How To Lower Irregular Heartbeat Risk?

According to some estimates, up to 9 percent of Americans will develop atrial fibrillation (AF) by the time they reach their 80s. AF is the most common heart arrhythmia (irregular heartbeat). Though it may cause no symptoms, it is often associated with palpitations, fainting and chest pain. It could eventually lead to stroke and heart failure.

AF might be treated with medications to either slow the heart rate to normal range (range control) or revert the heart rhythm back to normal (rhythm control). People with AF are often prescribed with blood-thinning drugs to prevent stroke.

A new study by researchers from the Harvard School of Public Health reported on January 26, 2012 in the journal ‘Circulation’ that older adults who had the highest blood levels of omega-3 fatty acids were 30 percent less likely to later develop an irregular heartbeat than those with the lowest blood levels of omega-3.

The omega-3 fatty acids measured in the study were eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). They can be found in oily fish and some enriched foods like eggs and in fish oil supplements.

While some previous studies have suggested that people who ate a lot of fish had a lower risk of developing AF, these studies relied on questionnaires answered by participants about how much fish they ate, which could only estimate the amount of omega-3s they consumed.

To get a more accurate measurement, the researchers sampled blood from 3,326 adults aged over 65. These participants’ health was tracked over the next 14 years (1992-2006) and 789 were found to develop AF.

Researchers’ analysis showed that those with the top 25 percent omega-3 levels in the bloodstreams at the beginning of the study were about 30 percent less likely to develop AF, comparing with those with the bottom 25 percent blood levels. Of the 3 omega-3 fatty acids, high DHA levels were linked to a 23 percent lower risk for AF, but no reduced risk was found for EPA and DPA.

Other heart experts not involved in the study cautioned that the study did not prove eating fish could lower AF risk. The study, however, did provide some idea that the fatty acids found in fish could work by stabilizing the excitability of heart muscle cells. Meanwhile, they also suggested further studies should be carried out to find out how fish oil might be used as a potential preventive measure against AF.

Why Fish Should Be On Your Diet List?

Fish, like salmon, mackerel and albacore tuna, that high in omega-3 fatty acid is good for the heart because omega-3 fatty acid could reduce the risk of coronary heart disease. Perhaps this is why American Heart Association (AHA) advice people to eat at least 2 servings of fish a week.

Despite concerns on the impact of increased exposure to mercury in fish, Swedish researchers from Umea University in Sweden argued in their paper published in November 2010 in ‘American Journal of Clinical Nutrition’ that the benefits of consuming fish still outweigh the harmful effects of mercury. However, they also advised people to avoid eating fish high in mercury, which include perch, shark, swordfish and halibut.

More than 900 Swedish men and women took part in a study that required them to answer questionnaires about the amount of fish in their diet. Their mercury and selenium levels in red blood cells were analyzed.

While the mercury levels were generally low for Scandinavians, participants who had higher mercury level in their red blood did not have a higher risk of cardiac problems. It is possible that the protective nutrients in fish offset any harmful effect of mercury at these low levels of mercury, as explained by the researchers.

Meanwhile, the researchers admitted that relying on the participants’ memories on the amount of fish consumed could have drawbacks as this could have an impact on the results obtained. They also highlighted one finding from their study: participants who had elevated traces of selenium in their red blood cells appeared to have higher risk of sudden cardiac death.

Selenium is a trace mineral that is essential to good health but only small amounts are needed. It appears to act as an antioxidant that can reduce risk of cardiovascular disease and cancer.

Nevertheless, previous findings on effect of selenium on heart were mixed. Several studies suggested risk of heart disease and stroke might be reduced by about 40 percent by an added 100 mg per day of dietary selenium. On the other hand, a study by researchers from University of Warwick found that total cholesterol levels increased by 8 percent with an increase of 10 percent in LDL (so called bad cholesterol) in participants having more than 1.2 mol/L of selenium in their blood, leading to increase in risk of cardiovascular disease.

As such, the Swedish researchers felt that the health effect of selenium should further be probed.