91探花researchers have found that the risk of someone getting Parkinson鈥檚 disease after high consumption of both iron and manganese together is greater than expected. Researchers say further studies may shed light on the apparent connection, and they say people should not change their diet on the basis of this study alone.
Other studies have shown that a diet high in iron increases the risk for Parkinson鈥檚 disease; the 91探花study reinforces those findings by demonstrating people in the top 25 percent of iron consumption were 1.7 times more likely to develop Parkinson鈥檚 disease than those in the lowest 25 percent.
鈥淲hat is new about our finding is that the risk for Parkinson鈥檚 disease from both iron and manganese together is greater than the risks for each of these two nutrients alone,鈥� said Dr. Karen Powers, a co-author of the paper and a research scientist in the Department of Environmental and Occupational Health Sciences in the 91探花School of Public Health and Community Medicine.
People who have diets high in both manganese and iron are 1.9 times more likely to be Parkinson鈥檚 patients than those who had lower levels of these two nutrients, according to the study. People who have diets high in iron and take one or more multivitamins a day are 2.1 times more likely to develop Parkinson鈥檚 disease.
The paper appears in the June 10 issue of Neurology, the journal of the American Academy of Neurology.
Iron and manganese are essential nutrients, and are important in the diet. Powers stressed that researchers are not suggesting that people change their diets on the basis of this study, but they should follow the labeled directions on dietary supplements.
鈥淭he benefits of eating foods rich in iron and manganese outweigh the risks of Parkinson鈥檚 disease. Foods rich in iron and manganese include spinach, lima beans, peas, wheat bread, peanuts, and other nuts and seeds. Vitamins are also a good supplement to a healthy diet 鈥� but 鈥榤ore is better鈥� is not true with all nutrients,鈥� Powers said.
鈥淲e had people in this study taking more than one multivitamin a day. That鈥檚 not a good idea, regardless. If the directions say 鈥榯ake one vitamin a day,鈥� that really means, 鈥榯ake one vitamin a day.鈥� This is also true for iron supplements.鈥�
She stressed that there is no 鈥渆asy answer,鈥� or solution, to the question of what causes Parkinson鈥檚. Parkinson鈥檚 disease is a complex disorder that has numerous environmental, lifestyle, and genetic factors that determine who will develop the disease.
The research was supported by grants from the National Institute of Environmental Health Sciences. Other authors of the paper include Drs. Harvey Checkoway and Gary Franklin, and Terri Smith-Weller; occupational health nurse, all of the Department of Environmental and Occupational Health Sciences, and Drs. W. T. Longstreth Jr. and Phillip D. Swanson, professors of neurology in the 91探花School of Medicine.