Yes. Any excessive mineral or vitamin intake can be harmful, no matter your age. In children it’s especially important because their teeth are still developing. In areas where fluoride is naturally high in the soil, special filtration may be needed. If you are on a well water system, it’s important to ensure that fluoride levels comply with state or federal mineral guidelines, so that steps can be taken if it is too high or too low. If too little, teeth and bones can be extremely weak; too high, excessive mineralization can cause unsightly brown coloration and pits within the mature enamel.