Efficacy of quality protein maize-based supplementary foods on rehabilitating undernourished Children in Mvomero District, Tanzania

Abstract

Child undernutrition is a persistent problem in Africa, especially in areas where the poor largely depend on starchy staples with limited access to diverse diets. Despite the fact that Tanzania has given attention to undernutrition, the prevalence rate is still high. Inappropriate feeding practices may account for approximately one-third of undernutrition. Traditional supplementary feeding of infants and young children in Tanzania and much of Africa is commonly based on maize porridge, usually made from plain maize. Low energy density of maize-porridge, linked with its low quality protein, low micronutrients and low lysine and tryptophan, make maize porridge a poor supplementary food for infants and young children. One intervention in mitigating these limitations was biofortification of maize initiated by International Maize and Wheat Improvement Center. The intervention involved developing maize cultivars with protein high in lysine and tryptophan, known as quality protein maize. Despite the fact that utilization of quality protein maize as part of a family diet is growing steadily in Tanzania, there is little information on the use of quality protein maize in supplementary feeding. The current study therefore, was designed to fill this gap by evaluating the efficacy of quality protein maize-based composite supplementary foods on rehabilitation of undernourishedchildren in Mvomero District. Three composite diets were prepared from quality protein maize, namely quality protein maize-soybeans; quality protein maize-soybeans-common beans and quality protein maize-soybeans- cowpeas. Two control diets were prepared from plain quality protein maize and common maize. These diets were extruded atan average temperature of 125oC with retention time of 2 minutes. The formulations were made to meet the greatest amino acid score and the desired amount of energy and fat according to the FAO/WHO (1985) recommendation for pre-school children. The third control diet (Chesta®) used for rat was made from maize, soybeans, fish, bone and blood meal. Albino rats were used in evaluating the protein iii quality of the formulations, whereas 150 children (2-5 years) were used to evaluate the rehabilitation potential of the formulations from undernutrition. Results showed that, protein digestibility-corrected amino acid scores were 80% (quality protein maize-soybeans-common beans), 80% (quality protein maize-soybeans-cowpeas), 87% (quality protein maize-soybeans), 100% (common maize alone) and 98% (quality protein maize). Baseline study of the undernourished children showed that pre-lacteal feeding was common in the study area (40%). Children were introduced to complementary foods too early (˂6 months) and plain maize porridge was the first food to be introduced. Mostchildren (57.2%, n=86) were on the lowest tercile (≤3 food groups per day) of dietary diversity score. Furthermore, logistic regression analysis revealed that, family’s source of income and breastfeeding frequency were among the factors that influenced stunting of children significantly. Other factors such as age of the child, age at introduction of complementary food, dietary diversity score ≤3 food groups, consumption of animal foods, family size and use of non- potable water were also risk factors that predicted child stunting. A randomized longitudinal study with intention to rehabilitate the undernourished children showed that, quality protein maize-based diets had positive effects (p<0.05) on weight, height, weight-for-age, height-for-age, weight-for-height Z-scores and haemoglobin concentrations but not on mid-upper arm circumference. Children consuming conventional maize porridge progressively faltered in growth with weight-for age decreasing from -1.9 to -2.1 SD, height-for age from -2.0 to -2.9 SD, weight for height from -1.2 to -1.9 SD and haemoglobin levels decreasing from 10 to 9.9 (g/dL). During the 16 weeks of rehabilitation, 68% (n=27) of children receiving quality protein maize-soybeans-common beans diet grew back to normal weight for age Z-score of ≤ -2SD. For children receiving quality protein maize-soybeans-common beans diet, 50% (n=23) of the undernourished children grew back to normal weight for age and only 19.5% (n=9) of the children receiving conventional porridge diet grew back to normal iv weight for age Z-score. Quality protein maize-soybeans-common beans diet had higher potential to support growth than the other diets. The growth velocities for children in various groups were 0.39 g/month for quality protein maize-soybeans-common beans, 0.28 g/month for quality protein maize-soybeans-cowpeas and 0.13 g/month for conventional maize diets. Quality protein maize-soybeans-common beans and quality protein maize-soybeans-cowpeas met RDA for both energy (360 kcal) and protein (16 g) for children 2-5 years. Amino acid scores for quality protein maize-based diets were higher than the recommended amino acid scores (≥65%) for optimal growth of children. Concentrations of fumonisin B1 and total fumonisin were 1687.82 and 1717.16 μg/kg in plain quality protein maize and 1625.08 and 1745.22 μg/kg in plain common maize, respectively. These values were all above the maximum tolerable limit of 1000 μg/kg recommended by the European Commission. Consumer evaluation revealed that, quality protein maize-soybeans-common beans porridge was rated higher (p˂0.05) for aroma and taste than quality protein maize-soybeans-cowpeas and conventional porridge. All the porridges (quality protein maize-soybeans-common beans; quality protein maize-soybeans-cowpeas and conventional porridge), were however equally acceptable (p˃0.05) by the test panel. Experimental porridge was distinguished in principal component 1 by the sensory attributes of colour, oiliness, aroma, sweetness, liking and aftertaste from the control. However, all the porridges could be described by viscosity, sweetness and colour in principal component 2. Two diets quality protein maize-soybeans-common beans and quality protein maize-soybeans-cowpeas showed the greatest potential for rehabilitation of undernourished children. Public awareness on the use of quality protein maize as an ingredient in making complementary food is therefore recommended