Dietary transition and contaminants in the Arctic: emphasis on Greenland

Abstract

The purpose of this review is to evaluate the nutritional qualities of the Inuit traditional food pattern seen in an evolutionary and historical perspective, and to describe the present day nutritional pattern as influenced by dietary transition. Observed exposure levels to contaminants, and their potential negative effects will be discussed. Finally, we attempt to indicate what could be the direction for future developments in order to conserve the cultural and nutritional values of the local diet, and at the same time reduce contaminant exposure levels. ... In Greenland ... the hunting culture continued well into the 20th century, with meat and organs from marine mammals, especially seals, being staple foods. ... Shortly after World War 2, local food accounted for 50% or more in the Greenlandic diet. Since then, this percentage has declined drastically, and is now on the average of around 25% in districts with the highest intake of traditional food, while in districts with the lowest intake of traditional food it is now below 10%. ... Obesity is, today, of epidemic proportions in most areas of the world, including the Arctic, and the tendency is increasing. ... Environmental contamination on a global scale is essentially a post World War 2 phenomena .... Marine food webs may be long, involving several trophic levels .... For this reason, food contamination is primarily a problem linked to intake of predatory marine mammals and seabirds. Contaminants of highest concern include PCBs, pesticides, and mercury. In addition, a number of organic compounds, such as PCBs and a several pesticides are soluble in fat and therefore concentrate primarily in fatty tissues such as the blubber, whereas mercury (as methylmercury, the chemical form that is most prevalent in living organisms) is found primarily in the muscle tissue. ... In Greenland, a relationship between contaminant exposure and sperm motility and activity of sex hormones has been demonstrated which may have implications for human fecundity. ... In order to improve the quality of food and reduce the exposure to contaminants there seems to be an immediate need for some degree of intervention in Arctic populations experiencing rapid dietary and cultural transition. ... With regard to fat, the intake of saturated fat should be restricted to a minimum and if possible replaced with monounsaturated fat .... Also the intake of plant oils (n-6) should be restricted in relation to fish oil (n-3) to ensure an n-3/n-6 ratio of above 0.2, but blubber intake from marine mammals should be reduced. With regard to carbohydrates, the intake of refined sugars, especially fruit sugar (fructose) should be restricted to a minimum, and refined starches should be eaten in moderation, vegetables and fruit intake should be increased. With regard to protein, the main part should be derived from lean red meat from terrestrial game and from fish. Because of their contaminant load meat, blubber and organs from marine mammals should be eaten in moderation, especially by children and people in the fertile age group. ... Human exposure to hazardous contaminants can be reduced in two ways: [1] Agreement of measures such as international conventions to eliminate or reduce production and use of the most dangerous chemicals. This is, however, a very slow and time consuming process. [2] Implement intervention strategies locally, in order to protect the highest exposed populations, as a quick and effective first action. ... In the Arctic, the main source of most contaminants of concern in highly exposed groups is from consumption of marine mammals. Consequently, the most efficient way to reduce human exposure is to replace consumption of highly contaminated marine mammals with fish and terrestrial mammals. ... Eating traditions are an integrated part of a culture. Cultures are not static but must constantly develop and adapt to the changing world - as must dietary habits.