Diet and risk of Parkinsonism

High levels of dietary iron and manganese may increase the risk of Parkinson's disease, according to a new study. Parkinson's disease causes tremors, muscle rigidity and movement problems. The underlying cause is the slow loss of neurons that produce dopamine, which is an important brain chemical involved in movement. Treatment with levodopa, a precursor of dopamine that the brain can use to produce the brain chemical, can alleviate the symptoms. However, levodopa does not slow the progression of the disease.Researchers in the department of environmental and occupational health sciences in the School of Public Health at the University of Washington compared 250 people who had been newly diagnosed with Parkinson's disease to 388 similar people who did not have the disease. All the people in the study were asked about the foods and the supplements they ate.People who consumed high levels of iron and manganese were almost twice as likely to develop the disease compared to those with a diet containing lower levels of the two minerals. Iron and manganese are (both) known to be a neurotoxin in high amounts. In this study, iron levels were high in some cases because people were taking more than one multivitamin or a multivitamin and an iron supplement.

They found that those who had the highest levels of dietary iron were 1.7 times more likely to develop Parkinson's than people who consumed the least iron. People who consumed higher than normal levels of iron and manganese were 1.9 times as likely to develop Parkinson's as people with lower levels of the minerals in their diets. People who consumed above-average levels of iron and took at least one multivitamin or iron supplement each day were about twice as likely to develop Parkinson's than people with below-average iron consumption who did not usually take supplements.Iron and manganese both can contribute to oxidative stress. Oxidative stress results when toxic substances called free radicals are released as part of energy consumption and metabolism. It was noted that in people with Parkinson's, cells that make a brain chemical called dopamine degenerate over time. Generally a person who has Parkinson's has lost more than half of these cells. Researchers suspect that oxidative stress may be involved in the degeneration of the dopamine cells. And the fact that iron and manganese raise the risk of Parkinson's suggests that oxidative stress may, indeed, be part of the process. However people should not try to eliminate the two minerals from their diets because of these results. As we do need iron and manganese, but in limited amounts.

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