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Eating Peppers May Lower Parkinsonís Risk
- Jul 08 2013
Eating peppers two to four times per week is associated with lower risk of Parkinson’s disease (PD) by more than 20 percent, according to a new study published online May 9 in the Annals of Neurology. The relatively high level of nicotine in peppers may underlie the vegetable’s possible protective effect.
Scientists have known for years that people who smoke cigarettes or use other tobacco products are less likely to develop PD, but they have not understood why. Some scientists suspect nicotine as the possible protective agent. Researchers led by Susan Searles Nielsen, Ph.D., at the University of Washington wondered whether vegetables which contain small amounts of nicotine – those in the Solanaceae family that includes peppers, tomatoes, potatoes and eggplant – could also protect against PD but without the harmful effects of tobacco use.
The researchers used a questionnaire to ask 490 people with newly diagnosed PD and 644 people without PD how often they consumed peppers, tomatoes, tomato juice and potatoes (mashed or baked) during adulthood. The questionnaire also asked about history of tobacco use and consumption of vegetables not in the Solanaceae family.
- People who consumed any of the vegetables in the Solanaceae family once per day had a 20 percent reduced risk of PD, compared with people who ate all other vegetables daily, such as lettuce, carrots and cucumbers.
- Peppers, which have the highest level of nicotine among the studied vegetables, had the largest protective effect. People who ate green, yellow, or red peppers two to four times per week had a 30 percent reduced PD risk, and those who ate peppers daily had a 50 percent reduced risk of developing PD.
- The protective effect of vegetables in the Solanaceae family was highest for people who never used tobacco. For example, people who never used tobacco and ate peppers daily had an 87 percent reduced risk of PD, compared with a 12 percent reduced risk for tobacco users who ate peppers daily.
What Does It Mean?
People with Parkinson’s disease and their loved ones are often curious about recommended diets for PD. The only compelling data have shown that eating a Mediterranean diet, which is recommended to prevent other medical conditions such as strokes and heart attacks, may be linked to lower risk for PD. All specific vitamins studied to date have failed to show any benefit in slowing down or preventing PD (including co enzyme Q10, vitamins C, E and others).
In contrast, studies have shown that tobacco use is linked to lower PD risk, yet tobacco cannot be used as a treatment for PD both because of its many harmful risks and because scientists do not yet know which compound within tobacco is protective. However, this study shows that eating vegetables in the Solanaceae family, in particular peppers, which contain nicotine, should be explored further for PD.
Previously, scientists had shown that in animal models, nicotine was able to protect dopaminergic neurons, the brain cells lost in PD, in animal models of the disease. But they were not sure whether the tiny amounts of nicotine in vegetables of the Solanaceae family would be enough to protect against PD.
In this study, tomatoes showed a hint of a protective effect, but peppers, which contain more than twice as much nicotine as tomatoes, were most strongly associated with a decreased PD risk. The fact that tobacco users see a much smaller protective effect of vegetables probably reflects that smokers already receive a very high dose of nicotine, much higher than they could get from dietary sources.
It’s important to note that the researchers still aren’t certain that it is the nicotine in peppers and tobacco, and not some other chemical that lowers PD risk. And while the study is interesting, it has several weaknesses. Like other epidemiological studies, it identifies an association rather than a cause and effect. Therefore, doctors are still a long way off from recommending that people eat peppers to prevent PD. Importantly, these results need to be confirmed in other studies. But in the meantime, increasing one’s daily intake of vegetables like peppers and tomatoes, in moderation, as part of a Mediterranean-style diet is one way to help optimize health for the better.
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Reference: Nielsen SS, Franklin GM, Longstreth WT, Swanson PD, Checkoway H (2013) Nicotine from edible Solanaceae and risk of Parkinson disease. Ann Neurol. DOI: 10.1002/ana.23884 http://dx.doi.org/10.1002/ana.23884
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Source Date: Jul 08 2013