Coffee and its Effects on Humans

II. DISCUSSION:


      Caffeine has been studied extensively in both animals and humans. Research has established that any biological effects of caffeine in either animals or humans depend strongly on the dose, method of administration and duration of exposure.
      Human studies have included both direct biological tests, as well as epidemiological research examining data from surveys of human populations.
      Because such extensive human data are available on caffeine, experts advise careful evaluation of high-dose animal experiments before they are interpreted as immediately relevant to human safety.
      The blood distributes it throughout the body. It even manages to pass through the blood-brain barrier.
      The Caffeine is absorbed rapidly into the bloodstream from the gastro-intestinal tract. It reaches maximum concentration within about an one hour. half life of caffeine in the human body varies between 3 to 7 hours. Throughout the body it increases metabolic rate by around 10%. Females metabolise caffeine 20-30% more quickly than males. However, it will take women on "the pill" twice as long to metabolise caffeine as women who are ovulating.
      Early experiments showed that low concentrations of caffeine may produce small decreases in heart rate, whereas higher concentrations may make the heart beat abnormally fast.
      In the brain it constricts the cerebral blood vessels. If you're used to drinking several cups of coffee a day but then you quit, those blood vessels will dilate, maybe enough to give you a powerful headache. It's one of the best known withdrawal symptoms.
      Caffeine is a mild stimulant. People differ greatly in their innate sensitivity to caffeine. Whereas many individuals can drink several cups of coffee within an hour and notice no effects, others may feel some effect after one serving.
      Caffeine does not accumulate in the bloodstream or body and is normally excreted within several hours following consumption.
      In sensitive individuals, tests show that caffeine can quicken reaction time and prolong vigilance of various demanding tasks. Many people, such as shift workers and college students studying late at night, find caffeine-containing beverages can help them stay alert to finish their work.
      Although a widespread belief, caffeine-containing foods and beverages will not actually help "sober up" an individual who has consumed too much alcohol.
      It may manage to puncture that aura of numbness and make you feel a little sharper but it's no better at sobering you up and lowering your blood alcohol level than a glass of water.
On the other hand caffeine is a good friend the morning after. Alcohol can give you a thumping headache by enlarging cranial blood vessels. Caffeine constricts them and so may bring some relief from the hangover blues. That's why it's an ingredient in some over-the-counter pain killers.
      The effect of caffeine on sleep varies widely among the population. Individual sensitivity and frequency of consumption seem to determine which individuals feel some effect. Studies at Vanderbilt University have found many individuals feel no effects from caffeine on sleep, while others report delayed, reduced or poorer quality sleep.
      It can produce insomnia - delaying the onset of sleep and reducing total sleeping time. It has a small effect on respiration by increasing blood flow through the lungs and increasing the supply of air by relaxing bronchiolar and alveolar smooth muscle. That's why it's proving effective in treating the breathing problems of some prematurely born infants.
      Drinking decaffeinated coffee is, in theory, a way of enjoying the beverage while eliminating the caffeine and preserving the taste. While improvements have been made to the processes, the taste of caffeinated coffee is not preserved perfectly, rocess completely eliminates all of the caffeine.
      To understand decaffeination processes completely, one must consider the function of the caffeine molecule, with specific attention to taste. The caffeine molecule is a bitter alkaloid, so it contributes to acidity as well as the bitter properties of coffee. Removing this molecule will alter those taste factors. Other flavor compounds are also diminished or removed in the decaffeination process. This means that the taste of decaffeinated coffee is usually inferior to that of caffeinated coffee.
     "Decaffeinated" coffee can vary wildly. A product may contain anywhere between 2 and 13 milligrams of caffeine and still be labeled "decaffeinated". Several studies have shown that store bought decaf has a higher ratio of caffeine, so you probably want to purchase your decaffeinated coffee beans from a gourmet roaster.                       Furthermore, random samplings of brewed coffee suggest that - surprise - human error exists so that sometimes that cup of decaf is actually just regular coffee in an orange-handled pot. If you are extremely concerned about caffeine or sensitive to its effect, you should buy the beans from a reputable source and brew the coffee yourself.
      There are two types of decaffeination processes. The first is called the Swiss Water Process method. Decaf coffee made with this method can be found at most gourmet coffee shops, organic food grocery stores. The other decaffeination processes use some sort of a chemical solvent.
      In all of the decaffeination processes, the green coffee beans begin the journey by being steamed and/or soaked in water. This makes the caffeine soluble and primed for extraction.

The Swiss Water Process Method
      The Swiss Water Process is popular among its advocates because it does not use chemicals. Instead, a green coffee extract is used. This green coffee extract is almost caffeine-free. Due to chemical solubility laws, the caffeine will move from an area of higher concentration (the bean itself) to an area of lower concentration (the extract). Since the extract contains essential oils and the other valuable components of the bean, mostly caffeine seeks its way into the extract and leaves behind the desirable components of the coffee. Done properly, this organic method successfully removes 94 - 96% of the caffeine while it retains more of the flavor compounds present in the essential oils than the chemical methods. Keep in mind that Swiss Water Process coffee beans are generally more expensive than beans treated with a chemical solvent. This is due to the fact that Swiss Water Processing almost always accompanies high-quality arabica beans, while chemical processes are used on both arabica and robusta beans.

The Chemical Solvent Method
     The chemical solvent method is the most commonly used method for removing the caffeine from coffee. Chemical methods remove the caffeine better than the Swiss Water Process method because the solvents used can target caffeine most evenly and effectively. Common solvents include methylene chloride, ethyl acetate, and highly pressurized carbon dioxide. After the green beans are moistened they are then immersed in the solvent. After the solvent performs its action, the beans are rinsed with water. After the beans have been rinsed, they are steamed. Residual solvents evaporate in the steam. The rinsing and evaporation systems collect the solvent for recycling and re-use. Any remaining solvent will be burned off in the roasting process. The chemical caffeine method will remove 96 - 98% of caffeine.

The Supercritical Carbon Dioxide Method
     The Supercritical Carbon Dioxide method is a chemical method that is somewhat dissimilar to the other chemical methods; therefore it deserves special attention. This method uses carbon dioxide at 250 - 300 times normal atmospheric pressure. Carbon dioxide in this form looks like a liquid in terms of its density, but it has the viscosity of a gas. It is a very effective solvent at the high pressures. When the coffee beans are exposed to the solvent, the caffeine migrates to the solvent. When the removal of caffeine is complete, the now caffeine-rich carbon dioxide is passed through either an activated charcoal bed or a bath of water to absorb the caffeine for re-use. Like other chemical methods, the Supercritical Carbon Dioxide method removes 96 - 98% of the caffeine. Carbon dioxide is inexpensive to obtain and non-toxic.
One might compare a naturally mellow (low acidity) cup of caffeinated coffee with a decaffeinated version of a high acidity coffee. If you prefer a coffee that is known for bitterness or acidity in the caffeinated version, the same coffee in a decaffeinated state will taste "flat" in comparison. At the same time, the other characteristics of that coffee will be brighter since they aren't masked by so much bitterness or acidity.
     Until a method is developed which will completely eliminate caffeine while preserving other flavor constituents of coffee, we will have to tolerate these imperfect methods. The best thing to do is to try several different brands of decaffeinated coffee until you settle on the one or two that taste the best and feel as though they have the least amount of caffeine.
     People with heart problems should avoid caffeine consumption because of its effects on blood pressure and heart rate. Fatalities are likely to occur only with intravenous administration. Non- tolerant individuals generally experience elevated heart rate, blood pressure, and over all enbergy level following ingestion. Users often report temporary increase aleartness, physical endurance, strength and mental ability although no clinical research unequivocally supports this claims. unpleasant sensations such as nausea,dizziness and jitters occur less comonly. Caffeine is a diuretic vasoconstrictor and an addictive substance that may cause withdrawal symptoms including headaches and fatuige. The list of caffein's immediate effects could go on.
     The biochemical action of caffeine is unknown. several possibilities exist. 1) Caffine mobilizes calcium, lowers the excitability threshold in muscles and prevents the re-uptake of calcium. 2) Caffeine acts as an inhibits phospodiesterase from degrading camp. 3) Caffeine acts as an adenosine antagonist. Theories one and two do occur, however, doses required to yield the observed effects do not occur in vivo. The third mechanism is most plausible, though many textbooks neglect it when discussing caffeine.
     The controversy exists over possible consequences of regular consumptions over a long a time period. Pancreatic, renal, bladder, ovarian, breast, gastric, colorectal, prostate, other cancers and non-Hodgkin's lymphoma are blamed on caffeine. Some research shows a positive correlation but repeated studies failed to duplicate the results.Some studies neglected confounding factors such as tobacco.Some data indicates carcinogenic properties. Though no clinical conclusion can be drawn, many experts feel dat caffeine is not a cause of cancer.
     Caffeine also is believed to elevate serum cholesterol levels. Testing this issue always included caffeineted versus decaffeniated coffee, with data typically showing a slight decrease in cholesterol levels.All data indicating an increase in cholesterol level are now attributed to constituents in coffee such as cafestol and kahweol. However, only unfiltered coffee is harmful.
     Caffeine's effect on the reproduction and fetuses is in question. Most data retrieved from research is not statistically significant in favor of deleterious effects. Morever, most effects occur from daily doses over 300 mg. Data strongly suggests caffeine impairs the ability to conceive, increases spontaneously abortion and retards fetal growth.
     Most data retrieved from research is not statistically significant in favor of deeterious effects. Moreover, most effects occur from daily doses over 300 mg. Data strongly suggests caffeine impairs the ability to conceive, increases spontaneous abortions and retards fetal growth
     Too much caffeine may not be good for complex reasoning tasks, but it can improve mental speed related tasks. These are some of the results of research by Dr. Paula Mitchell, now working at working at the Alfred Hospital in Melbourne.
     In 1989 Paula carried out a study which looked at 3 groups of volunteers (around 8 people in each group) divided into low, moderate and high caffeine users. The volunteers visited the lab 8 times at different times day and night (7am, 1pm, 7pm, 1 pm) . Before the test began they swallowed either the caffeine capsule or a placebo capsule. In the lab they were given a series of performance tests covering short term memory, mental arithmetic, verbal reasoning (which is like logic), and a serial seach task ( which is a measure of vigilance.
     Caffeine actually improve performance in more simple mental tasks like searching for one paticular letter in a string of printed letters. Mental speed is the critical thing in this test.
     Caffeine improve performance best at the 7am testing time - when the body's 24 hour rythm of arousal is at its lowest.
     By contrast Mitchell found that the high caffeine user group didn't perform as well as the others on more complex tasks such as verbal reasoning.

EFFECT ON SLEEP
     Sleep results from the complex interaction of multiple neurotransmitter systems and the influences of sleep regulatory systems with other mechanisms (e.g., those which control temperature, respiration, and blood pressure). Thus, the observation of a drug's effect on sleep is relatively straightforward, but the interpretation of the mechanisms of its actions is very difficult. A drug-induced increase in sleep, for instance, might result from a "direct" effect on sleep mechanisms, or alternatively might result from a reduction in processes which are incompatible with sleep (e.g., anxiety or pain), or it might alter other systems that affect sleep (e.g., temperature or circadian processes). Moreover, many of the pharmacologic probes thought to have a specific effect on one neurotransmitter system may influence others as well. Clonidine, for instance, an alpha-2 noradrenergic agonist, has been reported to alter serotonin function as well. A drug's acute actions may also differ from when it is administered chronically. Thus, interpretations of the mechanism by which drugs influence sleep must be made with caution.
    EFFECT OF AN ADENOSINE ANTAGONIST, CAFFEINE, ON SLEEP IN A NORMAL SUBJECT FIGURE 2Stimulants. Dextroamphetamine and pemoline (Figure 3), which enhance catecholamine and dopaminergic activity, increase sleep latency, decrease total sleep time, and greatly reduce REM sleep. The REM sleep reduction effect is due to increased wakefulness, in contrast to drugs which primarily alter noradrenergic or serotonergic activity, in which REM sleep reduction occurs regardless of changes in total sleep or wakefulness. Wakefulness can also be increased by the beta-carbolines, which bind to the benzodiazepine recognition site but which have opposite effects, and hence are considered "inverse agonists."

    Caffeine is the most important chemical in coffee. It is an odorless and slightly bitter solid. Caffeine mostly affects the brain, kidneys, and the cardiovascular (heart and blood vessels) system, but it also increases metabolism and breathing. A five ounce serving of regular coffee contains about 90-125 milligrams of caffeine; whereas, an equal amount of tea only contains 30-70 milligrams of caffeine. A soft drink only has about 37 milligrams of caffeine per five ounces.

    Coffee has several effects on the human body:
    It helps to increase circulation of the blood;
    It can cause nervousness and loss of sleep when taken in large amounts;
    It can speed up a person's thoughts � it produces a feeling of well-being;
    It gives some people the ability to memorize simple numbers, concepts, and thought sequences easier.
    If you drink one or two cups several times a day, coffee will have little effect on the cardiovascular system. However, if you drink three to four cups several times a day, it will slow your pulse rate, raise blood pressure, contract blood vessels that are right under the skin, and dilate blood vessels of the kidneys, muscles, skin, and heart, makes the heart contract harder while it's pumping.

EFFECTS OF CAFFEINE IN CANCER PATIENTS
   Speculation that caffeine could be a possible cancer risk has not been confirmed by scientific investigations. A number of human epidemiological studies have examined the increased risk of developing cancer at different locations in the body. Two recent studies of large numbers of people in Norway (16,600) and Hawaii (7,350) found no relationship between coffee consumption and cancer risk.
   This confirms the earlier position of the American Cancer Society, which stated, "Available information does not suggest a recommendation against the moderate use of coffee. There is no indication that caffeine, a natural component of both coffee and tea, is a risk factor in human cancer."

BREAST CANCER
   All clinical studies to date suggest that caffeine consumption does not increase the risk of breast cancer. Researchers in a worldwide examination of 100,000 deaths due to breast cancer concluded that the data do not support an association between caffeine intake and the development of breast cancer.
   Research has also shown that caffeine intake is not related to the development of fibrocystic breast disease (FBD), a condition with benign fibrous lumps in the breast. Both the American Medical Association's Council on Scientific Affairs and the National Cancer Institute have published reports stating there is not an association between caffeine intake and the incidence of FBD.