Caffeine, or 1,3,7-trimethylxanthine, is the most consumed psychoactive substance in the world and completely unregulated. In the United States, it is consumed by an estimated 90 percent of Americans every day, usually within coffee, tea and soft drinks, but also via chocolate, herbal supplements and prescription drugs. Caffeine consumption leads to physical dependence and withdrawal symptoms, including insomnia, or the inability to fall asleep.
Biochemistry of Caffeine
Once caffeine is absorbed, it quickly passes through the blood-brain barrier and affects brain chemicals. Specifically, it interferes with the action of adenosine, a naturally occurring neurotransmitter. The actions of adenosine include suppressing neural activity, dilation of blood vessels, which increase blood flow, and stimulating cellular metabolism. Thus, the effects of caffeine consumption are increased brain activity, which is perceived as a temporary increase in alertness and thought processing, and reduced drowsiness and fatigue, as cited in the book "Biochemical, Physiological and Molecular Aspects of Human Nutrition." Caffeine does not increase energy metabolism in the body; instead, long-term consumption fatigues the adrenal glands and reduces energy metabolism.
Caffeine Addiction
Caffeine has fairly strong addictive properties that can lead to physical dependence, although the amounts needed and the time required vary dramatically from person to person. Coffee, tea and soft drink consumption is encouraged in many countries, so habituation is common. The half-life of caffeine within the body is typically between five and six hours, which, in those addicted to it, causes symptoms of withdrawal to surface within 12 to 24 hours after last intake.
Caffeine and Insomnia
Insomnia is the inability to fall asleep and can often be caused by consuming caffeine within six hours of going to bed because of the increase in brain activity. However, somewhat paradoxically, insomnia is also a symptom of caffeine withdrawal because of the rebounding effects of adenosine. Without caffeine, the brain temporarily overproduces adenosine, which causes over-dilation of blood vessels and hypotension. These effects often cause migraine-like pounding headaches, which often contribute to sleeplessness. Other symptoms of caffeine withdrawal that could lead to insomnia include increased heart rate, increased thirst and hunger, heightened anxiety and nervousness, mild depression, muscle pain or stiffness, and anal sphincter relaxation, as cited in the book "Human Biochemistry and Disease." Withdrawal symptoms typically last less than a week and can be mitigated by drinking plenty of water.
Caffeine Sources
In addition to coffee beans and tea leaves, other natural sources of caffeine include kola nuts, guarana berries and cacao pods, which are made into cocoa powder and chocolate. Black and green teas contain caffeine, although herbal teas do not. Some painkillers contain caffeine also. The only way to relieve insomnia induced by caffeine withdrawal is avoiding all sources of caffeine for at least a week. According to the book "Medical Herbalism: The Science Principles and Practices of Herbal Medicine," melatonin, valerian root, chamomile and magnesium supplements can all help induce sleep in those suffering from insomnia.
References
- "Contemporary Nutrition"; Gordon M. Wardlaw; 2010
- "Biochemical, Physiological and Molecular Aspects of Human Nutrition"; Martha Stipanuk; 2006
- "Biochemistry of Human Nutrition"; George Gropper; 2000
- "Human Biochemistry and Disease"; Gerald Litwack; 2008
- "Medical Herbalism: The Science Principles and Practices of Herbal Medicine"; David Hoffmann; 2003
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