Current evidence suggests that Eskimos (native American Alaskans) have an increased risk of hypertension than non-native Americans living in Alaska. The reason for this is not clear, but evidence suggests that it may involve changes to the habitual diet of the Eskimos in combination with a particular genetic trait. Traditional Eskimo diets revolved around consumption of marine foods, and this provided a high intake of omega-3 fatty acids including eicosapentaenoic acid (EPA, C20:5 (n-3)) and docosahexaenoic acid (DHA, C22:6 (n-3)). In particular, it has been reported that certain groups of Eskimos have abandoned their traditional high protein, high fat, low carbohydrate diets and are now consuming high carbohydrate diets. It has been suggested that the Eskimos are more negatively affected by the typical American high carbohydrate diet and one consequence of this is that they may develop higher rates of hypertension. This negative health effects may stem in part from the genetic makeup of the Eskimos.
Researchers1 have investigated the factors that modify the association between marine food intake and hypertension. This was done by using markers for marine food intake, like the nitrogen isotope ratio in red blood cells, which has been shown to be a reliable way of estimating previous marine food intake. Using this method, the researchers observed an inverse association between marine food intake and systolic blood pressure for male Eskimos who were non-obese. However, the inverse association between diastolic blood pressure and marine food intake was present in non-obese individuals from both sexes. These results therefore suggest that genetic factors (sex) do play a role in the modification of the risk of hypertension in Eskimos. It also suggests that obesity is a modifier of the association between marine foods and hypertension in Eskimos. This supports the view that obesity is a disorder characterised by metabolic dysfunction and that this can modify normal blood pressure lowering effects of fish oils.
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