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Megan Ward

October 24, 2008



The alarm sounds. Groggy and tired we wake up dreading the start of yet another day. Luckily, with the help of caffeine many feel confident that they can endure the day, at least attentive and awake. Many Americans and people across the world find themselves addicted to some form of caffeine. Caffeine is a common ingredient in coffee both decaffeinated and caffeinated, tea, soft drinks, weight loss pills, energy drinks, and several other foods, beverages, and supplements. Caffeine can be seen as an American way of life; Starbucks occupy the corners of every city and soda machines fill the hallways of many schools. With caffeine consumption so high some would fear that it would have adverse effects on health but according to popular beliefs there are health benefits to caffeine. However, do these popular beliefs about beloved caffeine hold up to scientific knowledge?


Sources of Caffeine

Caffeine Content



Plain, brewed 8 oz

135 mg

Instant 8 oz

95 mg

Espresso 1 oz

30-50 mg

Plain, decaffeinated 8 oz

5 mg



Green tea 8 oz

25-40 mg

Black tea 8 oz

40-70 mg

Soft Drinks


Coca-Cola Classic 12 oz

34.5 mg

Diet Coke 12 oz

46.5 mg

Dr. Pepper 12 oz

42 mg

Mountain Dew 12 oz

55.5 mg

Pepsi-Cola 12 oz

37.5 mg

Sunkist Orange 12 oz

42 mg

Energy Drink


Full Throttle, 16 oz

144 mg

Red Bull, 8.5 oz

80 mg

SoBe No Fear

158 mg

Chocolates or Candies


Candy, milk chocolate 1 bar (1.5 oz)

9 mg

Candy, sweet chocolate 1 bar (1.45 oz)

27 mg

Cocoa mix, powder 3 tsp

5 mg

Puddings, chocolate, ready-to-eat 4 oz

9 mg

Medicine: Over the Counter



65 mg

Bayer Select Maximum Strength

65.4 mg

Midol Menstrual Maximum Strength

60 mg

NoDoz 100 mg

32.4 mg

Pain Reliever Tablets

65 mg


200 mg





What is Caffeine exactly?

Caffeine is a small white, crystalline, bitter alkaloid, C8H10N4O2, which serves as a nervous stimulant (


Image:Caffeine USP.jpg




Although caffeine may increase nervousness, heart rate, and blood pressure, the advantages of caffeine out weigh its disadvantages ( /caffeine-myths-and-facts). Many sources attribute caffeine to health benefits. It lowers the risk of diabetes, lowers the risk of cavities, lowers cancer risk, and helps to prevent both Parkinsonís and Alzheimerís, two cognitive diseases. †According to a popular menís health website, men who drink 4 cups of caffeinated coffee a day are half as likely to develop Parkinsonís disease ( ?site=MensHealth& channel=nutrition& 02a4e7110VgnVCM20000012281eac____&page=3). Claims have also been made that caffeine consumption enhances physical activity. In fact, consuming 140 to 400 mg of caffeine 30 to 60 minutes prior to exercise can improve speed and endurance and make working out easier ( lth&channel=nutrition& gnVCM20000012281eac____&page=3). Not only does caffeine increase exercise ability, but it is also connected to weight loss.



How Caffeine Works?

According to the articles and quotes from scientist within the articles on the web, caffeine works specifically by inhibiting the binding of adenosine to its receptor. Adenosine naturally works by slowing down the body. When caffeine blocks the adenosine receptor, the nervous system no longer has a means to keep it from getting too excited at the cellular level ( Caffeine also works by releasing dopamine. Dopamine acts by stimulating the grey matter in the brain which is responsible for alertness, problem solving, and pleasure ( channel=nutrition&c




What do Scientist Have to Say About It?


Caffeine and Physical Performance


According to popular belief, caffeine usage increases physical performance during exercise. Hogervorst et al (2008) conducted a study in which they found that caffeine improves physical and cognitive performance during exhaustive exercise. The purpose of the study was to determine the effects of caffeine ingestion on physical and cognitive performance. A group of 24 trained cyclists consumed a performance bar containing caffeine before cycling and at varying times throughout (after 55 minutes and then after 115 minutes), and after the cycling experiment. Their cognitive abilities were also measured before, throughout (after 70 minutes and 140 minutes of cycling), and after cycling. The cyclistsí cognitive ability was measured by a computerized test and rapid visual information processing test. There was also a control group which received a non-caffeinated performance bar and performed the same task. Caffeine intake significantlyImage Preview improved endurance and cognitive ability during, throughout, and after exercising.


On the other hand a study conducted by Hunters et al (2002) proves the contrary. They found no significant difference between caffeine ingestion in comparison to a placebo. In the experiment, Caffeine or a placebo was ingested by eight highly trained cyclists in a 100-km trial every 15 minutes until the end of the trial. The task of the cyclist was to finish the 100-km as fast as possible. The cyclists in the caffeine group had higher heart rates, but overall performance or completion was not altered by caffeine intake.


It is important to note that both of the above studies involved trained cyclists. These results may not be present in the exercise performance of untrained individuals. Likewise, the level of difficulty of the cognitive test is not identified and could have an effect on the cyclistsí ability to complete it with or without caffeine. Cognitive abilities also differ from person to person. It may be necessary to test the same person with the caffeine in one trial as well as the placebo in another trial.



Caffeine and Parkinsonís and Alzheimerís Disease

Caffeine is believed to have cognitive improvement abilities. To investigate this claim several studies have been conducted involving Parkinsonís and Alzheimerís disease. In a study conducted by Nakaso K. et al(2008), caffeineís beneficial effect to Parkinsonís patients was analyzed. Human dopaminergic neuroblastoma cells were used to model cells that occur in Parkinsonís disease patients. The cells were placed on a medium. The cells were then exposed to a toxin. Directly after the toxin was added to the cell medium varying amounts of caffeine or a placebo were added to the cells. In the cells where caffeine was added there was less apoptotic nuclei and a decreased percentage of apoptotic cell death. Basically, Caffeine acted as a neuroprotective agent. A criticism is that this experiment was not actually conducted on human beings but because the cells model Parkinsonís patientsí cells, it shows promise in human patients.


Similarly, Maia et al. (2002) conducted a case control study where they evaluated the effects of caffeine on Alzheimerís. The study was among 54 patients with probable Alzheimerís disease and 54 controls that were cognitively normal and matched by age. The probable Alzheimer patients had a daily intake of 73.9 mg of caffeine during a 20 year period preceding their Alzheimer diagnosis. The controls had a daily intake of 198.7 mg of caffeine during the same 20 year period. The scientist concluded that caffeine intake is associated with a significantly lower risk of Alzheimerís disease. It is important to note that there are other risk factors and protective factors that effect Alzheimerís diagnosis which the patients may have been exposed to. Genetics is also a large factor that predisposes one to Alzheimerís disease. †††



Caffeine and Weight Loss

Body weight loss along with weight maintenance in relation to caffeine and green tea intake was examined by Westernp-Plantenga et al (2005). The objective of the study was to investigate the effects of a green tea-caffeine mixture in weight loss in moderately obese subjects in relation to habitual caffeine intake. 90 males and females who were moderately obese, 25-35 BMI participated in the study. The green tea caffeine mixture was in the form of a pill capsule and was compared over time to a placebo. The pill was taken before meals at varying doses; the placebo was taken at the same time and in the same dosages in the control group. The study concluded that high caffeine consumers reduce weight, fat mass, and waist circumference more than low caffeine consumers and placebo consumers. In habitual low caffeine consumers, the green-tea mixture improved weight maintenance.


Although the study goes into great detail about caffeine dosages with meals, it does not go into detail about the exact meals that were eaten in each group. The meals that were eaten could have affected the amount of weight loss and weight maintenance. Similarly, the study does not give detail about any possible physical activity conducted by the males and females. This confounding factor could also have contributed to weight loss and weight maintenance. †



Caffeine does have several health benefits, varying from cognitive abilities to weight loss. However, before self medicating to prevent cognitive diseases or to keep your slim shape, more studies need to be conducted to strengthen the fidelity of the presented studies. In addition, consider the addictive effects of caffeine. Caffeine is good in moderation. ††







Hogervorst E., Bandelow S., Schmidtt J. Jentjens R., et al.(2008). Caffeine improves physical and cognitive performance during exhaustive exercise. Med Science Sports Exercise, 40(10), 1841-1851.


Hunters A. M. , St. Clair Gibson A., Collins M., Lambert M., Noakes T. D.(2002). Caffeine ingestion does not alter performance during 100-km cycling time-trial performance. International Journal Sport Nutrition and Exercise Metabolism, 12(4), 438-52.


Maia L. de Mendinca A.(2002) Does caffeine intake protect from Alzheimerís disease? European Journal of Neurology, 9(3), 377-382.


Nakaso K., Ito S., Nakashima K.(2008). Caffeine activates the P13K/Akt pathway and prevents apoptotic cell death in Parkinsonís disease model of SH-SY5Y cells. Neuroscience Letters, 432(2), 146-150.


Westernp-Plantenga M.S., Lejeune M.P., Kovacs E.M.(2005). †Body Weight Loss and Weight Maintenance in Relation to Habitual Caffeine Intake and Green Tea Supplementation. Obesity Research Journal, 13(7), 1195-1204.




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