Warren Wilson

Why “Bitter” Cassava? Productivity of “Bitter” and “Sweet” Cassava in a Tukanoan Indian Settlement in the Northwest Amazon1

Cassava (Manihot esculenta Crantz) is a cyanide-containing root crop used by many indigenous groups in Amazonia. Despite the availability of low-cyanogenic potential (CNP) cassava, the Tukanoans of the Colombian Amazon region and many other indigenous groups in lowland Amazonia cultivate primarily high-CNP cassava as their staple crop. Based on the assumption that the Tukanoan preference for high-CNP cultivars is due, in part, to the ability of these cultivars to consistently produce higher yields, we tested the null hypothesis that low-CNP cassava has yields that are greater than or equal to the yields of high-CNP cultivars in Tukanoan gardens. To do so we compared the yields of low- and high-CNP cassava in 10 Tukanoan gardens and in one control garden. We reject the null hypothesis: high-CNP cultivars yielded more than low-CNP cultivars in both traditional Tukanoan Indian gardens and a control garden. Although there are several possible explanations for the differences in yields, the most plausible inference is that the high-CNP plants are more likely to be disease and/or insect resistant.ResumenLa yuca o mandioca (Manihot esculenta Crantz) es una raíz comestible que contiene cianuro, utilizada por numerosos grupos indígenas en la Amazonia. A pesar de que existe una variedad de yuca de bajo contenido en cianuro (CNP), los Tukanos de la región amazónica colombiana y muchos otros grupos indígenas en las tierras bajas del Amazonas cultivan principalmente la variedad de yuca con alto contenido en cianuro como alimento básico. Basándonos en la presunción de que la preferencia de los Tukanos por los cultivos de yuca de alto contenido en cianuro, se debe, en parte, a que esta variedad produce mayores rendimientos, intentamos comprobar la hipótesis de que la yuca de bajo contenido en cianuro logra rendimientos iguales o mayores que los de los cultivos de alto contenido en cianuro que realizan los Tukanos. Para ello, comparamos los rendimientos de la yuca de alto y de bajo contenido en cianuro en diez huertos de los Tukanos y en un huerto de control. Debemos descartar la hipótesis: los cultivos de alto contenido en cianuro rindieron más que los de bajo contenido, tanto en los huertos tradicionales de los indígenas como un el huerto de control. Aunque existen varias explicaciones posibles para esta diferencia en rendimiento, la más plausible es que las plantas con alto contenido de cianuro poseen mayor resistencia a los insectos y a las enfermedades.

Exploring the multidimensionality of stature variation in the past through comparisons of archaeological and living populations

Adult stature variation is commonly attributed to differential stress-levels during development. However, due to selective mortality and heterogeneous frailty, a populations tall stature may be more indicative of high selective pressures than of positive life conditions. This article examines stature in a biocultural context and draws parallels between bioarchaeological and living populations to explore the multidimensionality of stature variation in the past. This study investigates: 1) stature differences between archaeological populations exposed to low or high stress (inferred from skeletal indicators); 2) similarities in growth retardation patterns between archaeological and living groups; and 3) the apportionment of variance in growth outcomes at the regional level in archaeological and living populations. Anatomical stature estimates were examined in relation to skeletal stress indicators (cribra orbitalia, porotic hyperostosis, linear enamel hypoplasia) in two medieval bioarchaeological populations. Stature and biocultural information were gathered for comparative living samples from South America. Results indicate 1) significant (P < 0.01) differences in stature between groups exposed to different levels of skeletal stress; 2) greater prevalence of stunting among living groups, with similar patterns in socially stratified archaeological and modern groups; and 3) a degree of regional variance in growth outcomes consistent with that observed for highly selected traits. The relationship between early stress and growth is confounded by several factors-including catch-up growth, cultural buffering, and social inequality. The interpretations of early life conditions based on the relationship between stress and stature should be advanced with caution.

Amazonian foods and implications for human biology

Abstract Context: Diets of subsistence-based Amazonian populations have been linked to local resources, but are changing with market penetration. Objective: To review the available data on traditional Amazonian foods and diets and evaluate their implications for human biology as a step toward understanding nutrition transitions in the region. Methods: This study used the Human Relations Area Files for information on the diets of Amerindian groups in the Amazon Basin from 1950 to the present, and used other published sources and the authors’ own data. Results: Data on food use was identified for only nine groups and dietary intake data for individuals in only three of the groups. A diet based on starchy staples (manioc and plantains) and fish, supplemented with a limited variety of other plant and animal foods, was found. Bitter manioc-based foods were associated with the consumption of cyanogens and fish with the consumption of mercury. Diets of adults appear to be adequate in energy and protein and low in fats. Children’s diets were not well documented. Conclusion: Based on the limited available data, Amazonian diets are restricted in variety, but appear to be adequate in energy and protein for adults, but likely insufficiently nutrient-dense for children.

Nutritional status of Makushi Amerindian children and adolescents of Guyana

Background: Amazonian Indians are in the midst of a rapid cultural transition. The developments affecting Amazonian Indians present an opportunity to address important public health problems through public and private initiatives, but to do so it is imperative to begin with information on the health status of these peoples and the underlying factors affecting it. However, relatively few such data are available for this vast region. Aim: This study describes the nutritional status of Makushi Amerindians of Guyana and considers several variables which might help to explain it. Subjects and methods: Data for 792 Makushi, 0–20 years of age from 11 villages are considered. Outcome variables considered are anthropometric markers of growth and nutritional status; specifically height-for-age, weight-for-height and body-mass index. Predictor variables explored are age, sex, relative isolation, number of siblings, season of birth, diet and morbidity. Fishers exact test, chi-square, Pearsons correlation and multiple regression were used to assess possible relationships between these variables. Results: Relative to other Amazonian Indians, the Makushi have a lower rate of linear-growth faltering and a higher rate of linear-growth faltering relative to non-Amerindian Guyanese. Males, older cohorts, those living in isolated villages or born in the wet season showed higher rates of growth faltering. Conclusion: Makushi nutritional status may be explained by sex, age, relative isolation, family size, season of birth, dietary intake and infectious disease.

The Use of Remotely Sensed Data in Rapid Rural Assessment

This article discusses how analysis of remotely sensed data can be applied in rapid rural assessment and how its application can expand the spatial analysis of land-use/land-cover (LULC) change. It describes the methodological steps to carry out an LULC analysis based on Landsat Thematic Mapper image analysis under time and budget constraints. The article presents intra-and intercommunity comparisons of different LULC patterns. The discussion focuses on the trade-off between the desirable degree of land-cover class complexity, the level of class detail, and the required ground-truthing associated with each of these choices. The authors conclude that remotely sensed analysis can enhance short-term, low-budget fieldwork. Analysis of remotely sensed data can reduce costs before fieldwork by helping to inform where to concentrate data collection efforts, during fieldwork by extending spatial analysis to areas where accessibility is poor and that otherwise would not be included, and after fieldwork by improving the spatial and temporal scope of the analysis.

Household-level predictors of maternal mental health and systemic inflammation among infants in Mwanza, Tanzania.

Household conditions and culturally/socially variable childcare practices influence priming of the inflammatory response during infancy. Maternal mental health may partially mediate that effect. Among mother–infant dyads in Mwanza, Tanzania, we hypothesized that poorer maternal mental health would be associated with adverse household ecology, lower social capital, and greater inflammation among infants under the age of one; and that mental health would mediate any effects of household ecology/social capital on inflammation.

Comparison of Infant Vitamin D Supplement Use Among Canadian-Born, Immigrant, and Refugee Mothers

Purpose:This study compares knowledge and practice of infant vitamin D supplementation among immigrant, refugee, and Canadian-born mothers. Method: Focus group discussions with 94 mothers of children aged 0 to 3 years recruited from early childhood centers and a refugee health clinic. Findings: Both immigrant and Canadian-born mothers indicated good knowledge and use of infant vitamin D supplementation. In contrast, Canadian government-assisted refugees were less likely to supplement with vitamin D. The main source of information about vitamin D was public health prenatal classes. Many mothers reported inconsistent guidance from health care providers. Discussion and Conclusions: Exclusively breastfed infants of refugees may be more at risk of vitamin D deficiency. All mothers require clear recommendations, both in clinical and public health settings. Implications for Practice: Mothers, both new Canadian and Canadian-born, require clear and consistent messaging from health professionals. Refugee mothers, however, require more educational support to promote infant vitamin D supplementation.

Facial shape manifestations of growth faltering in Tanzanian children

Variation in the shape of the human face and in stature is determined by complex interactions between genetic and environmental influences. One such environmental influence is malnourishment, which can result in growth faltering, usually diagnosed by means of comparing an individuals stature with a set of age‐appropriate standards. These standards for stature, however, are typically ascertained in groups where people are at low risk for growth faltering. Moreover, genetic differences among populations with respect to stature are well established, further complicating the generalizability of stature‐based diagnostic tools. In a large sample of children aged 5–19 years, we obtained high‐resolution genomic data, anthropometric measures and 3D facial images from individuals within and around the city of Mwanza, Tanzania. With genome‐wide complex trait analysis, we partitioned genetic and environmental variance for growth outcomes and facial shape. We found that children with growth faltering have faces that look like those of older and taller children, in a direction opposite to the expected allometric trajectory, and in ways predicted by the environmental portion of covariance at the community and individual levels. The environmental variance for facial shape varied subtly but significantly among communities, whereas genetic differences were minimal. These results reveal that facial shape preserves information about exposure to undernourishment, with important implications for refining assessments of nutritional status in children and the developmental‐genetics of craniofacial variation alike.