13Carbon and 15nitrogen isotopes in autopsy liver tissue samples from Greenlandic Inuit and Danes: consumption of marine versus terrestrial food.

BACKGROUND/OBJECTIVES: The content of (13)C and (15)N isotopes is higher in marine than in terrestrial food. (13)C and (15)N in human tissue therefore reflects the relative proportions of marine and terrestrial food consumed by the individual. The objective of this study was to measure (13)C and (15)N in liver tissue from Greenlandic Inuit and Danes. SUBJECTS/METHODS: Normal liver tissue was obtained at autopsy in 1992-1994 from 60 Inuit with a median age of 61 years (range 25-83) and in 1986 from 15 ethnic Danes with a median age of 84 years (range 66-93). By sieving, liver tissue was separated in a 'cellular fraction' and a 'connective tissue fraction'. (13)C and (15)N in dry liver tissue was measured on a mass spectrometer. delta(13)C indicates the (13)C content relative to the IAEA-CH-6 reference standard. delta(15)N indicates (15)N content relative to the atmospheric nitrogen reference standard. RESULTS: Inuit: median delta(13)C was -21.2 per thousand in cellular and -20.0 per thousand in connective tissue fractions (P=0.001). Median delta(15)N was 10.6 per thousand in both cellular and connective tissue fractions. Body mass index was negatively correlated with delta(13)C in the connective tissue fraction (r(s)=-0.42, P=0.057). Danes: median delta(13)C was -27.0 per thousand in cellular and -24.3 per thousand in connective tissue fractions (P=0.11). Median delta(15)N was 9.5 per thousand in cellular and 8.9 per thousand in connective tissue fractions (P=0.5). Inuit had higher delta(13)C than Danes in both cellular and connective tissue fractions (P<0.001) as well as higher delta(15)N in the cellular fraction (P=0.01). CONCLUSIONS: Inuit showed considerable variation in the ratio between marine and terrestrial food consumption, reflecting a vanishing hunter culture where elderly Inuit still adhere to the traditional hunters food with a high content of marine food, whereas the younger urbanized Inuit population consume food with a lower content of marine food and a higher content of terrestrial food. Danes consumed food of almost exclusively terrestrial origin. The present (13)C and (15)N analyses are in accordance with the dietary patterns obtained by dietary surveys.

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. III. Zinc measured by X-ray fluorescence spectrometry.

The aim of the study was to measure the content of zinc (Zn) in liver tissue samples from Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver samples from Danes. Normal liver tissue samples was obtained at autopsy from 50 Greenlandic Inuit (27 men) with a median age of 61 years (range 23-83) and from 74 Danes (44 men) with a median age of 60 years (range 15-87). In the entire series, liver zinc content in Inuit was not significantly different compared with Danes. There was no significant gender difference in liver zinc content either in Inuit or in Danes. The content of zinc given as median (5-95 percentile) was in Inuit 3.809 mmol/kg dry liver (2.355-7.406), and in Danes 3.992 mmol/kg dry liver (2.499-8.645). There was a significant, positive correlation between liver zinc content and age in Danish women (r(s) = 0.43, p = 0.02), which could not be demonstrated in Danish men or in Inuit. Median hepatic zinc index (zinc content in mmol/kg dry weight divided by age in years) in Inuit was 0.073, and in Danes 0.080 (p = 0.3) without any significant difference between the two genders. In Inuit and Danes there was an inverse correlation between hepatic zinc index and age both in the two genders and in the entire series: Inuit: r(s) = -0.62, p < 0.0001; Danes: r(s) = -0.70, p < 0.0001. The results indicate that Inuit have liver zinc levels, which are similar to those found in Danes.

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. II. Iron measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of iron (Fe) in liver tissue samples from urbanized Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver tissue samples from urbanized Danes. Normal liver tissue samples were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 23-83) and from 72 Danes (42 men, 30 women) with a median age of 62 years (range 15-87). In the entire series, there was no significant difference between liver iron in Inuit compared with Danes. Likewise, there was no significant gender difference concerning liver iron content, either in Inuit or in Danes. The median iron content (with 5-95 percentile) in Inuit was 17.23 mmol/kg dry liver (5.80-91.80) and in Danes 16.51 mmol/kg dry liver (7.83-39.05). However, when stratified according to age, a trend was revealed showing that Inuit men and women < or = 50 years had a lower liver iron content than Danes (p = 0.05 and p = 0.08) whereas Inuit men and women > 50 years had a higher liver iron content than Danes (p = 0.18 and p = 0.02). There was a significant correlation between liver iron content and age in both Inuit men (rs = 0.49, p = 0.01) and in women (rs = 0.64, p = 0.003), but not in Danes. In Inuit, the median hepatic iron index (liver iron content divided by age) was 0.33 in men and 0.32 in women. The median estimated iron content in the whole liver was 6.54 mmol (365 mg) in Inuit men and 5.41 mmol (302 mg) in Inuit women (p = 0.6). There was no correlation between hepatic iron index and age. In Danes, the median hepatic iron index was 0.46 in men and 0.29 in women (p = 0.01). There was a significant inverse correlation between hepatic iron index and age in the two genders and in the entire series (rs = -0.71, p = 0.0001). The results indicate that young and middle-aged urbanized Inuit have slightly smaller iron stores than urbanized Danes, whereas elderly Inuit have higher iron stores than Danes. In Danes, iron stores plateau at 30 to 40 years of age in men and some years after the menopause in women. In Inuit, iron stores continue to increase in old age, probably to due a lifelong dietary intake of haem iron.

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. I. Sulphur, chlorine, potassium and bromine measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of the elements Sulphur (S), Chlorine (C1), Potassium (K) and Bromine (Br) in normal liver tissue samples from Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in normal liver tissue samples from Danes. Liver tissue sample were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 20-83) and from 74 Danes (44 men, 30 women) with a median age of 52 years (range 15-87). In Inuit, the content of elements given as median and (5-95 percentile) was: sulphur, 108.07 mmol/kg dry liver (86.78 - 169.44); chlorine, 92.16 mmol/kg dry liver (45.39-128.42); potassium, 181.66 mmol/kg dry liver (146.41-236.35); bromine, 0.0901 mmol/kg dry liver (0.0563-0.1589). In Danes, the corresponding values were: sulphur, 147.58 mmol/kg dry liver (70.41-236.81); chlorine, 96.95 mmol/kg dry liver (54.01-162.52); potassium, 198.40 mmol/kg dry liver (150.68-256.37); bromine, 0.1101 mmol/kg dry liver (0.0701 - 0.4203). None of the elements displayed any significant gender difference, neither in Inuit nor in Danes. Inuit had a lower liver content of sulphur (p < 0.0001), potassium (p < 0.008) and bromine (p < 0.002) as compared with Danes.