Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2003
Publication Date: 9/1/2003
Citation: Finley, J.W., Penland, J.G., Pettit, R.E., Davis, C.D. 2003. Dietary manganese intake and type of lipid do not affect clinical or neuropsychological measures in healthy young women. 2003. Journal of Nutrition. v.133. p.2849-2856.
Interpretive Summary: Manganese is an essential nutrient that also can be toxic at very high intakes. Toxicity cause psychological and neurological problems such as inappropriate behavior and loss of coordination. Some recent reports have suggested that lower amounts of manganese may be toxic and some have even suggested that high-manganese foods cause learning and behavioral problems. To address this we fed healthy young women either the lowest or highest amounts of manganese that they would be likely to encounter through the diet. Multiple behavioral and psychological tests were administered to the subjects. Manganese did not have a significant effect on any of the tests. Measures of manganese absorption and retention demonstrated that the body absorbed less manganese and eliminated manganese faster when it was present in the diet in high concentrations. Overall this study demonstrates that within the range of dietary concentrations a healthy adult would encounter, manganese is carefully controlled. As a result there appears to be relatively little risk of manganese toxicity from the diet.
Technical Abstract: Because manganese (Mn) is potentially toxic, and because dietary fat type may affect Mn absorption, the objectives of the current study were to determine whether diets containing very low or very high amounts of Mn and enriched in either saturated or unsaturated fats affected measures of neuropsychological and basic metabolic function. Healthy young women were fed for 8 wk each, in a crossover design, diets that provided 0.8 or 20 mg of Mn/d. One half of the subjects received 15% of energy as cocoa butter, and one half received 15% of energy as corn oil. A meal containing 54Mn was fed after 4 wk, and subjects underwent whole-body counting for the next 21 d. Blood draws and neuropsychological tests were administered at regular intervals during the dietary periods. When subjects consumed the diets low in Mn, compared with the high Mn diets, they absorbed a significantly higher percentage of 54Mn, but had a significantly longer biological half-life of the absorbed 54Mn. Manganese intake did not affect any neurological measures and only minimally affected psychologic variables. These data show that efficient mechanisms operate to maintain Mn homeostasis over the range of intakes that may be encountered in a mixed Western diet. Thus, dietary intakes of Mn from 0.8 to 20 mg for 8 wk likely do not result in Mn deficiency or toxicity signs in healthy adults.