Sweet potatoes to let you see in the dark

Sweet potatoes are a staple food in many parts of the world, particularly in hot climates where they grow well. There are white-fleshed ones and orange-fleshed ones. The orange-fleshed ones help people’s eyesight.

Orange-fleshed sweet potatoes (OFSP) contain carotene. It makes them orange and it makes them good for eyes. Other parts of the body, too. Here’s how: when a person eats carotene, the body turns it into Vitamin A. That vitamin is essential for the eyes and for the immune system. If your mother told you to eat orange-coloured vegetables to let you see in the dark, she was talking about Vitamin A.

The World Health Organization says that 285 million people are visually impaired and 90% of those people live in developing countries. That’s partly because Vitamin A deficiency (VAD), and the eye problems it causes, are conditions of poverty.

VAD is one of the most common causes of childhood blindness. This starts early. The 1000 Days Movement tells us that Vitamin A is particularly important during pregnancy and early childhood. UNICEF agrees through its Childinfo website. There, UNICEF tells us that 33% of preschool-age children and 15% of pregnant women have VAD. UNICEF provides data to show that this is about poverty. Showing a map, UNICEF says, ‘The highest prevalence and numbers [of VAD] are found among countries of sub-Saharan Africa and South East Asia.’

Here comes the heroic sweet potato (Ipomoea batatas). Three weeks ago I wrote about Helen Keller International, a non-governmental organisation devoted to preventing blindness and reducing malnutrition. One of its strategies is to promote OFSP. Here’s some science about OFSP improving young kids’ Vitamin A status concluding, ‘Consumption of OFSP improves vitamin A status and can play a significant role in developing countries as a viable long-term food-based strategy for controlling vitamin A deficiency in children.’

All About Sweet Potatoes tells us the history and origin of I. batatas. This is a nutritious vegetable which is important in many countries. Let me tell you that I. batatas isn’t a yam. It’s known as ‘yam’ in some parts of North America, but from a botanist’s point of view, it’s dramatically different from the true yam (Dioscorea macrostachya and other species in that large genus). Here’s a history of how the names became confused. I. batatas isn’t a potato, either – the true potato is Solanum tuberosum.

All very interesting but the sites I’ve just linked to don’t mention what’s special about OFSP. For that, you might want to look at the International Potato Center (called CIP, its Spanish acronym). CIP takes a worldwide view and tells us how all kinds of roots and tubers can improve poor people’s lives. Here’s what CIP says about I. batatas.

I. batatas can let you see in the dark, if you eat the orange-fleshed kind. OFSP promotions are working in sub-Saharan Africa. Here’s a film about OFSP in Tanzania. Here’s another film about OFSP in Ghana.

But many poor people, hence many people with VAD, live outside Africa. Eating OFSP is surely needed in Asia. CIP is responding to the Asian need. ‘Approximately 45 percent of the world’s… children and pregnant women [with VAD] live in South and Southeast Asia… the use of [OFSP] in Asia to combat VAD is not yet as advanced as it is in Africa, [but] CIP is introducing varieties that are rich in Vitamin A along with successful outreach programs promoting their consumption.’

So the selectively bred OFSP is being promoted in Africa and, increasingly, in Asia too. In Asia it has to compete for market share with a biotech product, genetically modified Golden Rice (GR). My fellow blogger Janina at Food (Policy) for Thought has an open mind about GR and I too have an open mind.

The International Rice Research Institute (IRRI), based in the Philippines, promotes GR. In contrast Africa Rice, with offices in several sub-Saharan countries, doesn’t promote GR.

What I’m seeing is OFSP for Africa and GR for Asia. People grow and eat sweet potatoes in both of these continents; people grow and eat rice in both of these continents; people need more Vitamin A in both of these continents.

If you know why Africa is being offered Orange-Fleshed Sweet Potatoes to improve sight, whereas Asia is being offered Golden Rice, do please let me know.

[Edit] You might choose to watch the WordPress blog about the third African Rice Congress. Or go to that Congress, if you can. It’s to be held in October this year. I won’t be there but I’ll be watching.