This is how a new crisis begins.
When scientists concentrate certain elements in a food, they can combat the deficiency of those elements.
But then they start a new imbalance for thousands of other chemicals in that food.
In less than 10 years, consumers throughout Brazil will have access to eight biofortified "superfoods" being developed by the country's scientists. A pilot scheme is under way in 15 municipalities.
Biofortification uses conventional plant-breeding methods to enhance the concentration of micronutrients in food crops through a combination of laboratory and agricultural techniques.
The goal is to combat micronutrient deficiencies, which can cause severe health problems such as anaemia, blindness, impaired immune response and development delays. According to the UN Food and Agriculture Organisation, micronutrient malnutrition affects 2 billion people globally.
These efforts in Brazil began a decade ago, when the government agricultural research agency, Embrapa, initiated the biofort project as part of an international alliance for the development of crop varieties with higher concentrations of essential micronutrients. Embrapa chose eight foods that are staples of the Brazilian diet: rice, beans, cowpeas (black-eyed peas), cassava, sweet potatoes, corn, squash and wheat.
"We are working on increasing the iron, zinc and provitamin A content. These are the nutrients most lacking not only in Brazil, but in the rest of Latin America and the world as well, the cause of what we call hidden hunger," food engineer and a biofort co-ordinator, Marília Nutti, told Tierramérica*. Iron is key. Half of Brazil's children suffer from some degree of iron deficiency, said Nutti.
The scientists are working on breeding plants of the same species, choosing seeds that exhibit the best traits in terms of micronutrient content.
"This is not transgenics. We want a varied diet. Biofortification attacks the root of the problem and is aimed at the poorest sectors of the population. It is scientifically viable and economically viable as well," she said.
The project is supported by HarvestPlus and AgroSalud, research programmes that are operating in Latin America, Africa and Asia with funding from the Bill and Melinda Gates Foundation, the World Bank and development agencies.
How much more nutritious are these new foods? The iron content of the beans, for example, has been raised from 50 to 90 milligrams of iron per kilogramme. The cassava, which normally contains almost no beta-carotene, now has nine micrograms of this vitamin A source per gram.
The beta-carotene content of sweet potatoes has been boosted from 10 micrograms per gram to a whopping 115. And the zinc content of rice has been enhanced from 12 to 18 milligrams per kilo.
In Itaguaí, an industrial municipality 44 miles south of Rio de Janeiro, about 8,000 pre-school children are benefiting from these extra-nutritious foods.
Embrapa focused on eight staples of the Brazilian diet including sweet potatoes, corn and wheat. Photograph: Nacho Doce/Reuters
With an estimated population of 110,000, Itaguaí has an annual gross domestic product of $14,000. These conditions made it an ideal location for Embrapa to kick off the project, distributing the food grown to the municipality's public schools, where it is used to prepare school lunches.
For now, the municipality is growing sweet potatoes, squash, beans and cassava on a 1 hectare (2.47 acres) plot that is also used to train the family farmers who supply the schools.
The municipal secretary of environment, agriculture and fisheries, Ivana Neves Couto, said: "Itaguaí is a model municipality. This is the third year in a row that we have won the award for the best school lunch management. We have very ambitious plans to quickly reach the entire municipal education system in partnership with all of the family farmers."
The system encompasses 62 schools and 17,000 students. In 2010, the local authorities incorporated the nutrient-enriched foods in school lunches at 13 pre-school centres, with a total enrolment of about 8,000 children.
The goal is to include all of the municipality's family farmers in the project, and within two years to offer biofortified foods in all of its schools, as well as stores and public markets in the city.
One factor that works in favour of the new foods is the natural curiosity of children. "When we tell them that these foods have more vitamins, and they see the deeper colours [of the biofortified crops], they are eager to try them out," Couto told Tierramérica.
Brazil is the only country working with eight biofortified crops. Bangladesh, Colombia, India, Mozambique, Nicaragua, Pakistan, Peru, the Democratic Republic of the Congo and Uganda are conducting research on one crop each.
The challenge, said Nutti, is for biofortification to be adopted as a matter of national policy for the promotion of food security, after the example of Panama, which has incorporated it on the government agenda.
The Brazilian initiative is in the pilot stage of cultivation, with crops grown in 11 states. A total of 15 municipalities are using the food for school snacks and lunches.
Although the project was initiated in Itaguaí, the focus for the future is on states in the north-east, such as Maranhão, Piauí and Sergipe, Brazil's poorest.
There are 67 farming units and 1,860 family farmers directly involved in the production of biofortified crops. This is a rather small scale for a country with 5,570 municipalities and a population of about 200 million.
A diet lacking in iron and zinc can cause anaemia, reduced work capacity, immune system impairments, development delays, and even death. Anaemia is the leading nutrition-related problem in Brazil.
About $10m has been invested in the Embrapa project, which involves 15 universities, as well as research centres and municipal governments.
Next year, the agency plans to carry out an assessment of the project's nutritional impact on the population, by measuring the results achieved with its superfoods in comparison with conventional food crops.