Regular doses of caffeine have been shown to reduce the risk of Parkinson’s disease in both men and women, unless those women also happen to be pre-menopausal, undergoing hormone replacement therapy and drinking more than five cups of coffee a day. In these women, possibly because of an interaction with the estrogen in hormone therapy, caffeine appears to lead to an increased risk of developing Parkinson’s disease. Women as a whole are 50% more likely to develop Parkinson’s disease, however.
Symptoms of Parkinson’s
Parkinson’s is a chronic, degenerative disease of the central nervous system. Though its most well-known symptom is a tremor in the extremities, those suffering from it will often exhibit a number of other symptoms, including a slow, shuffling walk, short term memory loss, fatigue and depression. While rare in those under 60, it can strike at any age. A genetic agent has been blamed for some instances of Parkinson’s, and a severe injury to the head appears to increase your risk, as does a history of exposure to environmental toxins, but most cases have no obvious cause.
Physiology of Parkinson’s
Parkinson’s occurs when dopamine-producing nerve cells (neurons) in an area of the brain known as the substantia nigra die or otherwise become impaired. Your brain uses dopamine for, among other things, relaying signals between its different regions. Normally, whenever there’s a need for a smooth, purposeful, movement – things like reaching for a cup of tea, or pushing your hair back behind one ear – the substantia nigra sends a signal to another part of the brain called the corpus striatum. However, in a Parkinson’s sufferer, the lack of dopamine in the substantia nigra leads the nerve cells in that area to fire erratically, producing the disease’s characteristic tremor. Since dopamine is also used by the brain for activities as diverse as concentration, mood, sleep and cognition, Parkinson’s disease will lead to noticeable changes in those brain functions as well.
Caffeine and Parkinson’s
Caffeine has been shown to affect dopamine levels in the brain by blocking the chemical process that destroys the dopamine-producing neurons of the substantia nigra. Since Parkinson’s symptoms do not appear until 80 to 90 percent of the dopamine producing neurons are dead, anything that slows their destruction has a significant impact on the progress of the disease. Oddly enough, nicotine has the same effect. Smokers develop Parkinson’s disease at a rate much lower than that of the general population – not that anyone is suggesting taking up smoking as a Parkinson’s preventative.
What’s not known at present is the amount of caffeine needed to produce the neuron-protecting effect, nor how much caffeine is too much. There’s no reason to alter your daily coffee intake out of the fear of Parkinson’s. If you don’t care for coffee, try black or green tea, both of which are good caffeine sources. All three are rich in antioxidants, which will help keep your brain and body in healthy shape for a long time.