August 27, 2001
Phone: (504) 865-5714
Nearly half of the world's women are chronically anemic, approximately 600 million people show signs of iodine deficiency, and about a quarter of the children in developing countries suffer from a lack of vitamin A. All over the globe, people are negatively affected by the lack of minute amounts of basic nutrients.
John Mason, professor of international health and development, is the lead author of a new survey of micronutrient deficiencies across the planet. The Micronutrient Report: Current Progress and Trends in the Control of Vitamin A, Iodine, and Iron Deficiencies was published this spring by the Micronutrient Initiative in Ottawa, Canada.
"What we've done, more than estimating the levels of micronutrient deficiencies around the world, is to estimate the trends. Clearly, it's very different if you've got a bad situation getting worse or getting better," Mason said. "For both vitamin A and iodine, there are massive programs being implemented worldwide, and it's important to know whether they're effective or not."
Mason and his co-authors compiled and analyzed data on the current state of the most commonly recognized micronutrient deficiencies. Iron deficiency is the main cause of anemia, though not the only cause. Lack of vitamin A can cause blindness and contributes to other health problems, especially increased mortality rates in children and pregnant women. The most visible sign of iodine deficiency is goiter, but, more significantly, it is the most preventable cause of mental retardation.
"These deficiencies are mainly due to inadequate diets," Mason said. "Poor people have to eat the cheapest foods, which tend to be those that are least rich in nutrients. Their first priority is to get enough food not to be hungry."
The most practical solution in many places is to fortify staple foods with the missing nutrients. Iodized salt is the most commonly fortified food. Salt is the perfect vehicle for iodine, which needs to be consumed daily in very small amounts.
Salt is used everywhere. The only problem is that not all commercial salt is iodized, and even in places like China, where the government enforces iodization, poor people find it more economical to find their own salt from natural sources. Vitamin A is a fat-soluble nutrient that can be given in large doses twice a year, so supplementation can be used to fill in the gap until widespread fortification can be developed.
Iron presents the greatest problem. It is needed daily and it can be tricky to get enough iron on a vegetarian diet, because of the low biological availability in vegetables. In places where people are vegetarians and very poor, iron intake is very low. Wheat can be supplemented with iron, but an effective way of fortifying rice with iron has not yet been developed.
Mason expects Tulane to be part of a large-scale project on fortification that will begin next year. And he's hopeful that a solution is in sight for at least some micronutrient deficiencies.
"It's likely that the first big public health achievements this century--comparable to the eradication of smallpox in the 1900s--are going to be elimination, first of all, of iodine deficiency and, secondly, vitamin A deficiency," he said.
His colleague, Jack C. Ling, is actively involved in the elimination of iodine deficiency. Ling, a clinical professor of international health and development and the former director of the Information and Communication Division of UNICEF, has been elected chair of the International Council for the Control of Iodine Deficiency Disorders.
Ling said the key to eliminating iodine deficiency is comprehensive and sustained communication in order to bring about permanent changes in behavior.
"Salt iodization doesn't solve the problem if people don't use it," Ling said. "You cannot solve the problem by stealth, you have to let people know why they are doing it. Then they will change their behavior."
China, for example, has an apparently successful salt iodization program. But many people there don't understand the importance of iodine. The majority of people in some provinces associate iodine deficiency with visible goiter but don't understand the risk it poses for brain damage, so they will choose non-iodized salt if they can get it more cheaply. Ling believes it would help if shopkeepers who sell salt were educated about the issue so they could talk about it with their customers.
"It's not a very complicated story," Ling said. "It's the most prevalent, most preventable cause of brain damage in children. All you need is iodized salt, but you have to take it every day."
The Micronutrient Report can be found at http://www.micronutrient.org/frame_HTML/resource_text/pub lications/mn_report.pdf or it can be accessed through www.tulane.edu/~internut, which has other information on this and related projects.
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