Tin or stannum in Latin, is essential in some mammals, including rats, but it has not been shown to be needed in humans. It is more often considered a mildly toxic mineral. One of the reasons its essentiality is questionable in humans is its absence in newborns and in many animals. It is present in the earth in very small amounts. Tin is most often thought of as an environmental contaminant, both as tin cans and as inhaled industrial pollution. Levels, especially in the lungs, increase with age.

Source: Elson M. Haas M.D. (Excerpted from Staying Healthy with Nutrition: The Complete Guide to Diet and Nutritional Medicine)