Is Eating Whale Meat in Japan A Risk to Consumers' Health?

(from "ISANA" No. 22, 2000)

Milton Freeman
Senior Research Scholar at the Canadian Circumpolar
Institute. University of Alberta.

The presence of contaminants in human foods is always a reason for concern. Japanese consumers, and indeed, people in other countries around the world, know of the tragic consequences of mercury contamination of fish in Minamata Bay four decades ago.

Recently, four scientists reported that contaminant levels are dangerously high in whale and dolphin meat, blubber, and organ meats eaten in Japan. From these findings, they claim there is a "substantial human health risk" associated with eating whale and dolphin, and they call on the government to immediately "ban the sale of contaminated products". The authors admit their studies have not yet been accepted for formal publication which would require review by experts familiar with the human health risks associated with the chemicals they have identified. To assess the usefulness of these warnings directed to Japanese consumers, it may be helpful to consider the experiences in another country where similar concerns have been raised in the past by environmentalists and where contaminated whale products are also eaten.

The customary diet of native residents in the Canadian Arctic contains large amounts of animal meat and fat. Most of the people live in coastal communities, so the meat, blubber, and various organs (including the liver and kidneys) of whales and other marine mammals remain a significant component of the everyday diet of thousands of people in northern Canada, as it similarly does also in Alaska, and Greenland. Today, a wide variety of imported foods are available in these isolated communities. However, these imported foods are expensive and are also considered culturally inappropriate as alternatives to local marine mammals and fish. Recent studies in northern Canada indicate that more than 90% of northern native households continue to consume the local animals they hunt and fish.

The bodies of arctic animals contain large deposits of fat, and the fats are where many of the contaminants accumulate. It is because many arctic residents consume relatively large amounts of marine mammal fats daily that peoples bodies have shown levels of some contaminants far above levels found in people living outside of the arctic regions. These high levels are also known to be several times above the "safe levels" established by governments.

Despite its distance from industrial sources of pollution, all the pollutants found in the industrial and agricultural regions of the world are also found in the Arctic. Pollutants such as DDT, PCBs, HCH, dieldrin, and chlordane, also detected in Japanese whale products, are found in the most remote parts of the Canadian north and in arctic residents' blood, milk, and bodies. In addition, high levels of various heavy metals (such as mercury and cadmium) occur in high levels in arctic animals', and peoples', bodies.

The Canadian government and the public first became alarmed when high levels of environmental contamination were reported by scientists and journalists about thirty years ago. These reports were similar to those recently appearing in the Japanese press. As in Japan, it was widely reported that these environmental contaminants were highly toxic, occurred at levels exceeding safe levels, and would consequently threaten the peoples' health.

These scientific findings were particularly troubling to Canadian arctic residents. Many remembered the alarm caused when high levels of radioactive contamination of their food was earlier reported, at a time when atmospheric testing of nuclear weapons was taking place. It was also at that time that high levels of mercury were first reported in whale, and people were consequently advised to stop eating this favorite local food.

However, after not eating whale for a few months, people experienced great hunger for this traditional food, and resumed eating whale on a regular basis. Today, whale skin and blubber remains the most highly esteemed food among Inuit populations in Canada, Greenland, Russia and the United States, even though mercury levels in this food exceed the recommended limits set in Canada and the U.S.

Over the years since the earliest reports appeared, large numbers of scientific reports and conferences have discussed the health risks people are exposed to when consuming food containing high levels of organochlorines and heavy metals. These contaminants are regularly reported to cause developmental and neurological abnormalities, and reproductive, kidney, liver, circulatory, and immune system disorders. However, despite considerable research in Alaska, Canada, and Greenland (all regions where contaminated marine mammals are regularly consumed), the medical authorities in these countries can find no evidence of negative health effects.

Even in the absence of human health effects, the Canadian government initiated a six-year comprehensive study of this issue. The resulting 450-page Canadian Arctic Contaminants Assessment Report was published two years ago; written by more than 80 medical and biological specialists, the report includes an assessment of the health consequences of consuming foods containing various heavy metals, radionuclides, and organochlorines (including PCBs, DDT, HCH, chlordane, dieldrin and several others).

This Canadian study is relevant to consumers' concerns in Japan. One conclusion reached is that the well-known health benefits of consuming marine foods far outweigh any potential negative health consequences. The report concludes that "based on insufficient information about the risks and the significant known benefits of traditional food [marine mammal meat and fat], people were not advised to significantly alter their current diets".

In contrast to this comprehensive and careful evaluation, the recent warning to Japanese consumers says nothing about the well-known nutritional and health benefits associated with consuming marine mammal meat and fat. These known health benefits must be considered when assessing whether it is advisable to stop eating whale and dolphin meat and fat. Merely listing contaminants found in food provides no useful guidance unless related to the quantities of food being eaten and the frequency of eating it.

Environmental pollution is not news; nor is the contamination of various agricultural foods with chemical pesticides, herbicides, injected growth hormones and antibiotics. In the case of toxic heavy metals like mercury found in sea-water, this is frequently naturally occurring, derived from rocks or undersea volcanic activity and has likely existed for centuries if not millenia.

Northern Canadians individually consume considerably larger quantities of marine mammal meat and fat than do consumers in Japan. This is not surprising, for arctic residents' food choices are much more limited than is the case in Japan. Compared to earlier times in Japan, when whale meat was a cheap form of animal protein and its consumption was more frequent and widespread, whalemeat is eaten relatively sparingly by most consumers in Japan today. Reports tabled at IWC indicate that whale consumption in whaling (and nearby) communities in Miyagi prefecture a decade ago, ranged from 130 to 170 grams per household, and in Hokkaido the frequency of eating whale meat ranged from about once a week in whaling-related households to once in about ten days in non-whaling households. Individual serving sizes and the frequency of eating whale (and equally-contaminated seals) are significantly greater among Canadian arctic peoples. Although naturally-occurring mercury may remain at a constant high level in marine meats, recent research indicates most of the organochlorine pollutant-levels in the environment are decreasing at the present.

Researchers offers various explanations for the lack of clinical evidence that these chemicals are harmful to people at the levels being consumed. A World Health Organization (WHO) report indicates that mercury toxicity appears to be blocked by the presence of selenium found in whale tissues. A study completed this summer by the U.S. National Research Council finds no evidence linking PCBs, and other so-called enzyme disrupters, to any health risk. This follows a recent Government of Quebec health study that found the PCBs occurring in high concentration in mothers' milk are different from PCBs known to cause developmental problems in infants and children.

The recent Canadian government report concludes: "the public has been advised to continue eating traditional diets of fish and sea mammals and nursing mothers have been strongly urged to continue breastfeeding their babies".

People generally accept that there is some risk associated with every activity - even medical procedures like immunization or surgery carry a risk of complications or even death, as does driving a car, engaging in certain outdoor sports, and frequenting places where others are smoking cigarettes. In each case, consumers consider the benefits, as well as the risks, associated with the choices they make.

In a recent review of the causes and prevention of cancer, two distinguished University of California cancer experts, Dr. Bruce Ames and Dr. Lois Gold, observe that a cup of coffee contains over one thousand chemicals, of which more than half of those tested cause cancer in laboratory animals. As many adults around the world drink coffee several times each day on almost every day of the year during their adult lives, this might suggest to alarmists that a large proportion of adults are at high risk of developing cancer. Evidently this risk is not considered sufficient for governments to impose limits on coffee drinking. The Japanese public and government is equally advised to be cautious in reacting hastily to dangerously incomplete reports that contain no good evidence of harm or benefit to consumers who practice the commonsense virtue of eating all types of food in moderation.