Tag Archives: oily fish

Fish oil health benefits not clear, says new study

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London: A new study by the published online by the British Medical Journal today doesn’t find evidence of a clear benefit of omega 3 fats on health.

These findings do not rule out an important effect of omega 3 fats, but suggest that the evidence should be reviewed regularly, say the researchers.

Consumption of long chain omega 3 fatty acids, found in oily fish and fish oils, and a shorter chain omega 3, found in some plant oils, is thought to protect against heart disease. UK guidelines encourage the general public to eat more oily fish, and higher amounts are advised after a heart attack.

Researchers analysed 89 studies (48 randomised controlled trials and 41 cohort studies) to assess the health effects of long and short chain omega 3 fats on total mortality, cardiovascular events, cancer, and strokes.

Each study involved a treatment group and a control group and investigated the effect of omega 3 intake on health for at least six months. Differences in study quality were taken into account to identify and minimise bias.

Pooling the results showed no strong evidence that omega 3 fats have an effect on total mortality or combined cardiovascular events. The few studies at low risk of bias were more consistent, but they also showed no effect of omega 3 on total mortality or cardiovascular events.

When data on long chain omega 3 fats were analysed separately, total mortality and cardiovascular events were not reduced. No study showed increased risk of cancer or stroke with higher intake of omega 3, but there were too few events to rule out important effects.

Other recent reviews of omega 3 trials found that omega 3 fats decrease mortality, but the publication of a large contradictory trial has changed the overall picture. The authors cannot say exactly why the results of this trial differ from the other large studies in this field.

They therefore conclude that it is not clear whether long chain or short chain omega 3 fats (together or separately) reduce or increase total mortality, cardiovascular events, cancer, or strokes.

UK guidelines advising people to eat more oily fish should continue at present but the evidence should be reviewed regularly, say the authors. However, it is probably not appropriate to recommend a high intake of omega 3 fats for people who have angina but have not had a heart attack.

To understand the effects of omega 3 fats on health, we need more high quality randomised controlled trials of long duration that also report the associated harms, they conclude.

We are faced with a paradox, says Eric Brunner in an accompanying editorial. Health recommendations advise increased consumption of oily fish and fish oils. However, industrial fishing has depleted the world’s fish stocks by some 90% since 1950, and rising fish prices reduce affordability particularly for people with low incomes.

Global production trends suggest that, although fish farming is expanding rapidly, we probably do not have a sustainable supply of long chain omega 3 fats, he warns.

Fats

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Even though low-fat foods have never been more popular, fat or lipids are essential to our bodies and skin. In fact a lack of them can cause fast ageing of the skin. It should also be noted that heating oils destroys essential fatty acids (EFAs) and if it is smoking hot it becomes carcinogenic (cancer causing).

Bad fats – saturated (hard) fat is found in dairy products and meats. These cause obesity, heart disease, strokes and other illnesses and not necessary for the body. The fat deposits itself in arteries as well as causing weight problems.

Hydrogenated (hardened) fats are liquid fats that have been converted into solids, producing trans fatty acids, which increase blood cholestrol. Many margarines have been hydrogenated and the fat is also found in processed foods. TFAs are linked to heart disease and some cancers

Good fats – unsaturated – contain Essential Fatty Acids and oil the skin from the inside out protecting it against fine lines and wrinkles and lowering cholestrol. They also transport vitamins A, D, E and K around the body. EFAs are found in cold pressed oils, nuts and seeds and oily fish.

The EFA Omega-3 contains three different fatty acids EPA, DHA and ALA and is found in oily fish such as sardines, herrings, mackerel, tuna and salmon, linseeds, walnuts, walnut oil, flax seeds and oil; Omega-6 sunflower and seasame seeds, safflower, soya and linseed.

Studies suggest that an increased consumption of Omega 3, for example, may have positive health benefits, including a healthy heart, supple joints and enhanced learning and concentration in children. It also helps build the brain and eyes.

Souces of Omega 3 include:

Oily Fish

Oily fish is the best source of this vital nutrient. A 150g portion of mackerel or kippers provides 3g of EPA/DHA and you should eat two to four portions of oily fish per week. Girls and women of reproductive age are advised to eat slightly less because of potential pollutants in the fish.. Other good oily fish include salmon and trout, tuna and herring.

Eggs

Eggs contain small amounts of longchain fatty acids (mainly DHA) but not enough to be a good source. Omega 3-enriched eggs are excellent for boosting intake.

Fruit juice

You will not get any from normal fruit juice but some now have added oils.–

Tinned fish

Choose fish with the whole of the body such as sardines, salmon, mackeral and pilchards. Tuna is not so good because most of the oil has been removed.

Milk

Organic milk can be up to two-thirds higher in Omega 3 ALA due to the cows’ clover-rich diet.

Cereal Bars

Many are now enriched with Omega 3 are a great idea for people who do not like oily fish.

Walnuts

Although nuts may be high calorie they contain some good fats, particularly ALA.

Flax seeds

Flax seeds and oil contain a high proportion of ALA. Eaten with thefibre they helo to maintain bowel regularity as well as good blood sugar and lower cholesterol levels.

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