Demographic and socioeconomic determinants of variation in food and nutrient intake in an Andean community

Understanding the sources of variation in a community's diet is vital for development work, as well as being a source of anthropological and cultural insights. Previous surveys in the South American Andes suggest that nutrient deficiencies may be widespread; however, such interpretations have remained tentative since variance in Andean populations' diet has not been thoroughly examined. In this paper we consider the variation in diet due to variation in age, sex, and socioeconomic status and variation attributed to inter- and intraindividual variation in the diet. One to six days of dietary data (mean = 3.1) were collected via 24 h recalls from 221 residents of a small, rural community in highland Ecuador. The contribution of various food groups to the diet varied with land holdings and age but not sex. For example, animal-derived foods contribute more and tubers contribute less to the diet of the households with > or = 5 Ha, and sweets contribute more to the diet of children. The interindividual variation in energy and nutrient intake was low and the intraindividual variation high relative to developed countries. The consequence are twofold. First, because interindividual variability is low, group mean intake can be estimated relatively easily, facilitating group comparisons. Second, because intraindividual variation is high, individual nutrient intake cannot be easily estimated, which will decrease the ability to detect associations between nutrient intake and health measures. This knowledge of the sources of dietary variation can lead to better study and survey designs in the rural Andes and elsewhere in the developing world.

Population exposure to radioactivity from consumption of caribou among the Dene/Métis of Denendeh (western Northwest Territories, Canada)

There has been long-standing concern with exposure to radioactivity through the consumption of caribou, particularly in indigenous populations in the western Northwest Territories, Canada, who are traditionally high consumers. We conducted a dietary survey in this region in 1994 to estimate population exposure levels. Dietary information was collected from 1012 individuals in sixteen communities (1012 days of 24-hour dietary recalls, 1012 food frequency questionnaires) and radionuclide levels in caribou flesh, liver and kidneys were measured. Monte Carlo statistical methods were employed to integrate these data sets and estimate the distribution of radiation exposure for people in five regions (Gwich'in, Sahtú, Dogrib, Deh-Cho, South Slave). The exposure levels were highest in the South Slave region and in older males (40+ years), and lowest in the Gwich'in region and in younger females (20-40 years). Median exposure level ranged from 0.95 to 5.31 mSv per year (mean of medians = 2.96 mSv/y). In each group the 95th percentile of exposure was 2-3 times greater than the median. These exposure levels are comparable to exposure levels in Alaskan Eskimos and Marshall Island residents, and are much higher than European or American urban populations. Caribou meat is a very nutritious food. We conclude that, although there is some radiation exposure from consuming caribou, the associated health risks are low and are outweighed by the physical, social and cultural benefits derived from hunting and eating caribou.

Dietary exposure to chemical contaminants from traditional food among adult Dene/Métis in the western Northwest Territories, Canada

Environmental contaminants such as organochlorines and heavy metals have been reported to bioaccumulate in Arctic and subarctic wildlife. The Indigenous Peoples in northern and Arctic Canada rely on local wildlife as an important food source, and it is thus hypothesized that they may have high intakes of these contaminants. Herein, an assessment of dietary exposure to selected organochlorines and heavy metals for Indigenous Peoples of the western Northwest Territories (NWT) is presented. Dietary data were collected from 1012 adults with 24-h recalls in 16 communities in the western NWT (Denendeh). A comprehensive survey of the literature, as well as in-house analysis, formed the basis of a large traditional food-contaminant database. By combining the dietary and contaminant data, dietary exposure to 11 chemical contaminants was calculated. Dietary exposure to chemical contaminants in Denendeh is generally low and there is little, if any, associated health risk. However there are specific contaminants in certain communities for which exposure on a single day approaches the tolerable daily intake levels. These situations are detailed and monitoring needs are described.

Evaluation of the population distribution of dietary contaminant exposure in an Arctic population using Monte Carlo statistics

Organochlorines and heavy metals have bioaccumulated in Arctic wildlife, which is an important food source for the Inuit. In this study, we have developed a statistical model to describe the population distribution of contaminant exposure and the usual intake of the high-end contaminant consumers. Monte Carlo methods are used to account for variations due to seasonal dietary pattern and contaminant concentrations. Distribution of the dietary intake of the contaminants of most concern-mercury, polychlorinated biphenyls (PCBs), chlordane, and toxaphenes-are described. Over 50% of the residents had dietary exposure levels exceeding the tolerable daily intake or provisional tolerable daily intake for Hg, toxaphene, and chlordane (83, 91, and 71% for men and 73, 85, and 56% for women, respectively). The high-end consumers (i.e. the 95th centile) have intake levels 6 times higher than the provisional tolerable weekly intake of Hg, and over 20 times the tolerable daily intake of chlordane and toxaphene. Assessment of health risks of the relative high contaminant exposure in this community must also consider the nutritional, economical, cultural, and social importance of these traditional foods. A comprehensive risk management scheme has yet to be developed.

Differences between observed and predicted energy costs at rest and during exercise in three subsistence-level populations

Estimates of daily energy expenditure are important for many areas of research in human ecology and adaptability. The most common technique for estimating human energy expenditure under field conditions, the factorial method, generally relies on activity-specific energy costs derived from published sources, based largely on North American and European subjects. There is concern that such data may not be appropriate for non-Western populations because of differences in metabolic costs. The present study addresses this concern by comparing measured vs. predicted energy costs at rest and during sub-maximal exercise in 83 subjects (52 males, 31 females) from three subsistence-level populations (Siberian herders and highland and coastal Ecuadorian farmers). Energy costs at rest (i.e., lying, sitting and standing) and while performing a standard stepping exercise did not significantly differ among the three groups. However, resting energy costs were significantly elevated over predicted levels (+ 16% in men, + 11% in women), whereas exercising costs were comparable to predicted values (-6% in men, + 3% in women). Elevations in resting energy needs appear to reflect responses to thermal stress. These results indicate that temperature adjustments of resting energy costs are critical for accurately predicting daily energy needs among traditionally living populations.