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
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."