Although the exact cause of Parkinson's disease is unknown, genetic factors and exposure to toxins may play a role in this degenerative neurological disorder, according to MayoClinic.com. Excessive amounts of the mineral manganese cause changes in cognitive status and motor function that resemble the symptoms of Parkinson's. However, research has not confirmed that high levels of manganese increase your risk of developing Parkinson's disease.
Significance
Parkinson's disease is a neurological disorder that causes progressive loss of muscular control. In a healthy brain, neurons produce a chemical called dopamine, which transmits signals to your nerves to coordinate muscle movement. In Parkinson's disease, the neurons that produce dopamine stop functioning properly or die. Manganese, an essential mineral that's toxic at elevated levels, causes symptoms that are similar to Parkinson's. However, recent research suggests that manganese toxicity does not affect dopamine production in the same way that Parkinson's does.
Neurotoxicity
Your body needs dietary manganese for metabolism, bone development and wound healing. Manganese is abundant in vegetables, fruits and nuts, but you are not likely to consume the mineral in toxic amounts through a balanced diet, says the Linus Pauling Institute. However, people with liver disease, newborns and children, and people with iron deficiencies are more likely to accumulate manganese at harmful levels. Because inhaled manganese directly affects the brain, the risk of neurotoxicity increases in people who are exposed to the chemical through industrial emissions or occupational situations. Manganese toxicity, or manganism, can cause Parkinson's-like symptoms, such as tremor, difficulty walking, alterations in balance and a mask-like face.
Research
Scientists first described manganese toxicity in humans in 1837, when they observed a loss of motor control in industrial workers who were exposed to manganese powder. Recent research indicates that people who live near steel factories or in other areas with high levels of manganese emissions have a higher rate of Parkinson's disease. A high intake of dietary manganese combined with a high intake of dietary iron has also been linked to an increased incidence of Parkinson's disease. However, according to a 2010 study by Tomas R. Guilarte, Ph.D., published in "Environmental Health Perspectives," clinical evidence indicates that manganese toxicity does not damage dopamine-producing neurons in the same way that Parkinson's does.
Treatment
Levodopa, a medication that the brain converts to dopamine, is one of the most successful treatments for the symptoms of Parkinson's disease. However, levodopa does not improve the symptoms of manganism, according to Guilarte. The differences between manganism and Parkinson's disease call for different clinical approaches and treatment, says Guilarte.
Recommendations
The adequate intake for manganese, or the amount you need to stay healthy, is 2.3 mg per day for men and 1.8 mg for women. The tolerable upper intake level, or the most you can ingest each day without adverse effects, is 11 mg per day for all adults. The Linus Pauling Institute recommends that adults over 50 should not take more than 2 mg of manganese per day in supplement form. However, manganese toxicity through supplements is very rare, and toxicity through food has never been reported, according to the Linus Pauling Institute.
References
- MayoClinic.com: Parkinson's Disease
- Linus Pauling Institute at Oregon State University: Micronutrient Information Center: Manganese
- PubMed: Parkinson's Risk Associated with Dietary Iron, Manganese and Other Nutrient Intakes
- PubMed: Environmental Health Perspectives: Manganese and Parkinson's Disease: A Critical Review and New Findings; Tomas R. Guilarte, August 2010
- PubMed: Metal Emissions and Urban Incident Parkinson's Disease: A Community Health Study of Medicare Beneficiaries by Using Geographic Information Systems
