The New York Time’s Blog, Green, is reporting that a new study suggests people need to be more wary of saltwater fish than freshwater fish because mercury in seawater is more likely to stay in its toxic form. 

The study may well show that mercury in seawater is more likely to stay in its toxic form, but suggesting people be concerned about eating saltwater fish is more than a stretch; it’s a colossal and scientifically unsupportable leap that could result in harm to public health.

You see, the study in question did not look at what happens when people actually eat fish.  With a bit of research, the folks at Green could have found that two prestigious panels with a combined total of 30 experts in the fields of nutrition and toxicology recently took exhaustive looks at just that.  And here’s what they concluded: 

• “Moderate, consistent evidence shows that health benefits derived from the consumption of a variety of cooked seafood in the US in amounts recommended by the Committee [at least two servings per week] outweigh the risks associated with methyl mercury (MeHg) and persistent organic pollutants (POPs) exposure, even among women who may become or who are pregnant, nursing mothers, and children ages 12 and younger.”-- Dietary Guidelines Advisory Committee Report

• “Among the general adult population, consumption of fish, particularly oily fish, lowers the risk of coronary heart disease (CHD) mortality. There is absence of probable or convincing evidence of CHD risks of MeHg.” And “when considering benefits of [omega-3s] vs. risks of [mercury] among women of childbearing age: maternal fish consumption lowers the risk of suboptimal neurodevelopment in their offspring compared to women not eating fish in most circumstances evaluated.” -- Executive Summary from the Joint FAO/WHO Expert Consultation on the Risks and Benefits of Fish Consumption

While Green tries to entice readers with its talk of toxic mercury, the fact is, “studies of fish, including tuna and swordfish that were up to 90 years old report levels consistent with today's levels”… and…“limited data suggest that methylmercury concentrations in commercial fish have not increased or decreased over time” according to a peer reviewed, published FDA draft report.

But let’s be honest, the headline “mercury concentrations in Yellowfin tuna caught off Hawaii in 1998 were found to be essentially identical to those caught in the same area in 1971 – a span of 27 years,” (another fact from FDA) isn’t too tantalizing for Green’s audience.

Journalists reporting on this study should take care to recognize this is not research about human health and trying to turn it into such is a serious sleight of hand.