Uganda: Orange Sweet Potato Makes the Case For Biofortification, Says Study

By Jepkemei Gachomo

KAMPALA--A study published recently in the Journal of Nutrition shows conclusive evidence that orange sweet potato (OSP) provided significant amounts of vitamin A to malnourished Ugandan children and women and that a modest improvement in vitamin A levels in the body was measurable in some cases.

Vitamin A deficiency (VAD) 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, VAD prevalence is estimated at 42 per cent among children under five with Uganda being among the countries reported to be at high risk with 28 per cent of children and 23 per cent of women estimated to be vitamin A deficient.

Deficiency in vitamin A can impair immunity and cause eye damage that can lead to blindness and even death. Annually, up to 500,000 pre-school children go blind from VAD, and about two-thirds will die within months of going blind.

Biofortification is the process of breeding new varieties of foods crops that contain higher amounts of nutrients to improve nutrition and public health and such processes are now being looked upon to fill the nutritional gap for vitamin A and other nutrients.

Traditionally, white or yellow sweet potato varieties are grown and eaten in Africa, but these provide little, or no, vitamin A. OSP was conventionally bred, not just to provide more vitamin A but also to be high yielding and drought tolerant.

From 2007–2009, HarvestPlus and its partners disseminated new OSP varieties to more than 10,000 farming households in Uganda for whom sweet potato is a key staple food, in a project that 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, which is available for about 10 months a year, can be a rich and steady source of vitamin A.

 
The project resulted in 61 per cent of households adopting the vitamin A-rich OSP to grow on their farms and the 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.
 
Vitamin A intake increased by two-thirds for older children and nearly doubled for younger children and women by project end. For children 6–35 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 aged between 12 – 35 months who were no longer breastfeeding fell from nearly 50 per cent to only 12 per cent as a result of the project.

The results of the study are positive as young children who have recently stopped breastfeeding are at higher risk of VAD because breast milk has been their primary source of vitamin A and their vitamin A needs continue to be high.

Researchers were also able to measure a small positive impact of eating OSP on the amount of vitamin A in the blood among children aged between 5 – 7 years that had lower levels of vitamin A at the start of the project. At the end of the project, researchers also found that women who got more vitamin A from OSP had a lower likelihood of having marginal VAD even though vitamin A deficiency was unexpectedly low among the women sampled in this study, thus making it harder to detect changes.

“Overall, these results add to the growing evidence base that OSP provides large amounts of vitamin A in the diet. We were also able to show a modest increase in vitamin A blood levels among children, despite this being challenging to measure given the changing nutritional landscape over two years under real-world conditions,” said Dr. Christine Hotz, former HarvestPlus Nutrition Head who led the nutrition study in a media release.
 
This project was undertaken concurrently in Mozambique where results showed even higher levels of adoption and consumption of OSP by vulnerable households.

HarvestPlus is now expanding OSP to reach another 225,000 households by 2016 while International Potato Center (CIP) plans to scale-up OSP to reach more than 600,000 households in 10 countries by 2015, including 120,000 households in Mozambique.

From 2007-2009, HarvestPlus and its partners disseminated orange sweet potato to see whether VAD could be reduced to more than 24,000 households in Mozambique and Uganda.

HarvestPlus leads a global effort to breed and disseminate staple food crops that are rich in vitamins and minerals to improve nutrition and public health. Using a process called biofortification, higher amounts of vitamins and minerals are directly bred into foods such as bean, cassava, sweet potato, rice, maize, pearl millet, and wheat.

HarvestPlus is part of the CGIAR Research Program on Agriculture for Nutrition and Health (A4NH). It is coordinated by CIAT and the International Food Policy Research Institute (IFPRI).