A poor diet that lacks essential nutrients generally causes nutritional deficiencies. The body stores nutrients. Therefore, a deficiency is usually detected after a prolonged lack of a nutrient. A number of diseases and conditionsâincluding colon cancer and gastrointestinal conditionsâcan lead to an iron deficiency.
Iodine is LIKELY SAFE for most people when taken by mouth at recommended amounts or when applied to the skin appropriately using approved products. Iodine can cause significant side effects in some people. Common side effects include nausea and stomach pain, runny nose, headache, metallic taste, and diarrhea.
High doses of selenium can cause significant side effects including nausea, vomiting, nail changes, loss of energy, and irritability. Poisoning from long-term use is similar to arsenic poisoning, with symptoms including hair loss, white horizontal streaking on fingernails, nail inflammation, fatigue, irritability, nausea, vomiting, garlic breath odor, and a metallic taste.