Mercury Levels in Fish

This is the VOA Special English HEALTH REPORT.

Two studies are adding to the debate about the health risks of eating fish containing high levels of the metal mercury. One study suggests that people who eat fish high in mercury may increase their risk of having a heart attack. Yet another study found no link between mercury and heart disease.

Both studies were published in The New England Journal of Medicine in November.

Mercury is a natural element. Some bodies of water have become polluted with mercury. High levels of the metal have been found in large fish, such as king mackerel, shark and swordfish. Scientists say mercury can be harmful to people. For example, it can harm the developing brain of a fetus or child. So some experts say that pregnant women should avoid eating fish containing high levels of mercury.

However, the American Heart Association and other experts have advised Americans to eat fish at least two times a week. Fish contains important substances, including omega-three fatty acids. These are believed to reduce the risk of heart disease.

Scientists at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland organized one of the new studies. They examined medical records of more than one-thousand-four-hundred men from Israel and eight European countries. They compared men who had suffered a heart attack with healthy men.

The scientists examined mercury levels in the men by studying toenail particles from the men's feet. The study found that mercury levels in the men who had a heart attack were fifteen percent higher than those with no history of heart disease. It also showed that men with the highest mercury levels were about two times more likely to have a heart attack than men with the lowest levels.

However, a study by the Harvard School of Public Health in Cambridge, Massachusetts disputes the findings. The Harvard scientists compared two groups of about five-hundred American men. All the men in one group had suffered a heart attack. The other men showed no evidence of heart disease. The Harvard scientists also examined toenail particles for mercury. They found no link between mercury and the risk of heart disease.

Many doctors say people should not stop eating fish because of concerns about mercury.

This VOA Special English HEALTH REPORT was written by George Grow.