Nicotine in Peppers Decreases Parkinson’s Disease Risk

by | Aug 15, 2016 | 2013, Brain Health, Fruits and Vegetables, Parkinson's

Written by Joyce Smith, BS. This study concluded that eating peppers, which are high in nicotine content, 2-4 times per week lowered the risk of developing Parkinson’s Disease by approximately 30%.

peppersStudies have shown that nicotine is neuroprotective 1 and that cigarette smoking along with other uses of tobacco, 2 and possibly even exposure to environmental tobacco smoke, 3 may reduce the risk of Parkinson’s disease (PD). However, Neilsen et al caution “Nonetheless, it remains unresolved whether nicotine or other constituents of tobacco smoke are truly protective, or rather, that failure to smoke indicates preclinical behavioral differences in persons predisposed to develop PD.” 

There are many edible plants such as peppers, tomatoes, potatoes and eggplants that all contain nicotine 4, and, although the nicotine absorbed from these plants is negligible compared to the amount absorbed from active smoking and environmental smoke, 5 even small amounts of nicotine can saturate portions of the nicotine receptors in our brains. 6 Studies in animal models of PD have shown that stimulating nicotine receptors in the brains of these animals with induced PD actually protects the brain cells (called neurons) that produce dopamine. 7 It is the decreased dopamine production that leads to the muscle tremors, slowness of movement, impaired balance, and a shuffling walk that characterize this disease.

The objective of this study was to determine whether the consumption of foods from the Solanaceae family that contain naturally occurring nicotine, such as peppers, tomatoes and potatoes, could reduce the risk of Parkinson’s disease.

For this population-based case-control study, researchers recruited 490 patients with newly-diagnosed idiopathic Parkinson’s disease (PD) and 644 unrelated healthy individuals with no neurological disorders for the control group. Both groups were given a typical frequency of food consumption questionnaire involving 71 foods and beverages consumed during adulthood. The questionnaire covered all major food groups and caffeine sources. Researchers made adjustments for consumption of other vegetables, age, sex, race/ethnicity, tobacco use, and caffeine intake.

Results:

  • Not all foods offered the same degree of protection. When consumption of all vegetables was combined, there was no association with PD risk (Ptrend = 0.95)
  • Researchers found a strong inverse association for peppers (Ptrend=0.005). In fact, eating 2-4 peppers per week lowered the risk for developing PD by approximately 30%. In addition, this potentially protective effect of eating peppers occurred in men and women who were non- tobacco users or who had smoked cigarettes for less than 10 years.

Limitations of this study:

A strong feature of this study was that researchers used newly diagnosed cases of PD and a highly comparable control group that was unrelated to PD patients by blood or marriage. However, there were also limitations such as the use of self-reported food questionnaires that assessed diet intake only through adulthood. Heartburn, constipation, and “difficulty swallowing” may also have affected the diet choices of the PD patients, yet these questions were not addressed. Additional limiting factors were the lack of data for environmental tobacco smoke exposure and the absence of data on diet for different periods of the PD patients’ lives.

Conclusion:

Researchers believe that epidemiological studies should be done to address these limitations. Before any exploration of dietary or pharmaceutical interventions for the prevention of Parkinson’s disease can occur, further research is needed to confirm the associations between diet and PD that were made in this study.

Source: Nielsen, Susan Searles, Gary M. Franklin, W. T. Longstreth, Phillip D. Swanson, and Harvey Checkoway. “Nicotine from edible Solanaceae and risk of Parkinson disease.” Annals of neurology 74, no. 3 (2013): 472-477.

© 2013 American Neurological Association

 Posted August 15, 2016.

References:

  1. Quik M, Perez XA, Bordia T. Nicotine as a potential neuroprotective agent for Parkinson’s disease. Movement disorders. 2012;27(8):947-957.
  2. Wirdefeldt K, Adami H-O, Cole P, Trichopoulos D, Mandel J. Epidemiology and etiology of Parkinson’s disease: a review of the evidence. European journal of epidemiology. 2011;26(1):1-58.
  3. Searles Nielsen S, Gallagher LG, Lundin JI, et al. Environmental tobacco smoke and Parkinson’s disease. Movement Disorders. 2012;27(2):293-297.
  4. Siegmund B, Leitner E, Pfannhauser W. Determination of the nicotine content of various edible nightshades (Solanaceae) and their products and estimation of the associated dietary nicotine intake. Journal of agricultural and food chemistry. 1999;47(8):3113-3120.
  5. Andersson C. Nicotine alkaloids in Solanaceous food plants. Nordic Council of Ministers; 2003.
  6. Brody AL, Mandelkern MA, London ED, et al. Cigarette smoking saturates brain α4β2 nicotinic acetylcholine receptors. Archives of general psychiatry. 2006;63(8):907-914.
  7. Takeuchi H, Yanagida T, Inden M, et al. Nicotinic receptor stimulation protects nigral dopaminergic neurons in rotenone‐induced Parkinson’s disease models. Journal of neuroscience research. 2009;87(2):576-585.