I began taking kelp as a source of iodine, I noticed an immediate improvement in my weight loss but I began to suffer with sinus issues and had very low energy. After a few days a thick white coating with an odd taste appeared on my tongue. I think it might have been a case of mercury contamination in kelp "feeding" yeast overgrowth. I've not suffered with any type of yeast overgrowth before and having gone off the kelp, my symptoms have alleviated.