is quite well documented scientifically.

Psoriasis is one of the inflammatory diseases and increasing the amount of the long chain omega-3 polyunsaturates in the diet is known to aid in bringing about a more anti-inflammatory state.

The first trials in this area were carried out in the early 1980s and they showed that taking 10g of fish oil daily for 3 months brought about a lessening of psoriatic symptoms such as itching, flakiness and redness of skin, as well as a reduction in the amount of the body affected.

Since then, several other trials have been carried out - all showing much the same thing.

The disease is not cured by the omega-3 polyunsaturates, but it does become much easier to live with, and can be more readily controlled. Another aspect of the situation is that the omega-3 polyunsaturates can help to counteract some of the adverse effects of conventional psoriasis drugs.

What are the neurological health benefits of Omega-3?

A significant part of the structure of brain, nerves and the retina of the eye is composed of the long chain omega-3 polyunsaturates such as are only found in fish oil.

The long chain omega-3 polyunsaturates are essential for the optimal development of a healthy brain, eyes and nervous system.

Studies have shown that if the diet does not provide sufficient omega-3, then the formation and function of these vital organs is impaired somewhat.

Depression or bipolar disorder is one common condition thought to be affected by brain omega-3 levels. Studies comparing the incidence of depression in different areas of the world have suggested that depression is less common in areas where large amounts of fish are consumed.

Studies from hospitals have also recently provided another type of evidence that depression might well be linked with a shortage of the long chain omega-3 polyunsaturates from fish. Research published in the Archives of General Psychiatry (199; 56:407-412) reported the results of a study in which severe manic-depressives (bipolar disorder) patients were treated with long chain omega-3 polyunsaturates (10g/day) from fish oil.

A control group was given olive oil instead of fish oil. After 4 months, the trial was stopped because the fish oil group had improved so much that it would have been unethical to continue to deny the benefits to the placebo group.

Other areas in which the long chain omega-3 polyunsaturates from fish are thought to be involved include eyesight development in very young children, dyslexia, dyspraxia, hyperactivity, intelligence, problem solving ability, and even protection from mental illnesses such as schizophrenia.

Research on all these areas is not yet well developed, but the indications are substantial, and consistent with epidemiological observations, and the theoretical predictions of experts in these areas.

I would like to know if it's ok for children to take Omega-3 and how much?

Omega-3 is perfectly safe for children to take, though practical problems can make it difficult for children under 5.

As far as amounts are concerned, for children between 5 and 10 years of age, I suggest you try to get an intake of around 300mg per day of long chain omega-3 (from fish oil).

If you want to use vegetable omega-3, you must increase this by 10 times to have the same effect. For children over 10, I suggest about 500mg per day.

Which is better for heart health - fish or fish oil supplements?

If you are happy eating a least two good-sized portions of oil fish a week, this should provide you with sufficient omega-3 oils to maintain a healthy heart and circulation.

However, if you cannot guarantee you will eat this amount, fish oils in supplement form may be a safer option.

One piece of research conducted over two years showed that there were no differences between the effects of eating oil-rich fish twice a week and taking fish oil capsules daily for two years (DART sub-group analysis).

Supplements offer the additional benefit of supplying a measurable amount of omega-3 whereas the amounts in fish vary.

Why do doctors recommend aspirin for heart rather than fish oils?

Although a nutritional approach to heart health maintenance is better than drug treatment in most cases, there is no comparative data to show that a certain amount of omega-3 long chain polyunsaturates is as effective as routine use of low-dose aspirin in secondary prevention of heart attack, although there is certainly a body of evidence to suggest it has a role in heart health.

If aspirin is prescribed then it is important that you do not switch to fish oil supplements without first consulting your doctor.

If you are in good health, then fish oil supplementation will help keep you that way. The side effects of fish oil (improved skin condition and joint mobility to name just two) are bonuses!