Nutritional Assessment in a Rural Area of Bolivia. A Study of Zinc and Iron Deficiencies and Bioavailability

Abstract

While originally, protein-energy deficiency was considered the main factor of malnutrition, it is now understood that micronutrient deficiencies play a fundamental role in a variety of health and disease outcomes. Zinc and iron deficiencies are still highly prevalent in low-income countries, whereas insufficient intakes and diets with low mineral absorption are the major causes. Sustainable and feasible dietary strategies are needed to alleviate micronutrient deficiencies.

The present research was designed to evaluate the nutritional status of adults and children from a rural tropical area in Bolivia. The evaluation was made taking into account: nutrient intakes assessed by our new developed and validated dietary assessment method, anthropometric measurements and biochemical indicators of trace element status. With a focus on elucidating the causes of existing deficiencies of zinc and iron, the content of the mineral absorption inhibitor phytate was evaluated in the main foods and in the dietary intake of the studied populations; the presence of parasitic diseases and their effect on the trace element status was also evaluated. Furthermore, the inclusion of a fermented food in the basal tropical diet was carried out in order to improve the absorption of zinc in the diet, it was evaluated in Wistar rats and compared with zinc-supplemented diets.

The developed method for dietary assessment is based on digital photographs and it was satisfactorily validated against a reference method. Results of the dietary intake of children and adults showed the dietary patterns, mainly based on plant-foods: the main source of energy was carbohydrates 63-71%E from starchy tubers, cereals, and legumes, fat 16-23%E from oil or tallow, and protein 13-14%E from plant-foods and a small contribution of animal-food sources. In adults, 7% (women) were underweight. Zinc deficiency was found in 15% of controls and 29% of patients with leishmaniasis. The nutritional status of children was more diminished, indicating 37% as being stunted, 17% wasted and 17% underweight, 87% zinc deficient and 66% iron deficient. The zinc deficiencies were negatively associated to the high levels of phytate in the diet, indicated by the correlations between serum zinc and phytate:zinc molar ratios; for adults -0.410 and children -0.458 (P<0.01). Parasitic infections; leishmaniasis and intestinal parasites have also been shown to have a negative effect on zinc and iron status. Finally, the inclusion of fermented cassava, in the basal plant-based diet was shown to have a positive effect increasing the zinc apparent absorption of the diet from 16.5 to 40.2%, which is comparable to results obtained when the diet was supplemented with zinc.

In conclusion, this research presents a suitable and reliable method for assessing the dietary intake in rural populations in developing countries. The dietary patterns of a rural population from Bolivia are presented, shedding light on the existence of zinc and iron deficiencies indicated to be caused by high levels of phytates in their diet and by the presence of parasitic diseases. Additionally, fermentation is presented as an efficient dietary strategy for the improvement of zinc absorption in the plant-based diet of the studied population; it may represent a better nutritional and economical alternative than the use of supplements, adequate for rural areas in developing countries, where the diets are limited in animal-food sources.

Abstract (Swedish)

Popular Abstract in English

Malnutrition and micronutrient deficiencies continue to be a major health problem, especially in rural areas in developing countries. It is of great importance to have reliable data about the existing deficiencies, and also about their main causes, for the designing and developing of efficient nutritional strategies in order to overcome nutritional problems. Bolivia is a developing country, where still to date, there is a lack of data on the nutritional status of rural and urban populations.

Consequently, the aim of the present research was: Firstly, to provide reliable data about the actual nutritional status, focused on zinc and iron deficiencies, in a population of children and adults from a rural tropical area called Chapare in Bolivia. Secondly, to determine the possible causes of the deficiencies, and thirdly, to present a sustainable dietary strategy other than the use of mineral supplements, to improve the mineral absorption in the diet commonly consumed in the area.

The results showed the dietary patterns among adults and children, which are mainly based on plant-foods such as starchy tubers, cereals, and legumes. Plant-based diets are usually associated with micronutrient deficits. In the studied population, there was a certain percentage of zinc deficiency in adults; in children the situation of zinc deficiency was more worrisome; besides, it was accompanied by iron deficiency and a high percentage of stunted children.

It was determined that mineral deficiencies were due to the small amounts of animal-foods. In these diets, the plant-foods are the main contributors, not only of energy and protein but also of minerals. However, plant-foods have the disadvantage of containing high levels of mineral absorption inhibitors like phytate, which form insoluble substances with the divalent minerals making them non-utilizable by the body functions. Apart from mineral inhibitors in the diet, other factors that can aggravate the existing mineral deficiencies, such as the presence of parasitic diseases, were found.

Furthermore, in order to reduce the phytate content in the studied diet and increase the mineral absorption, fermentation was presented as a dietary strategy. The inclusion of a fermented food in the basal plant-based diet showed an improvement in zinc absorption comparable to that obtained by the use of zinc supplements.

In conclusion here, we present evidence of existing micronutrient deficiencies in the rural area Chapare-Bolivia. The most likely causes are the plant-based diets with high levels of phytates and the presence of parasitic diseases. Furthermore, fermentation is presented as a promising dietary strategy, advantageous, in practical and economical terms, for the improvement of mineral absorption, in order to decrease mineral deficiencies highly prevalent in developing countries where animal-food sources are limited.



Popular Abstract in Spanish

La desnutrición y las deficiencias de micronutrientes continúan siendo un gran problema relacionado a la salud, especialmente en las zonas rurales de los países en desarrollo. Es de gran importancia contar con datos fiables sobre las deficiencias existentes, así como también determinar las principales causas de las deficiencias, estos datos son necesarios para diseñar y desarrollar estrategias nutricionales eficaces. Bolivia es un país en desarrollo, donde no se cuentan con datos actuales sobre el estado nutricional de las poblaciones rurales y urbanas.

Por lo tanto, los objetivos de la presente investigación fueron: en primer lugar, proporcionar datos fiables sobre el estado nutricional actual de una población de niños y adultos de una zona tropical rural llamada Chapare en Bolivia, con énfasis en las deficiencias de zinc y hierro. En segundo lugar, determinar las posibles causas de las deficiencias, y en tercer lugar, presentar una estrategia dietética sostenible que no sea el uso de suplementos de minerales, para mejorar la absorción de minerales en la dieta de consumo habitual en la zona.

Los resultados mostraron que los patrones alimentarios de los adultos y los niños, se basan principalmente en una dieta de origen vegetal: tubérculos, cereales y legumbres. La población de adultos estudiada, presentó bajo porcentaje de deficiencia de zinc, sin embargo en los niños se encontraron elevados porcentajes de deficiencia de zinc y hierro, además de un alto porcentaje de niños con retraso de crecimiento.

Se determinó que las deficiencias de minerales se deben a que la dieta de estas poblaciones se basa en alimentos de origen vegetal, los cuales son los principales contribuyentes, no sólo de energía y proteína, sino también de los minerales. Sin embargo, los alimentos de origen vegetal tienen la desventaja de contener altos niveles de inhibidores de absorción de minerales como ser fitatos, los cuales que forman sustancias insolubles con los minerales divalentes evitando que sean utilizados por las funciones del organismo. Además de los inhibidores de minerales en la dieta, se determinó que las enfermedades parasitarias pueden agravar las deficiencias de minerales.

Adicionalmente, con el fin de reducir el contenido de fitatos en la dieta estudiada y aumentar la absorción de minerales, la fermentación se presenta como una estrategia dietética. La inclusión de un alimento fermentado en la dieta básica de origen vegetal, mostró una mejora en la absorción de zinc comparable a la obtenida por el uso de suplementos de zinc.

En conclusión el presente trabajo de investigación presenta resultados de las deficiencias de zinc y hierro existentes en el área rural del Chapare - Bolivia. Así como también presenta los factores causantes de las deficiencias, los cuales resultaron ser: los niveles elevados de ingesta de fitatos en la dieta y la presencia de enfermedades parasitarias. Por otra parte, la fermentación se presenta como una estrategia prometedora, en términos prácticos y económicos, para la mejora de la absorción de minerales, con el fin de disminuir las deficiencias de minerales altamente prevalentes en áreas rurales de los países en desarrollo, donde las fuentes de alimentos de origen animal son limitadas.

• author: Lazarte, Claudia
• supervisor: Yvonne Granfeldt
• opponent: Dr. Ferguson, Elaine, Nutrition and Public Health Intervention Research Unit, London School of Hygiene and Tropical Medicine, London, United Kingdom
• organization: Department of Food Technology, Engineering and Nutrition
• publishing date: 2014
• type: Thesis
• publication status: published
• subject: Food Engineering
• keywords: zinc, iron, deficiencies, bioavailability, fermentation, developing countries, plant-based diets
• pages: 130 pages
• defense location: Lecture Hall B, Center of Chemistry and Chemical Engineering, Getingevägen 60, Lund University Faculty of Engineering
• defense date: 2014-01-10 10:15:00
• ISBN: 978-91-7473-768-4
• project: CAP
• language: English
• LU publication?: yes
• id: 6830c399-3a22-4847-97cd-249d6928cbe3 (old id 4195825)
• date added to LUP: 2016-04-04 10:00:06
• date last changed: 2024-01-30 10:28:40