• inuit
• alaska
• cardiovascular

Recently, DiNicolantonio found evidence that an increase in the intake of refined carbohydrates and sugar may have lead to the increase in the incidence of atherosclerotic disease in the Greenland Inuit.1 Thus, we sought to determine if a similar event occurred in the Alaskan Inuit, and in particular, the Alaskan Inland Inuit.

The traditional Alaskan Inuit lived a semi-nomadic life hunting and catching fish, marine mammals and birds. However, beginning around 1920, a group of Alaskan Inuit slowly developed a permanent settlement in the mountains coming to live in Anaktuvuk Pass in 1950.1 In 1953, a post office was established as well as a ‘white trader’ store. Bang and Kristoffersen of the Gade Institute from the Department of Pathology and School of Dentistry in Norway performed two studies from two different time periods on the diet and dental health of the Alaskan Inland Inuit. They analysed the diet in 1955–1957 by ‘weighing of all the food eaten by each person for two consecutive days once a month during a 2-year period. At that time, samples of the food were analysed in order to determine the content of fat, protein and carbohydrate, as well as the total caloric intake of each individual’.1

In 1965, the dietary intake was conducted by the ‘interview method’ plus personal observations when visiting all of the families during meal times. Bang and Kristoffersen ‘…contacted all of the Eskimos involved in the study questioning each individual in detail about what food and roughly how much of each food item he consumed in the course of the year’.1 The authors noted a dramatic increase in carbohydrate intake of ‘nearly 50%’ and a decrease in the intake of protein ‘by about 50%’ from 1955 to 1957 to 1965.1 This rise in the intake of carbohydrate was paralleled by an ‘almost 90% increase’ in the sum of decayed, missing and filled permanent teeth for primary teeth (from 3.0 to 5.6) and a fourfold increase in those >6 years old, ‘the percentage of caries-free persons had decreased from 74.5% to zero in 8 years…While 50% of the children in 1955–1957 had caries-free primary teeth all the children had decayed teeth in 1965…The most dramatic change was observed in individuals 30 years of age or older. In this previously caries-free group, all subjects had developed caries in 1965’.1 Thus, the Alaskan Inland Inuit that had subsided on a diet virtually devoid of carbohydrate for most of their life who did not have any dental caries between 1955 and 1957 had all developed dental caries by 1965; in the interim, the intake of carbohydrate had increased by 50%.1

Bang and Kristoffersen elaborated on how the Alaskan Inland Inuit diet changed, ‘While previously all able men in the village frequently were out hunting, trapping and fishing, only a couple of the young men were still actively engaged in such activities in 1965. Manufacture of souvenirs had proved more profitable and the income financed the purchase of refined foods from the local stores. Consequently, only some 20% of the food intake was made up of native foods, mainly caribou meat. Hunting was now mostly limited to the short periods when the caribou came close to the village. In 1955–1957, the percentage of calories obtained from protein and fat was high while the percentage derived from carbohydrate was low. In 1965, the intake of protein was about 50% lower (carbohydrate intake was 50% higher)’.1 These details highlight the fact that these Eskimos were no longer subsisting on their native diet but instead a diet much higher in refined carbohydrates.

Importantly, the Anaktuvuk Pass Inuit of 1965 were ‘living under the same environmental conditions as far as geographical location, climate, housing and clothing is concerned’1 compared with those from 1955 to 1957. Thus, the most dramatic environmental change in these Alaskan Inland Inuit during the 8-year study period was the change in their diet. The dental examinations in each time period were carried out by the same investigators using a similar method under identical conditions and it was said by these authors that an overestimation in the prevalence of dental caries in 1965 was highly unlikely as around half of the subjects were radiographed for dental caries in 1955–1957, whereas radiographs were not used in 1965. Thus, among the Alaskan Inland Inuit of Anaktuvuk Pass, an increased intake of refined carbohydrate of at least 50%, and in some estimates as much as 200%, was closely linked to a tremendous rise in dental caries.1

‘The Eskimo race is generally believed to have a low incidence of cardiovascular disease (Wilber and Levine, 1950), although their diet is apparently high in fat and cholesterol’.2

Apparently, a diet high in fat and cholesterol did not seem to have negative cardiovascular consequences for the Alaskan Inuit. Rodahl published a scientific paper in 1955 on the Alaskan Inland Eskimo indicating a daily caloric intake of 2700 calories, 37% of which was fat (105 g of fat per day).2 Another larger survey found that ‘…the average daily fat consumption in Alaskan Eskimos was 139 g (40% of the calories)’.2 And the mean cholesterol intake was 340 mg daily (varying from 150 up to 700 mg per day).2 These estimates were considered underestimates because the cholesterol content of certain foods was unknown at the time. Rodahl wrote, ‘It may also be noted that the cholesterol intake varies greatly from one Eskimo group to another, depending on the different dietary habits. Thus it was observed that among the inland Eskimos, the Nunarniuts at Anaktuvuk Pass, some of the men consumed as much as ≥70 g of boiled brain from mountain sheep in a single evening meal yielding almost 600 mg cholesterol from this food item alone’.2

Rodahl went on to write, ‘In a survey of 104 Alaskan Eskimos the author found that both the systolic and diastolic blood pressures were lower in Eskimos than in Whites of corresponding age. Eighty per cent of the recorded systolic blood pressures were <116 mm Hg and no systolic blood pressure >162 mm Hg was ever recorded in our ‘normal’ Eskimo subjects. In a series of 117 Eskimo patients, only one of the patients had systolic blood pressure >145 mm Hg’. Thus, the rate of hypertension in Alaskan Inuit appears to be virtually non-existent (1/117 being around 0.85%) and about one-tenth the rate compared with that in the USA at the time.

Rodahl also noted that, ‘None of the 16 Eskimos analysed here showed any evidence of arteriosclerosis by clinical or roentgenological (X-ray) examination, and cardiovascular disease was extremely rare among the large number of Eskimo patients examined by the author during a 2-year period in Alaska’.2

Based on chest X-rays, Rodahl also noted, ‘Of the entire material, one Eskimo showed calcium deposits in the arteries’.2 While it is hard to know based on the paper whether this was out of 84 Inuit or the 9 natives who were older than the age of 47 years, to err on the side of caution using the 9 natives, indicates that calcium deposits in the arteries of the Alaskan Inland Inuit (>47 years old) were at most 11%. However, the prevalence of arterial calcifications in more westernised countries for those of similar age (40–49) is approximately 50%.3 This suggests that Alaskan Inuit had around one-fifth the prevalence of arterial calcifications. As calcium deposits in the arteries generally indicate more advanced atherosclerotic lesions, and since the Inuit apparently had a lower rate of calcifications, this may explain the lower rate of clinical cardiovascular disease based on autopsy. Indeed, it has been suggested that plaque rupture occurs at the interface between calcified and non-calcified sections of atherosclerotic plaque.3 Thus, it can be argued that a low rate of arterial calcifications in the Alaskan Inuit may have offered them protection from plaque rupture. Table 1 summarises the effects of a western diet on the health of the Alaskan Inland Inuit.