1. Iodine By: Brittany Daigle

2. Deficiency Symptoms: Extreme fatigue, goiter, mental slowing, depression, weight gain, and low basal body temperatures. Iodine deficiency is the leading cause of preventable mental retardation. Other possible things that can happen because of iodine deficiency: Breast Cancer and Stomach Cancer

3. Toxicity Poisonous if taken orally in larger amounts: 2-3 grams of it is a lethal dose for a adult human. Excess iodine has symptoms similar to those of iodine deficiency.

4. Function Controls metabolism, normal thyroid function, and for the production of thyroid hormones.