Iron-rich diet may raise risk of Parkinson's

June 11, 2003 in Nutrition Topics in the News, Vitamins, Minerals, Supplements

Iron-rich diet may raise risk of Parkinson's

High levels of dietary iron and manganese may raise the risk of Parkinson's disease, a new study shows.

People who consumed high levels of iron and manganese were almost twice as likely to develop the disease as those with a diet that contained lower levels of the two minerals. Sometimes people end up with overly high levels of vitamins and minerals because they overdo multivitamin supplements, said the study's lead author from the School of Public Health at the University of Washington in Seattle.

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. Iron and manganese are (each) known to be a neurotoxin in high amounts. When both are high, the effect is more than it would be if you just added the two together.

For the new study, researchers compared 250 people who had been newly diagnosed with Parkinson's disease to 388 similar people who did not have the disease. All 638 people were asked about the foods they ate and the supplements they consumed.

Those who had the highest levels of dietary iron were 1.7 times more likely to have developed Parkinson's than people who consumed the least iron, the researchers report in the journal Neurology. People who consumed higher than normal levels or iron and manganese were 1.9 times as likely to have developed 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.

People shouldn't try to eliminate the two minerals from their diets because of the new results, the researchers said. "We need iron and manganese," they said. "But many people think if a little bit of something is good, then a lot if better."

Iron and manganese both can contribute to oxidative stress, which results when toxic substances called free radicals are released as part of energy consumption and metabolism. In people with Parkinson's, cells that make a brain chemical called dopamine degenerate over time.

Some 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.

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