Despite the rapid progress made towards reducing poverty in many developing countries in recent years, high rates of malnutrition persist – and Vitamin A deficiency remains a persistent challenge. One cause for optimism is that new approaches to ‘biofortification’ are beginning to offer hope of improved strategies with the potential to save tens to hundreds of thousands of lives per year.
To recap, the problem, as described by the World Health Organisation:
“Vitamin A deficiency (VAD) is the leading cause of preventable blindness in children and increases the risk of disease and death from severe infections. In pregnant women VAD causes night blindness and may increase the risk of maternal mortality.
An estimated 250 million preschool children are vitamin A deficient and it is likely that in vitamin A deficient areas a substantial proportion of pregnant women [are] vitamin A deficient. An estimated 250,000 to 500,000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight.”
These numbers are striking, and show beyond doubt that tackling this problem urgently is surely one of our greatest moral challenges. With a quarter to half a million children going blind each year from vitamin A deficiency, and half of them dying within 12 months, this implies an annnual death toll of 125,000 to 250,000 children – a staggering mortality rate for this little-known affliction.
So what strategies might work?
WHO promotes an ‘arsenal’ of nutritional weapons, including “a combination of breastfeeding and vitamin A supplementation, coupled with enduring solutions, such as promotion of vitamin A-rich diets and food fortification”. Vitamin A supplements in the form of capsules to young children are highly effective but time-limited – their effects last only 4-6 months, so WHO says “they are only initial steps towards ensuring better overall nutrition and not long-term solutions”.
Instead, “food fortification takes over where supplementation leaves off. Food fortification, for example sugar in Guatemala, maintains vitamin A status, especially for high-risk groups and needy families.” Fortification means artificially mixing in vitamin A with foods which people buy and consume, and as the WHO suggests, it can play a major role. One example of a current initiative is the effort – supported by Helen Keller International – to add vitamin A to cooking oil in West Africa.
A complementary approach is ‘biofortification’, where the missing nutrients are bred into staple crops either through conventional selective breeding or – if no genes are availble in related plants – through genetic engineering. As HKI puts it:
“Biofortification differs from large-scale food fortification because it focuses on growing more nutritious plant food, as opposed to adding micronutrients to foods as they are commercially processed.”
Biofortification is particularly useful for reaching the rural poor who grow the food they consume, and are therefore largely outside the reach of food fortification programmes, which work best in urban areas where most food is purchased in markets. Unlike supplements, biofortified vitamin A-enriched food and crops will continue to protect children from deficiencies in a sustainable way at little extra cost as they are harvested each year.
Although it has been a long time in development, vitamin A-enriched ‘golden rice’ could soon be a breakthrough intervention in south and east Asia, where the largest-scale deficiency problem persists. It has now been scientifically established that golden rice “is an effective source of vitamin A” (to quote from the title of Tang et al, 2009, Am. J. Clin. Nutr) and thereby potentially an effective intervention to save lives in areas where white rice is the staple food. (Technically golden rice, like other vitamin A-fortified foods, contains enhanced levels of beta-carotene, the precursor to vitamin A.)
Even so, continued opposition threatens to derail this progress. Much of this focuses around the idea that other approaches to vitamin A deficiency are more ‘appropriate’ than one involving GMOs and should be tried first. This seems to me to run counter to the WHO’s ‘arsenal’ approach – why not try everything you can in response to a crisis which takes the lives of up to a quarter of a million young children per year? A common variant is the ‘let them eat broccoli’ argument (with apologies to Marie Antoinette) – that promoting a more balanced diet is more appropriate than fortification of staple foods.
No-one disputes that a balanced and nutritionally-adequate diet is the best long-term soluton to vitamin A deficiency and malnutrition in general. But achieving this requires the elimination of poverty (which is why rich countries do not have this problem), something which will take time and decades of economic growth in the developing world. In the meantime, millions of preventable deaths will occur, and many of those children that survive will have their life prospects permanently harmed.
A useful analogy might be providing water and sanitation – another issue which can only be solved permanently by povery elimination. As far as I know, no-one argues that charities are wrong to provide clean water in African villages because it this is merely a short-term ‘fix’ for a long-term problem. (And dirty water is the biggest killer of all.) The challenge is to save lives of vulnerable people right here, right now, in any way that works.
That biofortification of staple foods can help achieve this is already being demonstrated in the real world in east Africa, where the Bill & Melinda Gates Foundation has supported a global effort called HarvestPlus to distribute orange-fleshed sweet potato (OFSP – not unlike the sweet potatoes eaten in the US) to tens of thousands of households in rural Mozambique and Uganda as an initial proof of concept.
The background is that the traditional varieties of sweet potato (a key staple food) eaten in these two countries are white or yellow fleshed and deliver little or no vitamin A – the main reason, together with poverty and a lack of dietary diversity, why a quarter of pre-school age children are deficient in this vital nutrient. The new orange-fleshed sweet potato is also high-yielding and drought tolerant, and in Mozambique and Uganda was quickly snapped up by a large majority of rural households to whom it was offered for growing on a trial basis.
“The project resulted in 61% of households adopting the vitamin A-rich OFSP to grow on their farms. They were also willing to substitute more than one-third of their traditional white and yellow sweet potato consumption with OFSP. 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, OFSP contributed more than 50% of their total vitamin A intake.”
The results of the scientific study to evaluate the impacts of the project have recently been published in the Journal of Nutrition (Hotz et al, 2012). A second trial rollout in Mozambique has been equally successful, with two-thirds of the 10,000 households targeted in Zambezia province adopting the new variety, with dramatic increases reported in childrens’ vitamin-A consumption as a result (Hotz et al, 2012, British Journal of Nutrition).
HarvestPlus is also just beginning to deploy vitamin A cassava in Nigeria and vitamin A maize in Zambia, as test countries. Iron beans have been released in Rwanda and iron pearl millet in India. Zinc rice and wheat will follow soon in South Asia. (For more on all these initiatives see the HarvestPlus website.)
Because orange-fleshed sweet potato and the other crops developed by HarvestPlus are produced with conventional breeding, they have not been subject to anti-GM opposition or unfounded fears about food safety. Golden rice, because it uses a transgenic approach to biofortification, still faces opposition – despite the clear scientific consensus that GM is not a food safety issue, and, as the recent AAAS statement put it, “crop improvement by the modern molecular techniques of biotechnology is safe”.
I am hopeful however that opposition has now begun to ebb, and that the successes recently demonstrated in Africa will convince doubters to come round to the potential of biofortification. As the Philippine Rice Research Institute has reported, field trials of golden rice in the Philippines to date have been successful. Over the next couple of years, the new locally-adapted varieties will be put through the national regulatory process, and if deemed safe, continue through actual community, consumer and grower trials toward full deployment to those who could benefit most. (See here for a detailed FAQ about golden rice and vitamin A deficiency.)
Public acceptability will be crucial in any roll-out of golden rice, given the intense public concerns focused over many years on the GMO issue. In the couple of years that are left before golden rice goes on offer to consumers and growers in the Philippines, I hope the good news from Africa will help give a much-needed boost to public understanding of the life-saving potential of biofortification in food crops.