Nutrition Transition and Total Nail Selenium in the Peruvian Amazon in the IMAS Study (Investigation De Migracion, Ambiente, Y Salud)

摘要

Road development has been a major driver of the transition from traditional to calorie-dense processed 'Western' diets in lower and middle income countries. The paving of the Interoceanic Highway (IOH) brought rapid development to the Madre de Dios (MDD) region in the Peruvian Amazon. As traditional foods such as Brazil nuts and fish are high in selenium, we hypothesized that nail selenium may be an appropriate biomarker to measure the nutrition transition. To test this hypothesis, in 2014 we collected household surveys from 310 households in 46 communities along the IOH and nails from 418 adults. Principal component analysis of consumption frequency of 26 food items identified a Western diet factor, and we calculated household Western diet weighted sum factor scores. Diet score means were mapped into a 10 km buffer around the IOH. Generalized estimating equations (GEE) assessed the effect of this score on individual nail selenium. GEE's also assessed the influence of each food on nail selenium in urban and rural localities. Sharp differences in nail selenium were observed between urban and rural communities in an area dominated by subsistence agriculture, and higher rates of dietary transition in areas dominated by small scale artisanal gold mining and population influxes. Urban/rural status modified the effect of Western diet on nail selenium: we estimate the total nail selenium of an urban, 47 year-old (mean-aged) non-smoker would decrease 23 ng/g per unit increase in Western diet score, while rural counterparts would experience a 6 ng/g increase in selenium. Chicken, a non-traditional food, was positively associated with selenium in the rural stratum only. It is possible that chickens consumed in rural areas are raised in the household and exposed to selenium-rich local soils and food scraps. We conclude that total nail selenium is not an appropriate biomarker for stage of dietary transition in the primarily rural settlements in MDD.