Case study

DFID Research: sweet Solutions to boost Vitamin A

Nutritious new varieties of sweet potatoes have been developed for Africa.

Orange-fleshed sweet potato is a good source of vitamin A
Orange-fleshed sweet potato is a good source of vitamin A. Picture: NRI

Mrs. Mwanzi lives in a village near Alupe in Kenya. There she grows a new orange-fleshed variety of sweet potato, which she heard would improve her children’s health.

The oranged-fleshed sweet potato is a lifesaver for millions in East Africa. Throughout Africa, 3 million young children suffer blindness because they lack vitamin A. Two-thirds of children with Vitamin A deficiency die because of their increased vulnerability to infection. Adding the sweet potato to the daily diet of prospective mothers can also reduce maternal mortality and lower the risk of mother-to-child transmission of HIV/AIDS. The sweet potato can help prevent vitamin A deficiency because it is a good source of vitamin A.

Local farmers like Mrs. Mwanzi like the orange-fleshed sweet potato because once the plant has put down roots, a family can start eating it. An established patch keeps producing for months, so it can be harvested gradually. To make sure that she gets the first new roots early, Mrs. Mwanzi has planted a nursery for the dry season. As she says, “It is best to plant a lot of stems in case some of them die.”

However, people in East Africa tend to like white-fleshed sweet potatoes which are not as rich in vitamin A as the orange-fleshed variety. Scientists conducted an 11-week study of a group of children, and found that, among those who were given orange-fleshed sweet potatoes, the proportion with adequate stores of vitamin A increased by 10%. Among those who ate only the white-fleshed variety, that proportion fell by 5%.

New variety developed for African tastes

That is why the International Potato Centre (CIP) developed an orange-fleshed variety which appeals to East African tastes. They set up a programme to encourage farmers to cultivate and then feed the vitamin-A enriched sweet potatoes to their children. The programme has become an effective weapon for tackling vitamin A deficiency because the new varieties provide a record measure of beta-carotene nutrients. Scientists in Uganda found that just 100 grams of sweet potato for any child under the age of 2 years, is enough to provide the required daily allowance of vitamin A. Besides being rich in vitamin A, orange-fleshed sweet potato is also a good source of vitamin C, natural sugars and carbohydrates.

The Vitamin A for Africa Programme has been most effective in Uganda, Kenya, Mozambique and Tanzania and, by the end of 2004, an estimated 2 million Ugandans were eating the new varieties of sweet potato. However, the programme may have potential in countries that are not major sweet potato growers, such as Ethiopia, where new varieties are being promoted.

DFID provides support to CIP through its support of the CGIAR centres.

Published 25 May 2007