Eating peppers twice a week could help reduce the risk of developing Parkinson's disease by up to a third.
Scientists found individuals who ate foods containing an edible form of nicotine, which also includes tomatoes, potatoes and aubergines, gained a degree of protection against the condition.
The research adds to evidence linking a reduced risk of the disease with smoking and the use of nicotine patches.
But experts urged caution, saying other constituents in the produce may have played a role in the findings, while the disease itself may also influence whether people smoke or eat certain foods.
'Our study is the first to investigate dietary nicotine and risk of developing Parkinson's disease,' said Dr Susan Searles Nielsen from the University of Washington in Seattle.
'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.'
For the new study, published in the journal Annals of Neurology, 490 patients newly diagnosed with Parkinson's disease, were questioned about their dietary habits and tobacco use.
A further 644 individuals not suffering from any neurological conditions also participated in the study.
Vegetable consumption in general was not found to affect Parkinson's risk.
But the likelihood of being diagnosed with Parkinson's reduced the more people ate vegetables from the Solanaceae family, which contain tiny amounts of nicotine, the addictive chemical in cigarettes.
The trend was strongest for peppers, mainly in people with little or no previous exposure to tobacco, with participants who ate them at least twice a week found to be 30 per cent less likely to develop Parkinson's.
Although the evidence suggests nicotine to be the active ingredient, the team did not rule out another chemical shared by tobacco and its cousins being responsible for the effect. One possibility was anatabine, which had anti-inflammatory properties.
Previous experiments in animals, showed stimulation of nicotine-sensitive receptor molecules in the brain prevents the kind of nerve damage seen in Parkinson's.
Human population studies have also found those who smoke are less likely to develop the disease.
Even passive smoking, which involves much less exposure to nicotine, seems to be protective.
Parkinson's is a progressive condition in which damage to brain cells eventually leads to tremors, rigidity and slow movement, and there is currently no cure.
Most people with the condition are aged 50 or over, and it affects about 127,000 people in Britain.
Claire Bale, from the charity Parkinson's UK, said the study was too small to draw any concrete conclusions.
She said: 'This was a small study which involved just over 1,000 people and to produce convincing results, these types of studies really need to involve much larger numbers - tens to hundreds of thousands.
‘It also studied a relatively young group of people, the average age was mid-60s, when Parkinson's is a condition which often develops much later in life.
'At the moment we don't fully understand the causes of Parkinson's and we don't know of anything which can prevent the condition, although there are a number of factors that may slightly lower risk including smoking cigarettes, drinking coffee and exercise.'
Dietician Catherine Collins, from St George's Hospital NHS Trust in London, said the study provided further evidence of the benefits of a Mediterranean-style diet rich in vegetables such as tomatoes and peppers.
But she said the findings had 'insufficient robustness' to justify promoting peppers as a protection against Parkinson's.
Nicotine content can vary in vegetables due to growing conditions, storage, and harvesting and cooking methods.