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Health through diversity

Vegetable diversity a recipe for good health (IPGRI)
Vegetable diversity a recipe for good health

Modern agriculture has taken a handful of crops and planted them across vast areas of the world. Just three crops - maize, rice and wheat - supply nearly half of the world's food, and only 20 of the estimated 13,000 known food plants account for about 80 per cent of the world's food. These plants supply the calories we need, but this strategy has largely overlooked micronutrients and other non-nutritional factors which, it is now clear, are equally important for a healthy and long life. The many crops that are currently neglected or underutilised may hold the key.

Statistics on world hunger are given in calories - on average, about 3000 calories per day marks the transition from hungry to not. But many who have a calorie-sufficient diet are lacking essential nutrients. Known as 'hidden hunger', the results are nonetheless plain to see. Vitamin A deficiency, for example, affects as many as 50 million children in sub-Saharan Africa, and millions more in South-east Asia; symptoms, including blindness, are often severe and can be fatal. Iron and zinc deficiencies are also widespread globally. Treatments have largely focused on supplying a missing vitamin or mineral in fortified foods, but some researchers think that this may be the wrong approach. The problem has arisen because diets are restricted to a small number of foods and one or two main staples; the logical solution seems to be to move away from this trend.

According to Timothy Johns of the Centre for Indigenous People's Nutrition and Environment and the International Plant Genetic Resources Institute, this is where underutilised crops come into the picture. "Many underutilised crops contain exceptional quantities of vitamins, minerals and other nutrients. And in fact, most essential nutrient deficiencies can be eliminated by small increases in the variety of food consumed. Underutilised crops add diversity to the diet and because they are part of traditional food systems they are readily accepted."

This common-sense approach could help many millions of people who are suffering directly and indirectly from micronutrient deficiencies. Recent research in West Africa, for example, clearly linked severity of malaria with diets lacking iron, zinc, vitamin A and folic acid; malnourished children were found to be up to nine times more likely to die from the disease, which kills more than a million people in sub-Saharan Africa each year.

Nutrition transition

Traditional diets, with their rich diversity based on local food crops, are under threat along with other traditional aspects of life in an increasingly globalised world. The trend to urbanisation in particular is associated with poor diet. More refined carbohydrates, more fats and oils, and less fruit and vegetables are the pattern; and soaring levels of diet-related diseases are the result. Termed the 'nutrition transition', this is an increasingly worrying scenario for individuals and governments alike, particularly with the projected boom in urban populations in the coming decades. A key part of the solution, says Johns, lies in greater use of plant biodiversity. And, he points out, it is not just nutritional benefits that diverse diets offer. "Data is emerging that many fruits, vegetables, legumes and traditional cereals offer additional health benefits such as anti-oxidant and anti-diabetic properties," he says. "These so-called functional properties are especially important in urban areas where diets are becoming simplified."

Science is gradually adding to anecdotal evidence for health-promoting properties of foods. Foods based on buckwheat and finger millet, for example, are known to reduce the risk of heart disease, while bitter gourd and fenugreek contain compounds that directly improve the body's ability to respond to insulin. And the presence of carotenoids such as lycopene and lutein in green leafy vegetables, which have recently been shown to play an important role in preventing cataracts, means these foods are doubly important in tackling blindness in at-risk groups; they also contain beta-carotene, a precursor of vitamin A.

Johns and his fellow researchers believe that preserving or restoring traditional food systems where locally available minor crops play a significant part in diets is the way forward. "We believe that diets in the future will increasingly depend on complementing staple energy foods such as wheat, rice, edible oil and sugar with these quality foods," he says. "Underutilised species are locally available resources that can contribute to rural and urban diets, at both a local and national level."

Date published: November 2004


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