Manganese - a scoping review for Nordic Nutrition Recommendations 2023

Manganese is an essential trace element that is required for multiple enzymes in the human body. The general population is mainly exposed to manganese via food intake, in particular plant foods. In areas with elevated concentrations of manganese in groundwater, drinking water can also be an important source of exposure. The gastrointestinal absorption of manganese is below 10%, and it appears to be influenced by the amount of manganese in the diet and by the nutritional status of the individual, especially the iron status. In blood, most of the manganese is found in the cellular fractions. Manganese is primarily eliminated via the bile followed by excretion via faeces. To date, no specific biomarkers of manganese intake have been identified. The dietary intake of manganese in the Nordic countries has been reported to be within the range that has been reported for other European countries (2-6 mg/day). Since manganese is found in nutritionally adequate amounts in food, deficiency is not of public health concern. On the other hand, there is emerging epidemiological evidence that various suggested manganese biomarkers may be negatively associated with children's neurodevelopment. However, the limited number of prospective studies, the lack of appropriate exposure biomarkers, and validated neurodevelopmental outcomes render data uncertain and inconclusive. In 2013, the European Food Safety Authority considered the evidence to be insufficient to derive an average requirement or a population reference intake, and instead an adequate intake for adults was set at 3.0 mg/day.