MIOD

Iodine (I) deficiency is estimated by WHO to be the leading cause of preventable mental retardation worldwide. Switzerland was severely I deficient until iodized salt was introduced in 1922. National surveys in 1999, 2004 and 2009 have generally shown sufficient I intake in school aged children and pregnant women but other population groups such as weaning infants and women of reproductive age have low intakes. Along with iodized salt, milk and dairy products are the main I sources in Switzerland, supplying more than half of intakes, and the population would be I deficient without this important contribution. However, milk products are an unpredictable source: I concentrations of milk vary widely between seasons and production methods, with organic products generally showing lower concentrations. Therefore, this project will investigate the key factors that influence the iodine content of milk, from the dairy cow, through processing, to human consumption. The project goal is to provide new data for recommendations for dairy cow I supplementation and milk processing in order to achieve a specified range of I concentration in milk products, so that I intake by target populations in Switzerland are adequate, avoiding both I deficiency and I excess. This project has three sections: 1) To determine the dose-response of iodine supplementation to dairy cow diets onmilk I concentration, specifically in the lower feed I concentrations used in organic production; 2) to investigate the effect of processing of milk with varying I concentration on I content in dairy foods such as yogurt and cheese in order to minimize losses; and 3) to use a new method of labeling milk with the I tracer 129I (entails no health risk), in order to directly quantify I bioavailability from milk in humans for the first time. With these three approaches, three major gaps in knowledge will be closed.