(20-09-07) Taking Fish Oil Omega-3s to Heart

As several reports in this and previous issues of Fats of Life have described, the long-chain omega-3 fatty acids in fish and fish oils have favorable protective effects on the heart. One of the most striking is their ability to alter the heart?s electrical properties. They make abnormal heart rhythms more stable, lower heart rate, improve heart rate variability?a reflection of the heart?s ability to handle a changing environment?and most important, they lower the chance of sudden cardiac death. Unstable heart rhythms are the underlying cause of sudden cardiac death, the most common cause of heart-related deaths. From this snapshot, it seems desirable to have these substances stashed in our hearts.

In this study, researchers at the Royal Adelaide Hospital in Australia had the opportunity to measure the effects on heart tissue of consuming fish oil containing long-chain omega-3s or flax oil providing ALA* compared with the effects of olive oil. They wanted to know if you could raise the heart?s content of omega-3s and whether there were differences in uptake among the various omega-3 fatty acids. Fish oils contain EPA* and DHA,* which are long-chain omega-3s, while flax oil contains ALA, a medium-chain omega-3.

The patients in this study were undergoing coronary artery bypass surgery or valve repair. Prior to surgery, patients were invited to consume one of the oils for varying times (7 to 63 days) before their operation. Each of the omega-3 oils contained a large dose of fatty acids, about 6 times more than a serving of salmon. You could call it omega-3 loading! A small sample of heart tissue was extracted during the surgery and analyzed for its fatty acid content.

Prior to taking the fish or flax oil, the patients? heart tissues contained about 10 times as much DHA (4.8%) as EPA (0.5%) and very little ALA (0.1%). Within 10 days of consuming fish oil, the DHA content increased by 41% to 6.8%, while the EPA content increased to 0.9%. Thus, the heart had a strong preference for DHA over EPA and accumulated this fatty acid more quickly. After about 3 weeks, the accumulation of DHA leveled off. Consuming fish oil for a month doubled the amount of EPA and DHA in heart tissue as at the outset.

In the patients taking flax oil, the ALA content of the heart nearly tripled, but was still low (0.3%). The EPA content increased with the consumption of flax oil, but was just a quarter of the EPA content achieved by taking fish oil. DHA did not increase, confirming other reports that consuming flax oil does not raise DHA levels. Overall, consuming flax oil did not have any significant effect on the heart?s content of long-chain omega-3s.

Are these observations important? They could be life-saving because the greatest likelihood of sudden cardiac death in heart attack survivors is the one-month period immediately after a heart attack. In those weeks, the chance of sudden cardiac death is 3 times greater than during the period from 1 to 6 months after a heart attack. By taking a high dose of fish oil right after a heart attack, a person can rapidly increase the content of DHA and EPA in the heart and reduce the chance of developing unstable cardiac arrhythmias. For those not facing heart surgery, a more gradual accumulation of EPA and DHA in the heart is possible through the regular consumption of fish or fish oil supplements. Boosting one?s intake of long-chain omega-3s is worth taking to heart.

Source: Heart Health

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