Pregnant women in the U.S. are being advised to avoid eating canned tuna because it may contain harmful levels of mercury.
Consumer Reports is a magazine aimed at the American consumer and is recommending far more caution than suggested by the U.S. government.
According to the magazine, government tests found instances when canned light tuna had as much of the potentially harmful heavy metal as white tuna, which is called albacore.
The Food and Drug Administration has said that high levels of mercury in the bloodstream may harm developing nervous systems and fish and shellfish are the main sources of mercury exposure for humans.
As far back as March 2004, the FDA and the Environmental Protection Agency were recommending that women who are pregnant, planning to become pregnant, nursing or feeding a young child should eat no more than 6 ounces (170 grams) of albacore tuna a week.
But the government also says it is safe to eat up to 12 ounces (340 grams), the amount of fish in two meals, per week of fish and shellfish low in mercury, such as shrimp, salmon, light tuna, catfish and pollock.
However Consumer Reports says 6 percent of canned light tuna tested by the FDA contained at least as much of the metal and in some cases more than twice as much, as the average can of albacore.
Consumers Union, which publishes the magazine says because of concerns that both types of tuna showed instances of higher levels of mercury, it decided to recommend pregnant women eat neither.
The FDA Center for Food Safety and Applied Nutrition has apparently told the magazine there is no significant risk from the occasional can with higher levels of mercury.
The American Journal of Preventive Medicine (2005. 29[4] 325-334) has published a study concluding that if all adults reduced their fish consumption by 17 percent, an additional 9,500 would die from vascular disease.
The U.S. Tuna Foundation trade group (USTF), has accused the magazine of over-reacting to a minor problem and paying the public a great disservice.
The foundation says the health benefits of seafood easily outweigh the risk posed by "trace amounts of mercury" and that view is supported by sound scientific research.