Neurological Effects Of Caffeine

Caffeine consumption

41 cases of caffeine intoxication were reported in the United States from 2002 to 2004. This fact could indicate an increase in caffeine dependence as well as withdrawal symptoms. A moderate amount of caffeine intake, which is around 300mg or the equivalent of 4 cups of coffee per day, is regarded as a safe amount of caffeine to be consumed.

Biochemical characteristics

Caffeine is readily absorbed by the gastrointestinal tract of the human body and up to 99% of the chemical is absorbed within 45 minutes. Caffeine penetrates through biological membranes such as the blood-brain barrier (BBB) and the placenta, which is why it causes neurological affects as well as affecting a fetus. Caffeine does not accumulate in tissues or organs.

Effects of caffeine on the body

Caffeine can affect many other systems of the body and they include the following:

• Cardiovascular system - caffeine can cause arterial wall stiffness as well as vasodilatation which results in an increased blood pressure. It should therefore be consumed with caution in people who are hypertensive and who are experiencing high stress levels. 
• Respiratory system - the respiratory rate is increased here.
• Gastrointestinal system - the small intestine becomes stimulated which results in the release of water and sodium from this organ. Caffeine can also lead to an upset stomach and result in symptoms such as abdominal cramps, nausea and vomiting.
• Urinary system - increased urinary frequency occurs due to the release of water from the gastrointestinal tract.
• Endocrine system - caffeine stimulates the release of catecholamines which results in an increase in the basal metabolic rate. This process includes lipolysis which releases free fatty acids.

READ Is Decaffeinated Or Decaf Coffee Healthy?

Interactions with certain medications or supplements

It's very important to take note of interactions that caffeine may have with certain medications. Some of the more important interactions include the following:

• Antibiotics - Ciprofloxacin and norfloxacin can interfere with the breakdown of caffeine which can result in an increased length of time of caffeine in the body. This can then lead to unwanted effects of caffeine.
• Theophylline - taking this medication with caffeine containing products can increase the effect of theophylline. This can then result in symptoms such as nausea, vomiting and heart palpitations.
• Echinacea - this is a natural supplement used to prevent infections such as the common cold. This supplement can increase the concentration of caffeine when taken together, and can then increase the effects of caffeine on the body.

The Neurological Effects Of Caffeine

Short-term benefits of caffeine

As mentioned, any benefits from caffeine consumption will be short lived but they can be experienced with moderate use of caffeine. That means that health disadvantages can be limited by not exceeding 300mg of caffeine intake per day.

Caffeine intake has been shown to aid in arousal due to interaction with certain neurotransmitters in the brain. Increased arousal leads to increased awareness and therefore a better ability to carry out or perform a task. It was also shown that caffeine intake can increase alertness and decrease fatigue levels when taken in moderate to large doses. This increase in alertness has also indicated the possible benefit to sleep deprived drivers' ability to perform driving tasks.

Caffeine intake has also shown to subjectively reduce stress levels, but this was also a very short lived experience since these users increased their caffeine intake to moderate and high doses.

Disadvantages of caffeine 

As mentioned, caffeine seems to increase alertness and reduce fatigue which is the main reason why it is consumed by those who need to perform tasks that need to be completed before a close deadline. The result here is that these people can start suffering from insomnia. 

Excessive or persistent intake of caffeine can lead to impaired cognition and, particularly, impairment in perceptual learning and memory. Even a moderate dose of caffeine can result in impaired motor skills.

One major issue of caffeine intake is that it was shown that high doses of caffeine exposure to developing brain tissue resulted in depressed hippocampal neurogenesis. This means that there was a disruption of neural circuits where adult-born neurons finally become integrated.

A single 300mg dose of caffeine can already cause an increase in tension and anxiety, whereas a 400mg dose increases anxiety when combined with a stressful task. Patients with anxiety related issues, such as panic disorders, were shown to be more prone to symptoms such as nervousness, anxiety, fear, tremors and palpitations when they were administered a low dose of caffeine as compared to patients with mood disorders such as depression.

Patients who consume more than 300mg of caffeine daily are more prone to experiencing auditory and/or visual hallucinations, as compared to those who only consume around 1-2 cups of coffee a day. These hallucinations can occur due to caffeine increasing the physiological effects of stress.

Caffeine can also lead to acute caffeine intoxication which is characterized symptoms of irritability, nervousness, anxiety, headaches, muscle twitching, palpitations and insomnia.

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Some caffeine users have given evidence of withdrawal symptoms caused by stopping caffeine intake, but these were reported to be mild to moderately bearable symptoms which resolved over a short period of time. Caffeine withdrawal symptoms have included anxiety, increased depression and fatigue.