About 70% of American households regularly use iodized salt. If you are one of them, the latest debate on the benefits of iodine supplementation may interest you. A Chinese study, published in The New England Journal of Medicine, found that over time increased iodine intake was linked to decreased thyroid function. Yet not all doctors agree with the study's findings. Robert Utiger, MD, a thyroid expert at Harvard Medical School and Brigham and Women's Hospital in Boston dismisses these conclusions as "overcautious," stating that low iodine intake is more problematic than excessive consumption. So before you start supplementing, you may want to consider how much iodine you normally take in through foods. Fish and dairy products are rich natural sources of iodine, as are some seaweeds.