Iodine can turn blue-black when it interacts with starch or carbohydrates, but the discussion raises questions about other substances, like cellulose in toilet paper, that might also cause this reaction. A health company claims their alkaline water acts as an antioxidant, causing iodine to turn blue-black instead of colorless, which contradicts typical chemical behavior. Experts suggest that iodine should turn colorless when reacting with an antioxidant, indicating something is amiss with the company's claims. The skepticism towards the health company's assertions points to a broader concern about the validity of such products. Overall, the conversation highlights the need for critical evaluation of health claims related to chemical reactions.