Fishing about and about fishing

              

Whether to stop eating fish suspected of mercury contamination and forfeit the benefits of Omega-3, or rather ignore the mercury content and keep eating fish, because those benefits outweigh the risks involved, represents an ongoing, nagging argument.

 

The mercury scare originated in the tragedy of Minamata, Japan, where people in the area consumed large amounts of seafood heavily contaminated with industrial effluents containing  mercury compounds that, during some 35 years were being dumped into Minamata Bay. Over 3,000 victims have lost their lives, suffered from physical deformities, or have had to live with the physical and emotional pain of "Minamata Disease”. Their nervous systems were degenerating, their limbs and lips getting numb, their speech slurred. Many had their vision affected, and even serious brain damage. There had been more ghastly symptoms among both people and animals that had been exposed to the pollution.

 

The fish from Minamata Bay had had mercury concentration in their flesh of 50 ppt (parts per million), which is around 100 times what is usually found in fish, and the people who had ate them - up to twice that figure. Although, Minamata was a single, exceptional case, its horrors are still throwing their shade over our present considerations.

 

Tuna, swordfish, shark, and some marine mammals at the top of the food chain tend to accumulate mercury. The older is the animal and the closer it occurs to sources of mercury in the sea, such as e.g., volcanic activity or industrial effluents, the higher would be mercury content in its flesh. Mercury levels in such fish may happen above what’s considered safe by EPA and FDA in the USA, or some European standards. Consequently, warnings are issued, sometimes quite alarmist ones.

 

Last May, an old friend, Dr.Witek Klawe, formerly with the Inter-American Tropical Tuna Commission, sent me the following information that clarifies the mercury-in-fish problem.

 

According to “Talk of the Nation” programme at the National Public Radio in America,  the U.S. National Academy of Sciences in its attempt to put some order in all the scientific and unscientific noise about fish and mercury, has warned of a risk that women who consume large amount of seafood during pregnancy may cause their children “to have to struggle to keep up in school”.

 

Not exactly, according to Dr. Gary Meyers, who was interviewed on the above programme. Dr. Meyers is a pediatric neurologist and a professor of neurology, pediatrics, and environmental medicine, and has for many years investigated this problem, with particular attention to children.

 

Dr. Meyers and his associates went to the Seychelles.  In parallel, Harvard’s scientists went to the Faeroe Islands. In both, there’s very high fish consumption and high levels of mercury in the hair of people. 

 

The Seychelles children have been eating fish in average 12 times a week that is ten times as much as is common in the USA. Also, their hair levels of mercury of almost 7 ppm (part per million) have been about ten times the average in the USA, as well. They were examined on 6 occasions with extensive neurological, psychological, behavioural and some other sorts of tests comprising their IQ and various aspects of performance and achievements. Actually the Meyer’s team used almost every test that had been used in any other study of mercury or other toxins. 

 

Their conclusion so far is that there’s no consistent evidence of any adverse effects from mercury exposure from fish consumption at the levels characteristic of those of Seychelles’ children. While there may be a worldwide general increase in ADD, ADHD, and other kinds of childhood disorders, nothing of this sort was found in the Seychelles in association with fish consumption and mercury levels.

 

Asked about a study from Harvard showing that in the Faeroes high levels of mercury passed from mother to child in utero produced irreversible impairments to specific brain functions in children, 

Dr. Meyers pointed out to some important differences. While in the Seychelles the women eat fish, in the Faeroes they seasonally also eat whale meat. Whale meat has quite high levels of mercury as well as multiple other contaminants, which are not present in fish, such as PCBs, cadmium, dioxins, and a variety of others. Thus, unlike the Seychelles, there is a periodical high-level contamination. This is a rather complex situation that must be taken into consideration when trying to draw conclusions.

 

Moreover, the Harvard study covered only slightly over 100 children, a relatively small cohort for a convincing statistical assessment. Also the association found between consumption level and adverse consequences has been rather marginal, such as for example, a measured difference of  “one finger tap in 15 seconds, between those children who had the higher exposure and those who had the lower exposure, hardly a developmental disability, a learning disability, or a mental retardation”. 

 

Actual mercury poisonings before birth resulted from poisoning episodes – said Dr. Meyers – and the majority of less than 100 such episodes worldwide have been from the consumption of grain. This because of treating seed grain with methyl mercury, and occasionally people would eat such grain. Only one case of methyl mercury poisoning ever occurred in the USA or been reported in the medical literature.

 

The study indicates that in some respects, like athletics, children were doing even better in Seychelles than elsewhere. These children might be benefiting from the high levels of Omega-3 in the seafood they consume.

 

In any case, while we may still argue about mercury in the large predators, we can safely get our Omega 3 supply from small pelagics, such as herring, sardines, sprats and mackerel, as well as salmon. The Omega 3 fatty acids are of great importance in prenatal food and during the growing years of children, because being important building blocks of the human brain, which to a large extent is made of fatty acids, they provide proven benefits to children’s neural development. Dr. Meyers recommends all, especially children, including his own, to stick to the fish diet.