Improving Nutrition through Biofortification

Publiceret Januar 2009

Billions of people worldwide suffer from micronutrient malnutrition, also known as hidden hunger. The consequences, in terms of malnutrition and health, are devastating and can result in blindness, stunting, disease, and even death. Hidden hunger is caused by a lack of micronutrients in the diet. Among the critical micronutrients identified by the WHO as most lacking in the diets of the poor are zinc, iron, and vitamin A. Only minute amounts of these nutrients are required for good health, and even survival. A diverse diet that includes fruits, vegetables, and animal products can provide all the required micronutrients.

However, the diets of the poor in developing countries, who live mostly in rural areas, consist largely of inexpensive staple foods, such as rice or maize that provide insufficient nutrition.  Furthermore, rising food prices have meant that the poor are less able to afford more nutritious foods that could provide them with needed micronutrients.

Biofortification – A New Approach

Breeding crops to be naturally higher in nutrients through a process called biofortification, is a promising new strategy to reduce hidden hunger that has several advantages. First, as a food-based intervention, biofortification uses the very staple foods that the poor are already eating to deliver necessary micronutrients to them. Therefore, biofortified foods are more easily integrated into the livelihoods and diets of the poor.   Second, it is an agricultural intervention targeted to rural areas where more than seventy-five percent of the poor in developing countries live, and where access to supplements, fortified foods and other urban-based interventions are limited. Third, a one-time investment in breeding biofortified crops would provide micronutrients far more cost-effectively than through conventional means, which have high annual recurring costs (table 1). The 2008 Copenhagen Consensus recognized this, listing biofortification as one of its top five solutions to global challenges.  Furthermore, once developed, biofortified crops can be adapted to similar agroecological zones, or improved, at relatively low additional cost.

Supplementation

Fortification

Biofortification

Vitamin A supplementation for ONE year only to 37.5 million pre-school children in Bangladesh, India, and Pakistan

Iron fortification for one year for 375 million persons, about 30% of the population in Bangladesh, India, and Pakistan.

Estimated cost of developing and disseminating iron and zinc dense rice and wheat varieties for South Asia, which would be available year after year.

Table 1. How much nutrition a US$75 million investment can buy?

In short, biofortification may well prove to be a sustainable long-term approach for providing millions of poor people in developing countries with at least a part of their micronutrient requirements. As a component of a strategy that includes dietary diversification, supplementation and commercial fortification significant progress could be made in reducing hidden hunger globally.

The Role of HarvestPlus

Since 2004, HarvestPlus, a Challenge Program of the Consultative Group on International Agricultural Research, has led the charge to breed and disseminate micronutrient-rich biofortified crops. HarvestPlus is an inter-disciplinary program of plant breeders, molecular biologists, nutritionists, economists, and communication and behavior change experts. It focuses on three critical micronutrients lacking in the diets of the poor: vitamin A, zinc and iron.  Through a global alliance now involving more than two hundred scientists, HarvestPlus is biofortifying seven staple food crops that are critical in the diets of the poor in developing countries. Table 2 shows these crops, the nutrient they will deliver, and the countries of first-release where these crops are expected to be field-tested and then released. There are more than twenty ‘spillover’ countries, which would also benefit from these biofortified varieties following their initial release in selected target countries.

Crop

Nutrient

Countries of first release

Sweet Potato

Provitamin A

Uganda, Mozambique

Bean

Iron

Rwanda, D.R. Congo

Pearl Millet

Iron

India

Cassava

Provitamin A

Nigeria, D.R. Congo

Maize

Provitamin A

Zambia

Rice

Zinc

Bangladesh, India

Wheat

Zinc

India, Pakistan

Table 2: HarvestPlus Target Crops, Nutrients and Countries

Will Biofortification Work?

For biofortification to work, several questions need to be answered:

  1. Can breeding increase the micronutrient content in food crops to target levels that will have a measurable impact on nutritional status?
  2. Will the extra nutrients bred into the staple food be bioavailable and absorbed at sufficient levels to improve micronutrient status?
  3. Will farmers adopt the biofortified varieties and will consumers eat them in sufficient quantities to improve their nutrition?

In its first four years (2004-2007) HarvestPlus has identified sufficiently high nutrient-rich germplasm to use in its biofortification breeding program as shown in the chart below.

Scientists are now working to breed high-nutrient traits into agronomically superior varieties. Many of these new varieties are already undergoing rigorous field tests in target regions where malnourished people live. Nutrition scientists are also working closely with plant breeders to determine just how much of a nutrient must you breed into a crop to improve human nutrition. This depends on how much of the staple food is typically eaten by malnourished populations, and the assumed bioavailability of nutrients. Nutrients are also lost following harvest during storage, processing, or cooking. Scientists must account for all losses from cultivation through consumption in determining breeding target levels.

Nutritional genomic scientists are also trying to identify and understand genes related to the increase of iron and zinc and the synthesis of provitamin A carotenoids. Processes that can be used to influence mineral transport in crops, increase bioavailability of nutrients and influence both the stability and conversion of provitamin A carotenoids into retinol are also being investigated. Initial research into whether biofortified food can improve micronutrient status has been promising. For example, in Mozambique, where the prevalence of vitamin A deficiency among children of ages six months to five years is estimated at more than 70%, resulting in a high risk of permanent blindness, researchers found that orange-fleshed sweetpotato, which has higher levels of Vitamin A compared to lighter colored varieties, increased vitamin A intake and levels in young children (Low et al.).

However, breeding nutrient-rich crops will be of little use if farmers do not grow them. Biofortified crop varieties must perform as well, or better, than popular varieties. For example, scientists have bred new varieties of bean that not only have higher levels of iron but are more heat and drought tolerant. HarvestPlus works closely with national agricultural research systems and non-governmental organizations to deploy biofortified varieties in target countries once approved varieties are ready to be disseminated.

The last, yet crucial, question is whether consumers will eat biofortified foods. The most significant obstacle is when there is a visible or detectable change to the food as a in the case of high provitamin A foods, that tend to be orange in color. For example, in Africa, people prefer to eat traditional white sweet potato while the new high provitamin A varieties are orange in color. Convincing consumers to switch to these new varieties is not easy, but as early studies have shown, they are willing to make the switch when the nutrition and economic benefits of growing and eating orange sweet potato are made apparent.  Other nutrients, like zinc and iron can be added without any visible or detectable differences, and should be easier to introduce.

Micronutrient levels in different staple crops
Figure 1: Micronutrient levels in different staple crops

Conclusion

The challenge of hidden hunger requires that agriculture and nutrition disciplines work more closely together to improve human nutrition.  This requires building a multidisciplinary research team of scientists from different disciplines. An important component of this is encouraging plant breeders in developing countries to include micronutrients in their breeding portfolios along with higher yield, disease resistance and other agronomic traits.  Similarly, nutritionists and public health official must begin to understand the complexities of food as a tool to improve micronutrient malnutrition.  It will be far easier to build support for this new strategy among research scientists, health professionals, and policymakers, once biofortification is proven a viable, cost-efficient and effective solution for combating micronutrient malnutrition. HarvestPlus believes that this will be evident by 2012 when the first varieties of biofortified crops are released in target developing countries.

References

Jan w. Low, Mary Arimond, Nadia Osman, Benedito Cunguara, Filipe Zano, and David Tschirley. A Food-Based Approach Introducing Orange-Fleshed Sweet Potatoes Increased Vitamin A Intake and Serum Retinol Concentrations in Young Children in Mozambique. 2007. The Journal of Nutrition 137(5): 1320