Facts and Food Sources of Caffeine


Caffeine is a chemical compound which is formed by plants. It is classified as methylxanthine alkaloid. It acts as a stimulator for nervous system. In pure form, the powder is white with slightly bitter taste and is odorless. Presently, there are 63 various plant species known that contain caffeine. Coffee, tea and chocolate are the most common food source of caffeine in human diet.

Caffeine is a stimulant that makes us feel more alert and energetic, decreasing feelings of fatigue during exercise. Caffeine has been shown to increase the use of fat asa fuel during endurance exercise, which spares muscle glycogen and improves performance. Energy drinks that contain high amounts of caffeine, such as Red Bull, have become popular with athletes and many college students. These drinks should be avoided during exercise, as severe dehydration can result due to the combination of fluid loss from exercise and caffeine consumption. It should be recognized that caffeine is a controlled or restricted drug in the athletic world, and athletes can be banned from Olympic competition if urine caffeine levels are too high. However, the amount of caffeine that is banned is quite high, and athletes would need to consume caffeine in pill form to reach this level. Side effects of caffeine use include increased blood pressure, increased heart rate, dizziness, insomnia, headache, and gastrointestinal distress.

Food Sources

Food name Weight (g) Caffeine (mg)
Coffee beans 40 336
Cocoa powder 86 198
Candies 170 105
Coffee 248 92
Milk coffee 262 73
Mousse 808 57
Mocha 265 53
Black tea 473 52
Mocha 13 47
Carbonated limeade 253 46
Chocolate frosting 388 23
Candies 28.35 19
Green tea 270 14
Unsweetened chocolate 28.35 13
Green green 260 10
Semisweet chocolate 14.5 9
Milk chocolate 40 8
Waffles 70 7
Chicory beverages 29.9 6
Black tea with lemon 265 5



In adults, physiological effects of caffeine could be observed at the dosages of 100 to 200 mg. As caffeine is absorbed readily by the body, the blood levels reach its peak about 30 minutes after ingestion. In adult, the clearance rate from blood requires several hours in adult to several days in newborn. The use of oral contraceptives and pregnancy lowers the clearance rate. Moreover, people trying to quit smoking should prevent intake of caffeine as to prevent from increasing caffeine levels in blood and crave for nicotine.

Health Benefits of Caffeine

  1. Alertness

It is experienced by blocking adenosine receptors in brain. Brain is signalized by adenosine for the body to slow down and sleep. Study conducted on 36 participants shows that caffeine showed dose dependent effects on attention and alertness. Usually when people do not drink caffeinated products and took high doses of caffeine, they had higher increase in brain function. Study conducted on 20 sleep deprived participants, regular dose of 800 mg of caffeine assist promote reaction speed and accuracy. Caffeine makes people alert and awake while driving.

  1. Pain relief

Caffeine lowers inflammation and assist in blocking perception of pain in brain.

  1. Endurance

Caffeine influences the muscles to utilize glycogen by allowing them to function longer before fatigue is set in. It assists anaerobic exercises such as jumping or sprinting. This effect may promote anti-fatigue effects and by promoting endurance, power output and physical strength. Study conducted on 16 trained young men shows that caffeine promoted upper and lower body muscle force. It enhanced smaller muscle. It promoted smaller muscle strength by 6% and larger muscles by above 13%. It has positive effect on metabolic rate and increases uptake of oxygen. With an intake of more oxygen and utilizing maximum exertion, one could have better athletic performance.

  1. Motivation

It promotes levels of dopamine which forms positive state of mind.

  1. Neurological conditions

Caffeine prevents or slow down onset of Parkinson’s disease and Alzheimer’s disease and is also able to treat some hyperactivity problems.

  1. Gain in weight

Caffeine is a well-known ingredient in fat burning supplements. It enhances usage energy and improve metabolic rate preventing weight gain. Study conducted on ten lean and ten obese women, both groups formed more body, spent more energy. Caffeine is beneficial for managing weight loss. 2100 participants, people with 2-4 cups of caffeinated coffee a day.

  1. Parkinson’s disease

Being neuroprotective, it could prevent degeneration of cells that occurs in Parkinson’s. Moreover, it inhibits adenosine receptors, improves mobility and motor functions in Parkinson’s patients. Study on 61 patients shows that 100 mg of caffeine when taken twice daily for three weeks lowered movement slowness. One study shows that intake caffeinated coffee had low chances of developing Parkinson’s disease. In addition, study conducted on 29000 participants, both coffee and tea drinkers had lower the chances of Parkinson’s disease.

  1. Improve memory

Study shows that moderate intake of caffeine i.e. 200 mg promote memory performance. Though results were not significant, high to moderate caffeine users had promote memory recall compared to low users. Other study conducted on 140 young adults in two experiments. Participants who took caffeinated coffee in the morning had better performance on memory recall test in the early morning but not in the late afternoon. Review shows inconsistent effects on memory. It is beneficial for promoting memory during simple tasks but not on complex ones.

  1. Liver health

Caffeine is related with lowering chances of liver fibrosis. Study conducted on 306 patients having fatty liver disease showed that people who drank caffeinated coffee had low severe liver scarring in comparison to one who did not drink caffeinated coffee. Survey of 177 liver biopsy patients shows that intake of caffeine was related with low severe liver tissue scarring. Daily intake of two cups of coffee helps to lower severity of tissue scarring. Study conducted on 458 healthy individuals and 274 cirrhosis cases shows that caffeinated coffee prevented chronic liver damage.

  1. Skin health

Antioxidant properties in caffeine help to protect skin cells against UV radiation and skin aging due to sun exposure. Moreover, it is used in cosmetic products to prevent accumulation of fat and formation of cellulite.

Side effects

  • When used before bedtime, it could interfere with sleep.
  • Caffeine in large quantities could cause severe headaches.
  • Caffeine shows the common side effects such as restlessness, nervousness, excitement, dizziness, flushed face, increased urination, diarrhea, vomiting, muscle twitching, rambling flow of thought and speech.

Recommended intake

Low to moderate intake: 130-300 mg/day

Moderate intake: 200-300 mg/day

High doses: More than 400 mg/day

Heavy consumption: More than 6,000 mg/day

Moderate intake of caffeine refers two to four cups of brewed coffee per day. In the U.S. average daily intake of caffeine is 280 mg/day, though it is estimated that about 20 to 30% have daily intake exceeding 600 mg. People sensitive to caffeine might develop side effects even at low doses.




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