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There has been a long-standing ‘merry go round’ of opinions on the value of consuming fish for heart health. Recent research studies are increasingly clarifying the real contribution that fish oil might have on heart health. It has long been observed that people consuming fish as a regular part of diet tended to suffer less heart attacks and sudden deaths related to heart rhythm problems. Further research suggested the relationship between a kind of fat present in fish called ‘Omega 3 fatty acid’ and the benefits seen from fish consumption. This has led the American Heart Association to recommend that healthy adults eat at least two servings of fish per week.
Health benefits of eating fish in addition to acting as a source of Omega 3 fatty acids:
- For those who need to eat meat, fish offers equal amounts of high quality protein on a gram to gram basis when compared to any other meat, but, at significantly lower calorie content. This can reduce the risk of obesity.
- Fish are low in sodium, but high in potassium, vitamins and other minerals. This can help lower blood pressure.
- Fish are generally low in cholesterol and saturated fats which in turn help to lower risk of heart attack.
People who consume fish have increased protection against blood clot formation and irregular heart beats. These in turn translate into reduced risk for heart attacks and sudden death due to irregular heart beats. A recent research study conducted by Dr Mozaffarian at the Brigham and Women’s hospital in USA, studied 5,000 men and women above the age of 65. The participants were asked about their frequency of fish consumption and the types of fish they ate.
What the study found was that eating fish was associated with a lower heart rate, a slower interval between when the heart received a signal to pump blood and when blood was pumped, and a lower likelihood that the heart would take a long time to re-set its electrical system after a beat.
The heart re-sets its electrical activity after every beat. When there is heart disease, the re-setting can be delayed and could be dangerous. Animal studies have indicated why the Omega-3 fatty oils confer their beneficial effect. The fish oils get into the membrane of heart cells and affect the function of their protein channels. Potassium, sodium and calcium pass through those channels, controlling the whole electrical cycle.
While the new study found that the more fish consumed, the greater the benefits, most gains were achieved with just one or two meals of fish a week.
There are caveats to consider prior to jumping on the fish bandwagon:
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Genuine concerns exist over the increasing mercury content in fish caught at the present time. Electric power producing plants all over the world emit mercury which is drained into waterways. This mercury finds its way to the fish breeding grounds. High mercury levels in fish could translate into high mercury levels in the consumers and raise the potential for toxicity, especially to developing foetuses in pregnant women. In developed countries, the mercury level in fish breeding grounds is monitored. But, in countries like India, the quality control measures need further refining.
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Not all fish have high content of Omega 3 fatty acids. Fish like salmon, trout, tuna and mackerel are rich sources and are preferred. So, know your fish type before you consume them.
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The kind of fish preparation impacts the benefit level. Fried fish do not carry the same benefits as boiled fish.
Are there benefits to consuming fish oil supplements instead of fish?
The role of fish oil supplementation is highly uncertain at this point. While earlier studies seemed to suggest some benefit, recent studies have raised serious doubts over the early results. The consensus at this time is that fish oil supplementation is not to be preferred.
What if I am vegetarian? Can I not get the benefit of Omega 3 fatty acids?
There are vegetable sources of a slightly less potent form of Omega 3 fatty acids called alpha-linolenic acid. This is found in soybeans, canola, walnuts and flax seeds. While these will not equate to benefits from fish, the benefits of Omega 3 fatty acids can still be obtained.
So, if you take care with the quality, type and mode of preparation of fish, the benefits to your heart health could be additive to all other good living habits.
Dr G Balachander
Cardiologist
Illinois, USA
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