I LOVE ACV and use it daily but at one point, I had also cut out salt with iodine from my diet. I didn't realize that I needed to get iodine from another source (sea kelp, soy milk, etc). After approximately a year and a half, I developed a goiter on my thyroid (August 2011). My doctor scheduled a neck ultrasound for me and I knew that the next step was a blast of radiation (the goiter was big). I did research (ON THIS SITE ESPECIALLY! ) and found out that long term use of ACV can leach the iodine from your body. I also discovered the connection between iodine and thyroid function. I immediately started taking kelp powder. My doctor was skeptical but after a few weeks, the goiter started decreasing in size. It was almost gone by the time I went for the ultrasound. My doctor was amazed :) He said that the ultrasound showed that I still had 5 nodules on my thyroid but my recent bloodwork showed that my thyroid is fine! I still take ACV but I now make sure to replace the iodine in my body.