Omega-3 fatty acids and mercury, both found in fish, appear to have opposite affects on heart health, according to a northern European study.
Researchers, whose conclusions were published in the American Journal of Clinical Nutrition, looked at data from more than 1,600 men from Sweden and Finland to find that men with high levels of mercury in their body had an increased risk of heart attacks, while those with a high concentration of omega-3s had a lower risk.
Fish are considered part of a healthy diet, but the balance between potential risks and benefits from the two compounds is not clear.
Researcher Maria Wennberg said that while the study can't clarify cause and effect, there are ways to get fish oil naturally without getting a lot of mercury too.
"Fish consumption two to three times per week, with at least one meal of fatty, non-predatory fish (such as salmon) and an intake of predatory fish not exceeding once a week can be recommended," Wennberg, of Umea University in Sweden, told Reuters Health by email.
Predatory fish such as shark, swordfish, kind mackerel and tilefish are at the top of the marine food chain and for that reason concentrate mercury from the environment in their tissues.
The heavy metal is known to be toxic to the nervous system, especially in fetuses and children, and the U.S. Environmental Protection Agency warns women of childbearing age and children against eating predatory fish.
The men in the study submitted hair and blood samples to measure their mercury and omega-3 levels, as well as information on their health and lifestyle.
The average mercury level among the Swedish men was 0.57 micrograms per gram of hair, and more than twice as high in their Finnish peers. Swedes, however, had higher levels of omega-3s than did Finns.
The researchers found that men with at least 3 micrograms of mercury per gram of hair had a somewhat increased risk of heart attacks compared with men with 1 microgram per gram, although they didn't calculate the exact risk.
But this only held true if the men also had low levels of omega-3 fats. For men with more of the fats, it took higher levels of mercury to see an increased heart attack risk, suggesting the two compounds might have opposite effects on the heart.
The results don't prove that the high mercury levels were responsible for the increased risk of heart attack, merely that the two are linked.
Dariush Mozaffarian, at the Harvard School of Public Health in Boston, said that other factors such as less education among those with high mercury levels could also be at work.
Previous studies by Mozaffarian, who was not involved in the new work, did not show a link between mercury and heart attacks, but that research involved mercury levels much lower than in the current study. SOURCE: http://bit.ly/PQ4CVi
Europe's top court ruled on Thursday that obese people can be considered as disabled, meaning that they can be covered by an EU law barring discrimination at work.
The greater the exposure to fine particulates emitted by fires, vehicles, and industrial smokestacks the greater the risk, found the study
Mali's last infected patient recovered and left hospital last week, while the remaining individuals who came in contact with an infected person finished a mandatory 21-day quarantine
The young man, who hails from the southern city of Khan Younis, was the Gaza Strip's first H1N1 fatality
The text appeased developing countries, including China and India, concerned that previous drafts would impose too heavy a burden on emerging economies
Global environmental umbrella organization designates country as most backward at UN climate conference in Lima.
Ship carrying 1,500 tons of food and medical supplies heads to Ebola-hit West Africa who is need of urgent medical supplies.
Peru has more tropical glaciers than any other nation but rising temperatures linked to global warming have helped shrink the ice masses by up to 40 percent
Pesticide poisoning causes inability to breathe, chemical burns, loss of reflexes, twitching, and ultimately death, experts say
The human safety trials, which began in Geneva on Nov. 10, are due to resume on Jan. 5 in up to 15 volunteers after checks to ensure that joint pain symptoms in hands and feet were "benign and temporary"
The Nazca Lines are a set of giant images of plants and animals, such as a monkey, a spider and a hummingbird, excavated in the soil some 1,500 years ago.
Experts have sounded the alarm in recent years over how plastic pollution is killing huge numbers of seabirds, marine mammals and other creatures while sullying ocean ecosystems.
Nine months into the worst Ebola outbreak on record, Ebola is still spreading in Sierra Leone and parts of Guinea.
The death toll from the Ebola outbreak in West Africa has risen to 6,331 in the three worst hit countries, with Sierra Leone overtaking Liberia as the country with the highest number of cases
A total of 140 cases of measles had been reported whilst 6 people have died from the disease according to the Egyptian Health Ministry
The Ethiopian government is in the middle of a biannual spike in malaria as it seeks to control the epidemic.