Fish is good for you, almost always...

Fish is good for you. Well, some fish, some of the time. Pregnant women especially are advised to eat the stuff. That said, along with small children under three, they should avoid species with high mercury content such as swordfish and red tuna (canned has especially high levels).

A simple enough message, but as the recent media brouhaha over the findings of AESAN, the Spanish Food and Nutrition Safety Agency, regarding mercury content in fish shows, it is easy to alarm the public.

"Sometimes it is surprisingly hard to transmit certain ideas clearly to the public," says Ferran Ballester, the co-director of an INMA, an ambitious nationwide study into nutrition during pregnancy and the first years of infancy. As with the findings of a UN-related research body a couple of months ago over the possible dangers of brain cancer from cell phone use, AESAN now finds itself accused of alarmism over the issue of mercury in fish.

"If there is mercury in certain fish, we have to say so," says one researcher

Warnings should just focus on large fish, and those with high fat levels, he adds

"This type of information has to be made public by following certain procedures, and above all, the message has to be clear, and the information contained in it must be based on scientific research," says Ildefonso Hernández, the director general of Public Health under former Health Minister Trinidad Jiménez. "Any warning that is issued should be followed up with an evaluation of the health impact that the risks suppose." In other words, the information has to be useful.

By following these guidelines, there is no danger of spreading unnecessary alarm, he says. "We have to inform people, and avoid paternalism. People will not succumb to panic if the information that is provided is easy to understand, and above all, correct."

The latest controversy over how to keep the public informed of possible health risks echoes that in May, when the International Agency for Research on Cancer (IARC), an arm of the World Health Organization, published a report based on more than a decade of long-standing research into cellphone radiation, reaching the conclusion that it might lead to brain cancer. But the announcement has puzzled many health officials, who questioned its timing, saying it raised more questions than it answers.

Leaving aside what he calls the "disproportionate theatricality" with which the cellphone warning was issued, Hernández says it had no value because it provided no guidelines on what the public could do to avoid health risks. "When it comes to public health, one should always show an enormous respect for the principle of proportionality," says Hernández.

But the AESAN case is different, he says. Not only have the risks been highlighted, but recommendations on what to do to reduce the risks have been given. So can we assume that the message has been successfully put over? Well not quite. Because the information on which kinds of fish pose a risk and who should not eat them was only to be found on a website accessed through different links from consumer protection organizations.

Health Ministry officials defend their approach, saying that the different websites of regional health authorities are the "traditional channels for the transmission of any type of information of public interest," and above all, "in the case of recommendations about food consumption that are known internationally by the scientific community, rather than warnings about specific localized dangers to public health." The Health Ministry says the fact the media picked up on the story about fish and mercury from its websites "shows the ministry's website has worked as a way of transmitting information efficiently."

Carolina Moreno, who teaches journalism at the University of Valencia, and is the author of a book on communicating health and science information in the digital age, begs to differ.

"The web page of an institution is not the place to post relevant information, because only people with a well-developed understanding of the issues involved will go there. Most people are passive when it comes to this type of information. If the information is not made public, most people will be unaware of the risks they are being exposed to," she says.

Moreno speculates that the information about the risks of mercury and fish were not made more widespread "to avoid the impact on certain sectors of the economy." Much of the criticism about the way that AESAN has handled the matter has come from the Spanish Fishing Federation and other bodies representing fishing interests in Spain.

The Health Ministry stands accused not only of a bungled communication strategy, but for hiding a report produced in 2003 by the Spanish Oceanography Institute at the behest of the Environment Ministry on the presence of arsenic and other heavy metals in fish and seafood.

Here's the back story: in 2003, Spain's Spanish Institute of Oceanography (IEO) conducted a large research study that documented levels of mercury and other heavy metals in large fish such as various sharks, swordfish and bluefin tuna.

The results of the study were not good: 62.5 percent of the 128 mako shark samples and 54.2 percent of the swordfish samples contained high, unpermitted levels of mercury. Despite this alarming evidence, the results were never released due to concerns about its possible impact on the fishing industry.

Although Spain's Ministry of Environment had no qualms hiding the worrisome results from the public, environmental NGO Oceana immediately took action. After more than three years of pressure from Oceana, Spain's National Court finally relented and released the full document to NGOs and the public alike.

"In light of the data included in the study, women of child-bearing age and children can now avoid certain types of fish that could lead to mercury poisoning and neurological defects. In the United States, many supermarkets have agreed to post warnings about mercury levels, and Oceana is hopeful that Spanish supermarkets will follow suit," says Oceana on its website.

The debate on how best to communicate health messages to the public is very much open. Between posting information on a website visited only by the better-informed among us and the theatricality that Hernández accused the IARC of resorting to, there must lie many other possibilities.

But it is also true, as Hernández points out, that the Spanish health authorities "have not addressed the issue of chemical contamination as thoroughly as it should have."

Ferran Ballester agrees. "It is possible we have drawn a veil over the presence of these contaminants in fish for too long," he says, adding: "If there is mercury in certain fish, we have to say so, there is no point in hiding it."

Transparency and effective communication regarding scientific findings such as the presence of heavy metals in fish is not only important to the general public, but also when it comes to making policy decisions about public health.

Ballester cites the example of lead, which if ingested by babies, can delay brain development. Between 1976 and 1980, 90 percent of US children were found to have higher than World Health Organization-recommended levels of lead in their blood. This lead to a ban on the use of lead in gasoline, which in turn led to a dramatic fall in lead levels in children's blood by 2004. The measure was highly effective, with the prestigious Environmental Health Perspectives magazine rating the measures among the most beneficially impactful on the US economy, leading to vast savings in health care costs.

Mercury can affect the development of the central nervous system, which is at its prime growth rate up to the age of three years. This is why the Spanish Health Ministry recommends that pregnant women and children aged under three should not eat swordfish or red tuna, species that because of their size accumulate mercury and other contaminants found in water in larger amounts.

Ballester says that in general, fish is good for pregnant women, thanks to its high levels of Omega 3, phosphates, and essential proteins. He adds that health warnings should be focused solely on large fish, and those with high fat levels.

"The United States is still suffering from the consequences of the confusion created in the 1980s and 1990s when pregnant women were told to avoid fish in general. He points to the evidence collected in Spain that shows children whose mothers ate fish during pregnancy registered higher levels of brain development.

In any event, Ballester says it is not the fish themselves that are to blame, but growing levels of mercury in the sea as a result of industrial pollution. In 2009, the United Nations Environment Program called attention to the problem and the need to introduce stricter controls to reduce the levels of metals in the environment.