Eating vegetables that naturally contain nicotine, such as peppers and tomatoes, may reduce your risk of Parkinson's disease, according to a new study.
Previous research has found that smoking and other types of tobacco use are associated with a lower risk of developing Parkinson's disease, and it is believed that nicotine provides the protective effect. Tobacco belongs to a plant family called Solanaceae and some plants in this family are edible sources of nicotine.
This new study included nearly 500 people who were newly diagnosed with Parkinson's and another 650 unrelated people who did not have the neurological disorder, which is typically marked by tremors and other movement problems. The study participants provided information about their tobacco use and diets.
In general, vegetable consumption had no effect on Parkinson's risk. The more vegetables from the Solanaceae plant family that people ate, however, the lower their risk of Parkinson's disease. This association was strongest for peppers, according to the study, which was published May 9 in the journal Annals of Neurology.
The apparent protection offered by Solanaceae vegetables occurred mainly in people with little or no prior use of tobacco, which contains much more nicotine than the foods included in the study.
"Our study is the first to investigate dietary nicotine and risk of developing Parkinson's disease," Dr. Susan Searles Nielsen, of the University of Washington in Seattle, said in a journal news release. "Similar to the many studies that indicate tobacco use might reduce risk of Parkinson's, our findings also suggest a protective effect from nicotine, or perhaps a similar but less toxic chemical in peppers and tobacco."
Nielsen and her colleagues recommended further studies to confirm and extend their findings, which could lead to ways to prevent Parkinson's disease.
Although the study found an association between consumption of certain nicotine-containing foods and lower risk of Parkinson's, it could not prove a cause-and-effect relationship.
Still, one Parkinson's expert called the study "intriguing."
"It provides further evidence of how diet can influence our susceptibility to neurological disease -- specifically Parkinson's disease," said Dr. Kelly Changizi, co-director of the Center for Neuromodulation at the Mount Sinai Parkinson and Movement Disorders Center in New York City. "Patients often ask what role nutrition plays in their disease, so it's very interesting that nicotine in vegetables such as peppers may be neuroprotective."
Another expert said more research into the role of nicotine in Parkinson's disease is already underway.
"The observation that cigarette smokers have a reduced risk for Parkinson's disease has long been known, and has raised the idea that nicotine may reduce the risk for [the illness]," said Dr. Andrew Feigin, who is investigating the illness at the Feinstein Institute for Medical Research in Manhasset, N.Y.
"A nicotine skin patch is currently being tested in patients with early Parkinson's disease," he said.
The illness occurs due to a loss of brain cells that produce a chemical messenger called dopamine. The symptoms of the disease include loss of balance, slower movement and tremors and stiffness in the face and limbs. There is currently no cure for the disorder. Nearly 1 million Americans -- and 10 million people worldwide -- have Parkinson's, according to the Parkinson's Disease Foundation.