Caffeine is a chemical in many foods and beverages, including coffee, tea, chocolate, guarana and kombucha. It is widely used in the Western world as a stimulant because it can help increase alertness, improve mental focus and keep you awake. Unfortunately, caffeine also has a negative effects. In addition to disrupting sleep, it also has detrimental effects on several internal organs.
Caffeine has several negative effects on the heart, according to the Harvard Medical School website. Excessive caffeine consumption can cause arrhythmia, or irregular heartbeat. It can also increase the heart rate, although this effect typically subsides as your body processes and eliminates the caffeine from your system. Most important, caffeine can contribute to hypertension, or high blood pressure. Hypertension puts you at risk for heart disease and strokes, notes the University of Maryland Medical Center. It can also produce effects such as headaches, nausea, eyesight problems and seizures.
Recent studies suggest that moderate coffee consumption might help offset the effects of alcohol on the liver, according to the Medical News Today website. However, the caffeine present in coffee also negatively affects the liver. According to Dr. Donna Smith, contributor to the Chet Day website, caffeine combines with hydrochloric acid in the stomach to produce a toxin called caffeine hydrochloride. This toxin is absorbed by the liver, which must neutralize and flush it out of your system. As the liver processes toxins, it incurs tissue damage and forms scar tissue, which eventually impacts the liver's ability to function correctly.
Ingesting foods and beverages containing caffeine can affect the brain by affecting the secretion of chemicals in the brain that affect the body. The brain reacts to caffeine by producing adrenaline, which can have short-term effects of increased alertness and energy, but produces a "crash" after the caffeine wears off, according to the Pacific Northwest Foundation. It also interferes with the brain's production of adenosine, a chemical that induces calmness. Coffee and other caffeine-containing products cause the brain to release cortisol, a stress hormone that constricts blood vessels, contributes to hypertension and hampers the absorption of essential minerals and vitamins, among other negative effects.