Evaluating the nutritional impact of maize varieties genetically improved for protein quality

Nilupa S Gunaratna, Purdue University

Abstract

Biofortification, or the genetic improvement of the nutritional quality of food crops, is a promising technology to combat childhood undernutrition in developing countries. Significant progress has been made to develop maize varieties with improved protein quality, collectively known as quality protein maize (QPM). However, debate still continues over whether this agricultural technology will have a significant public health impact. A four-level framework was proposed to evaluate the nutritional impact of QPM and biofortified crops. Using the results of community-level efficacy and effectiveness studies on QPM that have been conducted in several countries in Sub-Saharan Africa, Latin America, and Asia, a meta-analysis was performed to assess the effect of QPM on child growth. The results indicated that consumption of QPM compared with conventional maize varieties leads to an 8% (95% CI: 4-12%) increase in the rate of growth in height and a 9% (95% CI: 4-12%) increase in the rate of growth in weight in infants and toddlers with mild to moderate undernutrition for whom maize is a significant part of the diet. These results were not sensitive to alternative methods of determining the summary effect size and its statistical significance. However, the studies used to derive these estimates had several methodological limitations, and further community-level nutritional studies were recommended to provide stronger evidence on the efficacy and effectiveness of QPM. Simulation was used to study the potential impact of QPM on nutrient adequacy at the population level. Methods were developed to incorporate potential impact pathways for biofortified crops, allowing quantitative discrimination of scenarios of high and low impact. These methods were then used to examine factors that could modify the impact of a new crop. Simulation results indicate that impact depends on adoption and production patterns, composition of the total diet, variation in food consumption patterns, self-sufficiency in and sources of maize, disease, and other factors, as well as seasonal effects on the above. In particular, they highlight the importance of monitoring total diet and morbidity in targeting and impact assessment. These factors should be considered in the planning and implementation of biofortification programs.

Degree

Ph.D.

Advisors

McCabe, Purdue University.

Subject Area

Statistics|Nutrition

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