The World Health Organization (WHO, 1973) reviewed several investigations of adult diets and
reported the average daily consumption of manganese to range from 2.0-8.8 mg Mn/day. Higher
manganese intakes are associated with diets high in whole-grain cereals, nuts, green leafy
Integrated Risk Information System (IRIS) U.S. Environmental Protection Agency
Chemical Assessment Summary National Center for Environmental Assessment
4
vegetables, and tea. From manganese balance studies, the WHO concluded that 2-3 mg/day is
adequate for adults and 8-9 mg/day is "perfectly safe."