The advisory, which was issued in 2004, provides guidelines on safe levels of fish consumption for pregnant women and young children.
The announcement comes in response to "recent inquiries" about the Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) consumer advisory, and confirms that "fish and shellfish are an important part of a healthy diet and can contribute to heart health and children's proper growth and development."
"Because of their many healthy benefits we recommend that women and young children include them as a regular part of their diet. However, nearly all fish and shellfish contain traces of mercury," said the FDA.
Indeed, for most people, the trace levels of mercury found in fish is not a cause for concern. However, a build-up in the blood stream can lead to reproductive problems in women and affect the development of the nervous system in children.
In its announcement yesterday, the FDA suggested that women and children follow certain recommendations to ensure they receive the benefits of eating fish while reducing their exposure to the harmful effects of mercury.
These include avoiding fish known to have high levels of mercury, such as shark, swordfish, king mackerel and tilefish, as well as limiting consumption of other fish to twice a week.
There is a growing body of evidence that the omega-3 fatty acids in seafood like canned tuna are associated with good heart health, optimal brain function and cognition, improved eye and skin health, and protection against certain cancers.
A major study by the Harvard Center for Risk Analysis, confirms that the health benefits of consuming seafood outweigh any risk due to trace amounts of mercury in fish.
The study, published in the November 2005 issue of the American Journal of Preventive Medicine, concluded that for women of childbearing age, cognitive benefits can be achieved with virtually no negative impact on the developing child if women of childbearing age eat two servings a week of fish that are low in mercury.
The Harvard researchers said that if consumers reduce fish consumption out of confusion about mercury, there will be serious public health consequences, notably higher death rates from heart disease and stroke.
Earlier this month, California's Supreme Court ruled that tuna companies do not have to warn consumers about the mercury in canned fish, ending a battle by the state attorney general's office to require the labeling under the State's Proposition 65. The labeling requirement could have led to a downturn in tuna consumption and similar moves by other state governments across the US.
Judge Dondero ruled that California's Proposition 65 requirement that canned tuna include warning labels regarding the presence of mercury would do more harm than good. He ruled that the proposed legislation is in conflict with the FDA/EPA decision to issue an advisory, rather than requiring warning labels on all canned tuna. The judge ruled that FDA policy therefore preempts the state warning requirement.
In its recent announcement, the FDA said it continues to test fish and shellfish for mercury.
"Should there be a significant change in the underlying science regarding the risks from methylmercury or the benefits from fish, FDA and EPA will update the advisory to ensure that the public is informed when making choices about the amounts and types of fish to eat," it said.