Biofortified crops ready for developing world debut

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.

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?