Biofortified crops ready for developing world debut

Orange maize boosted with beta-carotene will be released in Nigeria and Zambia in 2012 Copyright: HarvestPlus/T. Rocheford

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A range of crops rich in micronutrients will be launched from next year, but is the developing world ready for them, asks Tatum Anderson?

Millet rich in iron; wheat abundant in zinc; cassava tinged with extra beta-carotene. An array of crops bred to contain micronutrients that could fight the widespread problem of undernutrition is about to be unleashed on the developing world, beginning next year.  

The first meeting of international experts in biofortification heard last week (9–11 November) that, after almost a decade of research and development, high-iron pearl millet seeds will be released in India next year; and cassava and maize boosted with beta-carotene (which the body turns into vitamin A) will be released in Nigeria and Zambia in 2012.  Sweet potato containing extra beta-carotene is already on the market.

But will the undernourished embrace these solutions to the health problems that lack of nutrients brings? Experts at the meeting, the First Global Conference on Biofortification, are now turning their attention to winning over their customers — and they are realising there are many hurdles.

A lack of micronutrients such as iodine or zinc can lead to stunted growth, severe wasting, and intrauterine growth restriction and contributed to a large proportion of the 2.2 million deaths from undernutrition of children under five in 2005, according to a 2008 report by The Lancet.

People deprived of micronutrients usually rely on staple crops to give them sufficient calories to survive but miss out on other micronutrient-containing foods such as protein sources and vegetables. The hope with biofortification is that it could deliver these micronutrients via the very staple crops to which people do have access.

But these insights must now be explained to the outside world, says Ross Welch, a crop and soil scientist at Cornell University, United States, and a specialist in zinc-enriched wheat.

"You need to make sure the consumer will eat them, and the farmers will grow them. We need government policies to promote the planning of biofortification of crops."

Will, for example, Africans who have for generations opted for white-coloured staples, tuck into yellow and orange food rich in beta-carotene? Yellow-coloured maize varieties are often associated with animal feed.

Howarth Bouis, head of HarvestPlus, the organisation that has managed the development of many biofortified crops at a variety of research institutes around the world, thinks habits can be changed. Recent trials of biofortified orange-fleshed sweet potato in Uganda have revealed that if the benefits of vitamin A are explained to mothers, the food is consumed.

The problem, he concedes, will be spreading these messages cheaply. Talking directly to consumers is expensive and this part of the project could be more expensive than the initial breeding process, he says. 

The development community also needs persuasion. Many believe biofortification is an expensive technical fix — at a development cost of US$100 million per variety — to a problem that ought to be approached by tackling social and economic issues instead.

The key, it is thought, will be demonstrable improvements in health.

But there have been few large-scale studies seeking a direct link, in real-life settings, between eating biofortified crops and improved health. Such a trial involves feeding a small group of people to determine that levels of the micronutrient do indeed increase in their bodies.

Golden Rice, a crop biofortified with beta-carotene whose inventors hope it might help end the scourge of vitamin A deficiency-related blindness around the world, has been tested on fewer than 100 people so far. Participants have typically been given a single serving of the rice or vitamin A supplements or vegetables, to compare outcomes.

Only one effectiveness test has so far been performed on the HarvestPlus portfolio and results are not yet published.

Cooked sweet potato by Flickr/telepathicgeorge

Trials of biofortified orange-fleshed sweet potato in Uganda have revealed that, if the benefits are explained, the food is consumed


Trials such as this are needed because it is not enough for a nutrient to be present in a food. For it to pass into the bloodstream it must be in an absorbable form — it must be bioavailable.

Bioavailability is a complicated thing influenced by many factors that trials need to untangle — the soil in which the crop grows, the milling, storage, how the crop is cooked, and even the companion foods that are swallowed at the same time.  

The bioavailability of crops containing beta-carotene degrades once they have been harvested. Perhaps most elusively, existing bacteria in a person’s gut appear to affect bioavailability, which means that, around the world, the absorption of nutrients from the same crop will vary.

A team at Iowa State University, United States, presented encouraging work at the conference showing that the beta-carotene in biofortified maize is converted in the body to vitamin A at a higher rate than that of normal maize and vegetables, including carrots.

Now scientists want to know why the beta-carotene disappears out of maize at different rates depending on the variety. They also want to understand the role of pre-biotics — substances that boost the body’s rate of absorption of the micronutrients.

Inulin, for instance, is a non-digestible carbohydrate that can boost the body’s absorption of iron, zinc and other minerals. Biofortifying crops with both nutrients and pre-biotics might improve bioavailability.

Assuming the nutrients are available and the locals are persuaded to eat the plants, there are other obstacles, too.

Generally the fruits of cutting-edge technology tend to be sold at a premium, yet the pricing of these crops must be pro-poor, says Marc Cohen, a senior researcher into humanitarian policy and climate change at Oxfam America, if they are to achieve their goals.

Will biofortification outperform other weapons in the war against under-nutrition, such as hugely successful vitamin supplements, or foods such as soy sauce and salt that are fortified through industrial processes?

Donors are even considering the merits of alternatives such as zinc or iodine-boosted fertilisers that might boost the micronutrient levels in food via the soil. 

There is also a resistance to biofortification arising from its link to genetically modified (GM) crops. Golden Rice has been developed using transgenic technology. But nothing in the HarvestPlus portfolio uses GM.

The GM debate has obscured constructive discussions over appropriate biofortification research and delivery strategies, according to Sally Brooks, a researcher at the STEPS (Social, Technological and Environmental Pathways to Sustainability) centre, housed at the UK’s Institute of Development Studies.

Some believe that HarvestPlus and other global organisations have taken a top-down approach to biofortification research, in an effort to create generic technologies that might work all over the world. This means that developing country scientists and plant breeders have had little say on the kinds of crops that might be most appropriate and their insights have not been harnessed to drive the research agenda.

"There is a mis-match between a strong emphasis on impact at scale and working with local farmers," says Brooks. "They have very little say in what [a crop] looks like. It doesn’t matter whether varieties are conventionally bred or GM. The issue is the same."

But HarvestPlus says it is now engaging enthusiastically with developing country farmers.

See Letter to the editor.

See below for a video of a plenary session on progress and challenges in biofortification research given at the conference by Howarth Bouis, head of HarvestPlus: