A study on vitamin A-enriched orange sweet potato that was released in Uganda in the mid 2000s not only gave evidence that the new varieties were accepted by the Ugandans, but also showed that vitamin A intake has measurably increased, particularly among the most vulnerable groups, like small children and women.

Vitamin A deficiency is a major public health concern in poorer countries and accounts for more than 600,000 deaths a year among children under five years of age. In Africa, Vitamin A deficiency prevalence is estimated at 42 per cent among children under five. The deficiency can impair immunity and cause eye damage that can lead to blindness and even death.

Sweet potato with new properties

In many African countries, white or yellow sweet potato varieties are an important staple crop, but these provide little, or no, vitamin A. An orange-coloured variety which not only contains high vitamin A levels but is also high-yielding and drought-tolerant was developed by HarvestPlus via conventional breeding. HarvestPlus is part of the Research Program on Agriculture for Nutrition and Health of the Consultative Group on International Agricultural Research (CGIAR).

Between 2007–2009, HarvestPlus and its partners disseminated new Orange Sweet Potato (OSP) varieties to more than 10,000 farming households in Uganda. The project provided OSP vines for farmers to grow, as well as extension services and nutritional information so that farmers could incorporate OSP into their cropping systems. Since sweet potato is available for about ten months a year, it can be a rich and steady source of vitamin A.

The project in Uganda resulted in 61 per cent of households adopting the vitamin A-rich OSP to grow on their farms. According to the study, the farm families were also willing to substitute more than one-third of their traditional white and yellow sweet potato consumption with OSP. This level of substitution was enough to push large numbers of children and women over the threshold, ensuring that their daily requirements for vitamin A were met.

Promising results

The study revealed that vitamin A intake increased by two-thirds for older children and nearly doubled for younger children and women by project end. For children of six to 35 months, who are especially vulnerable, OSP contributed more than 50 per cent of their total vitamin A intake. The high prevalence of inadequate vitamin A intake among a subset of children of 12 to 35 months who were no longer breastfeeding fell from nearly 50 per cent to only 12 per cent as a result of the project. At project end, researchers also found that women who got more vitamin A from OSP had a lower likelihood of having marginal Vitamin A deficiency.

This project was undertaken concurrently in Mozambique, where results showed even higher levels of adoption – and consumption – of OSP by vulnerable households. "We now have evidence from two very different countries and contexts that show that farming households are willing to adopt OSP, incorporate it in their diets, and get the vitamin A that they need,” says Dr. Daniel Gilligan, a senior economist at the International Food Policy Research Institute (IFPRI).

HarvestPlus is now scaling-up OSP to reach another 225,000 households by 2016. The International Potato Center (CIP) plans to scale-up OSP to reach more than 600,000 households in ten countries by 2015, including 120,000 households in Mozambique.

HarvestPlus runs similar projects with vitamin A-rich “yellow” cassava and with iron reach bean varieties in Rwanda. Both projects are promising: In January 2012, the Nigerian Government announced the release of three new vitamin A-rich ‘yellow’ cassava varieties, and the Rwandan Government released five new iron-rich bean varieties in July 2012.

Biofortification in the GGIAR programme

Biofortification is the process of breeding new varieties of foods crops that contain higher amounts of nutrients to improve nutrition and public health. Agricultural approaches, such as biofortification, are now being looked upon to fill the nutritional gap for vitamin A and other nutrients.
 
Since 1995, scientists from four Future Harvest Centers of the Consultative Group on International Agricultural Research (CGIAR) and partner organisations have been evaluating the feasibility of using modern breeding techniques to produce new varieties of staple crops with high zinc, iron, and beta carotene content with promising results.

The Biofortification Challenge Program of the CGIAR HarvestPlus Program – starting in the beginning of this century – focuses on three micronutrients that are widely recognised by the World Health Organization (WHO) as limiting: iron, zinc, and vitamin A. Full-time breeding programmes were successfully developed for six staple foods: rice, wheat, maize, cassava, sweet potatoes, and common beans.

Golden Rice was the first biofortified staple food crop. It was developed in the late 1990s by using genetic modification techniques, with genes from maize and a common soil microorganism that together produce beta carotene in the rice grain.

In 2011 and 2012, other CGIAR centres released vitamin A, iron, and zinc enriched cassava, maize, bean, and sweet potato varieties. In collaboration with national research institutes in Nigeria, Rwanda, and in Uganda, the new varieties were distributed commercially to small-scale farmers in these countries. One important aspect is that these new varieties are bred without genetic engineering, which made it easier to have them accepted by the farmers.

More  information: Article on the study in the Journal of Nutrition 

(HarvestPlus/wi)