Dietary Iodine: Why Are So Many Mothers Not Getting Enough?
Dietary Iodine: Why Are So Many Mothers Not Getting Enough?
Maternal iodine deficiency has been associated with a number of adverse effects on the infant brain resulting in a continuum of effects depending on the degree of iodine deficiency, from lowered IQ to severe mental retardation. The thyroid gland uses iodine to make thyroid hormones, which in turn direct brain development. Insufficient iodine is considered the leading cause of preventable mental retardation in the world, and iodine deficiency in pregnant women has been estimated to result in the loss of some 10–15 IQ points at the global population level.
Data collected over the last 30 years through the National Health and Nutrition Examination Survey (NHANES) suggest iodine levels in the U.S. population, particularly among women of childbearing age, may be getting too low, according to epidemiologist Kevin Sullivan of Emory University. The good news is that, in the past, concerted efforts to ensure adequate iodine intake have yielded beneficial effects. The task now is to understand why so many women are deficient in iodine—and what it will take to make sure pregnant women get enough.
Switzerland, with centuries of serious iodine deficiency, introduced iodized salt in 1922, two years before the U.S. FDA. Unlike in the United States, 60% of Swiss processed foods are made with iodized salt, and almost all the table salt used in Switzerland is iodized. Switzerland monitors iodine levels in the population once every five years and adjusts salt iodine levels accordingly. In 1998 the country increased the salt iodine level in response to reports of marginal iodine status among pregnant women and schoolchildren. The response was a corresponding rise in urinary iodine to "clearly sufficient" status, and also a more normal level of thyroid function in newborn infants.
Abstract and Introduction
Introduction
Maternal iodine deficiency has been associated with a number of adverse effects on the infant brain resulting in a continuum of effects depending on the degree of iodine deficiency, from lowered IQ to severe mental retardation. The thyroid gland uses iodine to make thyroid hormones, which in turn direct brain development. Insufficient iodine is considered the leading cause of preventable mental retardation in the world, and iodine deficiency in pregnant women has been estimated to result in the loss of some 10–15 IQ points at the global population level.
Data collected over the last 30 years through the National Health and Nutrition Examination Survey (NHANES) suggest iodine levels in the U.S. population, particularly among women of childbearing age, may be getting too low, according to epidemiologist Kevin Sullivan of Emory University. The good news is that, in the past, concerted efforts to ensure adequate iodine intake have yielded beneficial effects. The task now is to understand why so many women are deficient in iodine—and what it will take to make sure pregnant women get enough.
Switzerland, with centuries of serious iodine deficiency, introduced iodized salt in 1922, two years before the U.S. FDA. Unlike in the United States, 60% of Swiss processed foods are made with iodized salt, and almost all the table salt used in Switzerland is iodized. Switzerland monitors iodine levels in the population once every five years and adjusts salt iodine levels accordingly. In 1998 the country increased the salt iodine level in response to reports of marginal iodine status among pregnant women and schoolchildren. The response was a corresponding rise in urinary iodine to "clearly sufficient" status, and also a more normal level of thyroid function in newborn infants.
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