• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Caffeine is a naturally occurring xanthine.

Extracts from this document...


Caffeine Caffeine has played a central role in many cultures. Coffee was first discovered over 1000 years ago, and approximately 75% of Americans drink coffee on a regular basis. Despite the thousand years that have passed, there is still controversy surrounding the biological effects of coffee and it's primary active ingredient, caffeine. Caffeine is the most widely used stimulant drug in the world, usually ingested in the form of coffee, tea, soft-drinks, and chocolate. (Honig) Caffeine is derived from a bean or from tea leaves and can be found in the seeds or fruits of more then 60 species worldwide.(American Academy) Caffeine has numerous effects and it is disputed whether caffeine is overall beneficial or harmful. Caffeine is a naturally occurring xanthine (precursor to uric acid often found in urine) used as a central nervous system (CNS) and respiratory stimulant, or as a mild diuretic. Other xanthine derivatives include the bronchodilator theophylline and theobromine, a compound found in cocoa and chocolate. Caffeine is a mild, but direct stimulant at all levels of the CNS that quickens the heart and cardiovascular system as well. ...read more.


Therefore, the signal to stop producing adenosine that would have been sent by the adenosine becomes blocked, which results in a surplus of adenosine and explains the stimulatory effects of caffeine. Decades of research and centuries of human consumption suggest the relative safety of caffeine. According to the National Library of Medicine, more than 19, 000 scientific studies to date have been conducted on caffeine, and the US Food and Drug Administration still considers caffeine to be "Generally Recognized as Safe." A study at the University of California showed that the average daily consumption of 200 mg as safe.(Ascherio) The study also concluded that the the lethal dose of caffeine is 192 mg/kg, meaning for the average american would need to drink more than 150 cups of coffee to reach lethal overdose!(Bobrow) Caffeine enhances performance on observational and simple tasks that require sustained response. These effects are in tired or bored subjects, although there is evidence that benefits may still occur when the person is unimpaired. (Smith) Caffeine also boosts the numbing effect of aspirin, and recent scientific research carried out at the Mayo clinic, Harvard School of Public Health, US Veterans Administration and other medical centers show that caffeine is not only safe but also beneficial. ...read more.


(Cherniske) Professor Jack James of the University of Ireland conducted studies that showed that long-term caffeine consumption contributes to adrenal insufficiency, and adversely affecting over 150 hormones . Meaning stress , blood pressure, blood sugar, mineral levels, immune activity, inflammation, cell growth and repair are all negatively affected. Other studies showed caffeine contributed to problems like: Gastritis, acid reflux, ulcers, irritable bowel syndrome, hypoglycemia, vitamin loss, PMS, fibrocystic breasts, premenopausal symptoms, decreased fertility, birth defects, asthma, fibromyalgia, chronic fatigue, autoimmune disease and rheumatoid arthritis.(James) Many studies have suggested a relationship between chronic caffeine use and a number of diseases. However, the cause-and-effect evidence is difficult to prove because of lifestyle variables among the subjects in the studies (eg. smoking, alcohol consumption, exercise), differences in genetic inheritance, form of caffeine intake (coffee, tea, sodas), and the presence of other biologically active substances in the beverage. (Brice) The consumption of caffeine does have side effects, some negative and some positive, but it is clear that when taken in moderation caffeine is never adverse to ones health. However, caffeine consumers should be aware of withdrawal and keep themselves up to date on the latest caffeine research. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Humans as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Humans as Organisms essays

  1. Marked by a teacher

    Is the MMR vaccination safe?

    5 star(s)

    however this happens in less that one child in a million who have the vaccination (8). Some parents feel that if there is any risk that there child will be affected by the vaccination they should not have it. Condition Children affected after the natural diseases Children affected by the

  2. Peer reviewed

    Abortion case study

    3 star(s)

    24-72 hours later the second pill is taken: It contains misoprotal. Misoprotal will make the pregnant woman's uterine muscle contract vigorously. The second pill is vital to the termination because it is the second pill which actually reduces the baby's survival chances to zero.

  1. Stem Cell Research

    Therefore the chances of rejection are much higher if embryonic stem cells are used in treatments. This is because the embryonic stem cells are going to have a different genome and will be covered in foreign antigens; thus the body will recognise them as foreign, increasing the chances of rejection from the body and complications after transplantation.

  2. The Biological and Psychological Impact of Smoking Cigarettes

    Aneurysms may eventually cause the affected artery to burst or clot, resulting in death or severe illness. Smokers are up to eight times more likely to die from a ruptured aneurysm of the abdominal aorta than non-smokers(6). More than 90% of people who suffer from an aortic aneurysm have smoked

  1. An investigation into how alcohol and caffeine affect the heart.

    The dilutions used in the experiment are recorded in the table below. Firstly, 10ml of 1% alcohol solution was taken and placed in a test tube. A single daphnia was taken and placed in the test tube with the 1% alcohol solution and left to acclimatise for five minutes.


    Also the tablet is more easily dissolved into the water by crushing it up. * Laboratory coat and disposable gloves will make sure that clothing and the hands are protected. * Goggles will ensure that the risk to the eye is reduced and they are protected from the caffeine.

  1. is the mmr vaccination safe?

    How does the MMR vaccination work and give immunity? (http://www.riversideonline.com/source/images/image_popup/id7_immunization.jpg) In a basic sense, vaccinations are a method of giving your body protection against a disease it may be exposed to in the future. Inside the vaccine is a number of smaller and purposefully weaker micro-organism that causes that disease.

  2. Are Vaccines safe?

    ?As with all new medicines, all vaccines are extensively tested for safety before they're made routinely available to the general public?[2] This quote is from the NHS website so you can assume that it is reliable, it tells you that the Medicines and Healthcare products Regulatory Agency (MHRA)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work