Caffeine is a stimulant substance that achieves its effects by making changes in your central nervous system, which includes your brain and spinal cord. While consumption of caffeine can negatively impact your health, it does not physically damage your brain. In fact, a 2010 study indicates that caffeine consumption may protect the brain from certain sorts of dangerous inflammation.
Background
Caffeine is an odorless, bitter substance that belongs a group of chemicals called xanthines. Common sources of this chemical include tea leaves, coffee beans, kola nuts and cacao pods, as well as the products derived from these plant components. In your brain, caffeine achieves its effects by interfering with the effects of a natural xanthine called adenosine, which acts as a neurotransmitter and relays messages between your nerves. Under normal circumstances, adenosine appears to build up in your brain when you're awake and helps initiate your sleep cycle when it reaches a certain concentration.
Harmful Effects
If you consume more than 500 mg to 600 mg of caffeine a day, which exceeds the amount typically found in four cups of coffee, you can develop a number of disruptive side effects, MayoClinic.com reports. These include a rapid heartbeat, insomnia, an upset stomach, muscle tremors, irritability, restlessness and nervousness. Excessive caffeine consumption can also elevate your blood levels of the stress hormone cortisol and lead to the temporary development of hallucinations or other effects associated with psychosis-like episodes. In addition, caffeine consumption can increase your urine output and lower your sensitivity to the glucose control hormone called insulin. However, it is not indicated as a source of brain damage.
Reduced Brain Inflammation
The neurotransmitter adenosine is known to play a role in the development of brain inflammation, according to the authors of a study published in 2010 in "Neuroscience Letters." Over a lifetime, this inflammation can potentially lead to onset of both Parkinson's disease and Alzheimer's disease. Caffeine is a recognized disruptor of adenosine. In a laboratory setting, the study authors gave varying doses of caffeine to rats for periods of two to four weeks. These doses reduced brain inflammation levels in older rats with age-related inflammation, as well as in younger rats with artificially-induced inflammation.
Considerations
People who consume 200 mg to 300 mg of caffeine per day, which is roughly equivalent to two to four cups of coffee, typically experience no adverse side effects, MayoClinic.com notes. However, some people are unusually sensitive to caffeine and may experience side effects at these relatively low dosages. When you take caffeine, it begins to affect your body in roughly 15 minutes and gets eliminated gradually over the course of a day. Studies performed on animals do not necessarily reflect potential results in human populations. Consult your doctor for more information on caffeine's effects and common levels of caffeine consumption.
References
- University of Washington: Caffeine
- MayoClinic.com: Caffeine; How Much Is Too Much? (Page 1); March 9, 2011
- Drugs.com: Caffeine Side Effects
- "Psychosomatic Medicine": Caffeine Stimulation of Cortisol Secretion...; Lovallo, Whitsett, et al.; 2005
- Refdoc.fr: Caffeine, Stress and Proneness to Psychosis-Like Experiences; Simon R. Jones, Charles Fernyhough; 2009
- "Neuroscience Letters": Caffeine Attenuates Lipopolysaccharide-Induced Neuroinflammation; Brothers, Marchalant, et al.; August 16, 2010
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