Nicotine present in tobacco has been used for its medicinal value for quite some time for diseases like Parkinson's disease and ulcerative colitis. A study by University of Miami School of Medicine, USA, now has shown that people from families prone to Parkinson's disease are less likely to develop the disease if they drink coffee on a regular basis.
Both coffee and nicotine have a link with dopamine in the brain. Dopamine is a chemical that decreases in patients with Parkinson’s disease. It is possible people who are going to have Parkinson's disease have lower levels of dopamine. Those with low levels of dopamine may be more likely to enjoy caffeine.