Caffeine: a boon or bane

Vikas Kumar (Department of Food Technology and Nutrition, Lovely Professional University, Phagwara, India)
Jaspreet Kaur (Department of Food Technology and Nutrition, Lovely Professional University, Phagwara, India)
Anil Panghal (Department of Food Technology and Nutrition, Lovely Professional University, Phagwara, India)
Sawinder Kaur (Department of Food Technology and Nutrition, Lovely Professional University, Phagwara, India)
Vanshika Handa (Department of Food Technology and Nutrition, Lovely Professional University, Phagwara, India)

Nutrition & Food Science

ISSN: 0034-6659

Publication date: 12 February 2018



The purpose of this paper is to explore the sources of caffeine and its utilization in different food products, along with its impact on human health in terms of benefits and adverse effect.


The papers reviewed were selected based on the following key descriptors such as caffeine, sources, trends of consumption, utilization, benefits and adverse effects, regulation and labelling.


There are many physiological effects of caffeine on respiratory, cardiovascular, gastrointestinal, reproductive and central nervous system. It has a positive effect in reducing the risk of diabetes, Alzheimer’s disease, Parkinson’s disease and liver injury and, at the same time, in improving mood, psychomotor performance and immune response. On the other hand, the negative effects of caffeine include addiction, cancer, heart diseases, insomnia, gastrointestinal disturbances and intoxication. As caffeine, when taken in large amount, is harmful, therefore as per the regulatory bodies, its concentration should not exceed the set limit, and its presence needs to be listed on the label of that particular food product. In a nutshell, it can be said that caffeine acts as a boon as well as bane because it possesses both beneficial and adverse effects.


This is a unique and comprehensive review that will provide a brief overview of sources, utilization, healthful as well as harmful effect of caffeine to the readers.



Kumar, V., Kaur, J., Panghal, A., Kaur, S. and Handa, V. (2018), "Caffeine: a boon or bane", Nutrition & Food Science, Vol. 48 No. 1, pp. 61-75.

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Copyright © 2018, Emerald Publishing Limited


Caffeine (1, 3, 7-trimethylxanthine) is an alkaloid which is a large class of organic compounds, belonging to methylxanthine family. It is naturally present in the seeds, leaves and fruits of more than 63 plant species (Wanyika et al., 2010; Del Coso et al., 2012; Geethavani et al., 2014). Generally found in coffee and tea, it is also present in kola nut which is chewed in Africa, yerba mate (usually taken with hot water in South America) as well as guarana seeds which is primarily added to soft drinks in Brazil. Caffeine is bitter to taste and is the most commonly used addictive drug. At least one caffeinated product is daily consumed by nearly 80 per cent of the world population. Caffeine consumption is most frequent through beverages such as coffee (71 per cent), soft drinks (16 per cent) and tea (12 per cent) (Nehlig, 1999). The average intake of caffeine on daily basis varies distinctly all over the world being more than 300 mg/day in Denmark, Finland and Brazil. Also, the amount of caffeine consumed by the adult population in the USA, UK, Canada and Australia is 168, 202, 210 and 232 mg per day, respectively (Heckman et al., 2010).

Caffeine gets readily absorbed in the body, and it reaches the brain within 5 min after its consumption (Nehlig 1999; Baribeau, 2014) and is also eliminated with an average half-life of five hours from the body (Heckman et al., 2010). It performs various physiological functions involving its effect on the respiratory (Benowitz, 1990; Franco et al., 2013), cardiovascular (Butt and Sultan, 2011), gastrointestinal and the central nervous system (Baribeau, 2014). Caffeine is generally consumed for its role to work as a mild nervous chemical stimulant towards drowsiness and fatigue (Wolde, 2014). Caffeine has many pharmacological as well as physiological effects on the human body. The various beneficial effects of it include the reduced risk of diabetes, liver injury (Wolde, 2014), Parkinson’s disease and Alzheimer’s disease (Messina et al., 2015), and improved psychomotor performance, alleviated mood (Giles et al., 2012) and improved overall immune response (Wolde, 2014). On the other hand, caffeine pose many adverse effects on the body such as it causes addiction (Butt and Sultan, 2011), anxiety, insomnia (Baribeau, 2014), coronary artery disease, osteoporosis, gastritis, anaemia, still-births (Wolde, 2014) and other behavioural changes. This review focuses on the various sources and benefits and, at the same time, addresses the adverse effects of caffeine. The ways of using caffeine to develop different food products, such as tea, energy drinks, soft drinks, cocoa products and coffee-based beverages, have also been discussed in this review to provide a brief overview to the readers.


The main aim of the literature searching strategy was to explore the sources of caffeine, its utilization in different food products, along with its impact on human health in terms of benefits and adverse effect. A wide variety of the relevant publications were identified through searching over the electronic databases (Sciencedirect, PubMed, SciELO, Google scholar, Linkspringer and Researchgate) on the basis of different keyword such as caffeine, sources, trends of consumption, utlization, benefits and adverse effects, regulation and labelling published before 2016. After the search of suitable literature, 84 papers were reviewed which provided the overviews of these aspects.

Sources of caffeine

Natural sources

The most important sources of caffeine are coffee (Coffea spp.), tea (Camellia sinensis), guarana (Paullinia cupana), maté (Ilex paraguariensis), kola nuts (Cola vera), cocoa (Theobroma cacao) and caffeinated soft drinks including energy drinks [Frary et al., 2005; Fulgoni et al., 2015; EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2015].

Coffee is cultivated worldwide, and the most important producers are Brazil, Vietnam, Indonesia, Columbia and Ethiopia. All the commercial coffee species including Coffea Arabica originate from Africa (Pohlan and Janssens, 2010). Whereas, tea is the most widely consumed beverage after water (Kumar et al., 2016; Kumar and Joshi, 2016) and contains caffeine as an active dietary component. It helps to upgrade performance in tasks requiring persistent effort and attention (Bryan, 2008; Glade, 2010). The major tea-producing countries are India, Sri Lanka, Java and Sumatra, Japan and Kenya (Willson and Clifford, 2012). Guarana, a product of a climbing shrub (Paullinia cupana) is native to Brazil, Bolivia, Peru, Uruguay and Venezuela. Being rich in caffeine, guarana and kola nuts enjoy great popularity as they serve as a stimulant (Morton, 1992; Schimpl et al., 2013; Muhammad and Fatima, 2014). Cocoa is primarily used in the production of chocolates, and Côte d’ Ivoire is ranked as the first largest producer of cocoa beans followed by Ghana. However, Ghana is considered as the world leader in the production of premium quality cocoa beans (Ntiamoah and Afrane, 2008; Fowler and Coutel, 2017).

Several caffeinated products are available in the market which is attracting consumer’s attention. Caffeine is used for the preparation of many coffee and coffee-based beverages (instant coffee, Espresso, Cappuccino, Latte, decaffeinated coffee, coffee liqueur), tea (iced tea, decaffeinated tea, all kinds of herbal tea), energy drinks (Red Bull, Monster, Rockstar, Full Throttle, NOS, AMP energy drink, Triple X, Cloud 9, Burn) and soft drinks (diet cola) and cocoa products (dark chocolate, hot chocolate, milk chocolate bar, brownie, chocolate yoghurt, chocolate pudding, chocolate ice-cream). A complete detail of the different type of coffee, tea, energy drinks, soft drinks cocoa-based products along with their serving size and caffeine content is presented in Table I.

Drug as a source of caffeine

The typical caffeine-containing drugs contain generally 30-100 mg caffeine per tablet or capsule, while over the counter drugs contain extensive range, namely, 150-200 mg per tablet or capsule, based on the type and brand of the product (Barone and Roberts, 1996).

Caffeine consumption and safe limits

Caffeine is commonly consumed by various population groups such as children, adolescents and adults (Heckman et al., 2010) as a stimulant of the central nervous system (Nehlig et al., 1992; Franke et al., 2012). It is consumed widely for its role in enhancing mood, alertness, physical performance, attention and reaction time (Heckman et al., 2010). Trend of caffeine consumption by adolescents and young adults has increased drastically from the past decade due to increased intake of coffee and energy drinks such as Red Bull and Monster (McIlvain et al., 2011).

Caffeine is consumed all over the world either through natural sources or synthetic food sources. The per capita consumption of caffeine by all age groups is approximately 120 mg/day (Knight et al., 2004; Wolde, 2014), and the per capita consumption of caffeine in the UK, Finland and Sweden ranges from 100 to 400 mg per person per day (Yenisetti and Muralidhara, 2016). Consumption level of caffeine by children is notably less as compared to the adults. The chief sources of caffeine for children and young adults are soft drinks and tea, whereas for adults older than 25 years, it is primarily derived from coffee and tea (Knight et al., 2004; Wolde, 2014). In Australia, the highest recommended intake of caffeine is 160 mg per day (Peacock et al., 2016). It has been found that caffeine consumption up to 400 mg per day from all the sources including natural as well as synthetic does not tend to raise the safety concerns for adult population (excluding pregnant women) as well as children. The safety limit for the pregnant and lactating women is 200 mg per day [EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2015]. Caffeine is unlikely to produce any negative effects when consumed in moderation by majority of population but excessive consumption may lead to various health problems. Thus, a balance needs to be maintained to reduce or prevent the adverse effects associated with its over-consumption (Smith, 2002; Heckman et al., 2010).

Caffeine is included in the GRAS (generally recognized as safe) list, as it is used in beverages like cola in accordance with the good manufacturing practices, but the level should not exceed 200 ppm which corresponds to 71 mg of caffeine per 12 ounze serving of cola-type beverages and is considered safe for consumption as per the statement of GRAS (Rosenfeld et al., 2014). Setting up any international standard for caffeine consumption is not easy due to the wide variety of products and varying amounts of caffeine consumed in each country. For the beverages where caffeine is added in the synthetic or natural form, the daily intake guidelines and regulatory upper limits have been set by the Food and Drug Administration (FDA). The general range for soft drinks, energy drinks and other caffeinated beverages is 100 to 350 ppm (Heckman et al., 2010). On 21 October 1980, in the federal register, FDA proposed to delete caffeine from the GRAS list, as the added food ingredient. To restrict the existing uses and levels of use of caffeine as an added food ingredient, clear information should be declared in the ingredient list on product label. For resolving the issues concerned with the teratogenic and fetotoxic properties of caffeine, FDA further projected to declare caffeine as a food additive on an interim basis pending the completion of safety studies (Rosenfeld et al., 2014).

Health effects

Beneficial effects of caffeine

Caffeine and caffeinated products such as energy drinks, cola beverages and chocolates are very popular all across the world and are constantly being advertised. Caffeine offers different benefits including its role in increasing alertness, vigilance, mood as well as psychomotor and cognitive performance (Rogers and Dernoncourt, 1998; Glade, 2010). It helps to reduce the risk of diabetes by exerting positive effects on glucose metabolism, has protective effect against Parkinson’s disease and lowers the risk of Alzheimer’s disease. Caffeine may also act as an antioxidant. Therefore, it helps to prevent different diseases by protecting cells in the body against oxidative damage (Wolde, 2014) and raise the overall immunity of a person. A complete detail regarding the health benefits of caffeine is presented in Table II along with its specific remarks as given by the researchers.

Adverse effects

Although it has many health benefits and has long been used by the people for its stimulating effects, it also comes with various health hazards. Caffeine consumption is linked to the risk of developing coronary artery disease, osteoporosis, gastritis, anaemia and still-births (Wolde, 2014). Other adverse effects of caffeine include sleep deprivation, increased heart rate and blood pressure, central nervous system disorders, vasodilation, trembling, seizures, urticaria, headaches, increased body temperature and behavioural changes. In people consuming caffeine on regular basis, it has been found that the cessation of caffeine results into many unfavourable changes such as increased occurrence of headaches, increased drowsiness and fatigue as well as lowered alertness (Rogers and Dernoncourt, 1998; Juliano et al., 2012). The various ill-effects of excessive caffeine consumption include addiction, hormone-related cancers, increased risk of cardiovascular diseases, anxiety, insomnia, intoxication and nutrient malabsorption. It affects bones by decreasing calcium absorption in human small intestine. It is also known to affect gastrointestinal, respiratory and reproductive health. A complete detail of the adverse effects of caffeine is shown in Table III.

Caffeine labelling

According to the laws and regulations of the USA, neither caffeine nor caffeine-containing ingredients has any special regulatory status for labelling on food or dietary supplements. As per the FDA regulations, beverage companies need to list the presence of caffeine as an ingredient on the product labels. But there is no such FDA requirement to list the precise amount of caffeine present in a particular food product (Mattia, 2013). The amount of caffeine used as a dietary ingredient in dietary supplements should be listed. The nutrient content must be labelled on the food, but caffeine is not a nutrient. Therefore, the amount of either natural or added caffeine is not required to be labelled. It is technically feasible to label the quantitative amount of added caffeine in a food, but the amount of caffeine that naturally occurs in plant-based products (coffee, chocolate) varies according to the variety, location, environmental factors, agricultural practices, etc. Thus, it is quite challenging to mention the accurate quantitative amount of naturally occurring caffeine in a product. All ingredients (including caffeine) in a retail food product need to be listed by both their common as well as usual names on the product label. The ingredients present in the packaged food material need to be mentioned in descending order of their proportion by weight (Rosenfeld et al., 2014).

In accordance with the American Beverage Association, some soda manufacturers voluntarily label the amount of caffeine. More recently, same trend has been followed by manufacturers of energy drinks. On the other hand, some products contain advisories against the use of caffeine by children, pregnant women and individuals sensitive to caffeine (Mattia, 2013).


Due to the stimulating effect and other health benefits of ready to drink beverages (energy drinks and soft drinks) and non-alcoholic beverages (tea and coffee), these are attracting the young and adult population, respectively. But the impact of adverse effects of caffeine present in the above caffeinated beverages is more as compared to the health benefits. Therefore, the authoritative regulatory bodies as well as industrialists need to focus on the addition of caffeine to specific beverages to provide a safe product to the consumers. In this way, caffeine could prove to be a boon rather than a bane.

Different type of coffee, tea, energy drinks, soft drinks cocoa-based products along with their serving size and caffeine content

Food/beverage Serving size Caffeine (mg)
Coffee or coffee based beverages
Coffee, instant 250 ml 76-106
Espresso, brewed 30 ml 64-90
Cappuccino or Latte 250 ml 45-75
Decaffeinated coffee 250 ml 3-15
Coffee liqueur 45 ml 4-14
Coffee, instant, decaffeinated 250 ml 3-5
Decaffeinated espresso 30 ml 0
Tea or tea-based beverages
Iced tea, sweetened 1 can 15-67
Tea, leaf or tea bag
(black, flavoured black)
250 ml 43-60
Tea (green, oolong, white) 250 ml 25-45
Decaffeinated tea 250 ml 0-5
Herbal tea all variety 250 ml 0
Energy drinks/soft drinks
Energy drinks various type 250 ml 80-125
Diet cola 355 ml 25-43
Cola 355 ml 30
Red bull 250 ml 80
Triple X 250 ml 100
Cloud 9 250 ml 80-100
Burn 300 ml 320
Monster 100 ml 35.28-37.93
Rockstar 100 ml 35.28-36.16
Full throttle 100 ml 30.87-31.75
NOS 100 ml 35.28
AMP energy drink 100 ml 31.31
Cocoa products
Chocolate coated coffee bean, dark or milk chocolate 60 ml 338-355
Chocolate, dark 1 bar 27
Hot chocolate 250 ml 5-12
Milk chocolate bar 1 bar 8-12
Chocolate brownie 1 brownie 1-4
Yogurt, chocolate 175 gm 4
Chocolate pudding 125 ml 2
Ice cream, chocolate 125 ml 2

Source: Gilbert et al. (1976), Zoumas et al. (1980), Harland (2000), McCusker et al. (2003), Komes et al. (2009), Higgins et al. (2010), Heckman et al. (2010), Ogah and Obebe (2012), Sengpiel et al. (2013), Rosenbloom (2014), Baribeau (2014)

Beneficial effects of caffeine

S.No. Effect Key points/findings Reference
1 Reduced risk of Type 2 diabetes Coffee (a source of caffeine) consumption is linked with a lower risk of type 2 diabetes mellitus van Dam and Feskens (2002), Heckman et al. (2010), Kempf et al. (2010), Pourshahidi et al. (2016)
Caffeine intake has been found to decrease one’s sensitivity towards insulin, leading to decreased storage of glucose Greer et al. (2001), Keijzers et al. (2002), Van Dam and Hu (2005), Lane (2011), Butt and Sultan (2011)
Caffeine exerts positive effects on glucose metabolism through increased uncoupling protein expression and lipid oxidation leading to decreased glucose storage capacity which in turn reduces the extent of diabetes mellitus Van Dam(2006), Van Dijk et al. (2009), Butt and Sultan (2011)
High caffeine intake is linked with reduction in diabetes risk Wolde (2014)
2 Reduced risk of Parkinson’s disease (PD) Caffeine has neuroprotective effect and has the ability to block the adenosine A2A receptor and thus slows down the progression of PD George et al. (2008), Chen et al. (2001), Prediger (2010)
Coffee and caffeine decrease the risk of PD, but its efficacy is gender dependent due to the interaction of caffeine with the use of postmenopausal estrogens Butt and Sultan (2011)
Moderate doses of caffeine may have defensive effect against PD Messina et al. (2015), Pourshahidi et al. (2016)
3 Reduced risk of Alzheimer’s disease (AD) Moderate intake of caffeine on daily basis may lower the risk of AD Arendash et al. (2006), O’Keefe et al. (2013)
Caffeine decreases Abeta production caused by the reduced expression of Presinilin (PS1) as well as β-secretase (BACE), as these enzymes play a vital role in amyloid formation Butt and Sultan (2011)
Caffeine alone or in combination with chlorogenic acid may protect against degeneration of cognitive functions or other biological properties of AD in CNS Messina et al. (2015)
4 Mood and psychomotor performance Caffeine increases vigilance, boost mood and increase psychomotor and cognitive performance Rogers and Dernoncourt (1998), George et al. (2008), Christopher et al. (2005)
It increases mental alertness Smith (2002), Baribeau (2014)
Caffeine has a very consistent effect in all the cognitive domains including cognitive control, working memory and psychomotor performance Giles et al. (2012)
It has ergogenic effect as it enhances performance in endurance sports and helps to reduce fatigue Davis et al. (2003), George et al. (2008), Duncan et al. (2013)
5 Improve immune response Caffeine consumption helps to decrease the risk of several chronic diseases like diabetes mellitus, liver disease, Parkinson’s disease and cancer Higdon and Frei (2006), Wolde (2014)
Caffeine possesses antioxidant activity as it has a role in scavenging free radicals and hence protects against oxidative damage
Caffeine has chemoprotective effect. It has been found that caffeine-containing beverages (coffee) when consumed prior to radiotherapy against cervical cancer, reduced the occurrence of severe late radiation injury significantly
George et al. (2008), Souza et al. (2013)
George et al. (2008)
6 Reduced risk of liver injury Individuals consuming more than two cups of coffee or tea daily are less likely to suffer from chronic liver diseases as compared to the ones consuming one cup of coffee daily Wolde (2014)
Coffee (source of caffeine) has protective role against non-alcoholic cirrhosis, as it antagonizes the effect of hepatitis B and C infection Cadden et al. (2007), George et al. (2008), Pourshahidi et al. (2016)
7 Weight management Caffeine has thermogenic and lipolytic activity. It increases metabolism and thus plays an effective role in weight management Heckman et al. (2010)
Oxygen consumption and fat oxidation was found to increase after caffeine consumption which suggests its role in weight loss Greenway(2001)
8 Relieve pain Caffeine is helpful to treat headaches as it reduces pain. So, it is used in combination with certain analgesics for effective treatment Ennis(2014)

Adverse effects of caffeine

S.No. Effect Key points/findings Reference
1 Addiction High intakes of caffeine in the form of coffee cause addiction which leads to discomfort, headache and muscle pain Butt and Sultan (2011)
Caffeine contains adenine base. Thus, the structural resemblance of it with adenosine leads to the binding of adenosine receptors and causes addiction Johnson-Kozlow et al. (2002), Butt and Sultan (2011), Baribeau (2014)
2 Cancer Caffeine modulates the circulating estrogen levels and hence leads to the development of hormone-related cancers Hirose et al. (2007), Friberg et al. (2009),, Butt and Sultan (2011)
3 Heart problems Caffeine consumption leads to increased blood pressure as it has the potential to enhance the arterial stiffness thereby; it increases the risk of cardiovascular diseases Sudano et al. (2006), Butt and Sultan (2011)
Caffeine also stimulates renin secretion in kidney which causes vasoconstriction of blood vessels and interferes with the angiotensinogen mechanism; thus, blood pressure rises when consumed in high amount Geethavani et al. (2014)
It causes heart palpitations or cardiac arrhythmia Baribeau (2014)
Caffeine acutely raises the heart rate as well blood pressure. Hypertensive patients being sensitive to the effects of caffeine must consult doctor regarding their intake Wolde (2014)
4 Withdrawal symptoms Caffeine enhances the feeling of sensation. People feel energetic and consume it more often. So, its withdrawal is associated with headache and fatigue Salin-Pascual et al. (2006), Butt and Sultan(2011)
Its withdrawal is linked to muscle fatigue and allied issues in people addicted to coffee consumption Messina et al. (2015)
Adverse effects such as headache, increased drowsiness, tiredness, anger and fatigue Rogers and Dernoncourt (1998), Wikoff et al. (2017)
Drowsiness, anxiety, irritability, headache and dizziness Higdon and Frei (2006), McIlvain et al. (2011), Baribeau (2014)
5 Anxiety and insomnia Caffeine intake leads to anxiety Rogers and Dernoncourt (1998), Smith, (2002), Seifert et al., (2011)
It acts as a stimulant of CNS. It provokes mental alertness, difficulty in sleeping, prevents deep sleep as well as lowers the capacity to wake up easily. So, it helps to stay awake for longer period Baribeau (2014)
Caffeine helps to increases alertness, reduces fatigue and can elevate mood. Normal consumption of caffeine improves performance on tasks that require alertness, such as simulated driving tasks Rogers and Dernoncourt(1998), Smith (2002)
6 Diabetes Large intake of caffeine (250 mg) after meals by a diabetic person may lead to an increase in blood glucose level Baribeau (2014); Wolde (2014)
7 Bone health Caffeine decreases the calcium absorption in the intestine leading to increased loss of it through urine and stool. It also depletes the amount retained by the bones. Therefore, it may also lead to osteoporosis Heaney(2002), George et al. (2008);Baribeau (2014), Wolde (2014)
A positive association has been found between caffeine consumption and occurrence of fractures Wolde (2014)
8 Gastrointestinal disturbances Caffeine worsens gastro-oesophageal reflux and stomach ulcers by increasing the secretion of gastric acids in the stomach Boekema et al. (1999)
It causes diarrhoea as it relaxes the internal anal sphincter muscles Baribeau (2014)
9 Respiratory health Caffeine increases the respiratory rate by sensitizing the medullary centre to carbon dioxide Benowitz(1990)
10 Reproductive health Caffeine stimulates the central nervous system leading to sleep disruptions in pregnant women. It increases the risk of miscarriages Baribeau (2014)
A positive correlation between maternal caffeine consumption and risk of low birth weight of infants has been found Higdon and Frei (2006), Chen et al. (2014)
11 Nutrient malabsorption Large intake of caffeine consumption may lead to nutrient depletion as well as interfere with nutrient absorption Escott-Stump (2008), Wolde (2014)
Caffeine inhibits Vitamin D receptors and hence its absorption. This could decrease the bone mineral density, causing increased risk of osteoporosis Escott-Stump (2008), Wolde (2014)
It reduces the absorption of iron by 80% causing reduction in red blood cell production Higdon and Frei (2006), Wolde (2014)
Being a mild diuretic, it increases urination. So minerals like calcium, magnesium, zinc, copper, potassium, sodium, phosphate and water soluble vitamins, such as B-vitamins are depleted as a result of fluid loss Escott-Stump (2008), Wolde (2014)
12 Caffeine intoxication Caffeine overdose may lead to agitation, delirium, seizures, dyspnea, cardiac arrhythmia, myoclonus, nausea, vomiting, hyperglycemia and hypokalemia Higdon and Frei (2006)
Affect CV function, other body systems modify behaviour, cause calcium imbalance and even cause Cancer and Death. Caffeine toxicity can result in nervousness, irritability, insomnia, cardiac arrhythmias, increased respiration and headache. In children, it can cause emesis, tachycardia, CNS agitation, GI disturbances and dysfunction related to muscles, liver and renal systems and increased ambulatory blood pressure Akinmolusun et al. (2012)
Caffeine toxicity can cause vomiting, abdominal pain and CNS symptoms like agitation, altered state of consciousness, muscle rigidity at the time of seizures Akinmolusun et al. (2012) Breda et al. (2014)
Common features include nervousness, anxiety, tachycardia, psychomotor agitation and in rare cases, even death Garriott et al. (1985)
Mrvos et al. (1989)
The symptoms of caffeine toxicity can mimic those of anxiety and other mood disorders Greden (1974), Kerrigan and Lindsey (2005), Rath (2012)
Caffeine overdose can cause HTN, palpitations, dieresis, CNS stimulations, nausea, vomiting, marked hypocalcaemia, metabolic acidosis, convulsions, in rare cases even death. In adults, there is also an increased risk of arterial HTN and type 2 Diabetes as high concentration of caffeine reduces insulin sensitivity
Even as little as 50 mg of caffeine can induce tachycardia and agitation. In overdose, caffeine toxicity can mimic amphetamine poisoning and lead to seizures, psychosis, cardiac arrhythmias and potentially but rarely, death
Breda et al. (2014)


Akinmolusun, O. Bezabih, Y. Kaunissaari, S. and Mugambi, A. (2012), “Detrimental effects of energy drink consumption on adolescents”, available at: (accessed 23 May 2017).

Arendash, G.W., Schleif, W., Rezai-Zadeh, K., Jackson, E.K., Zacharia, L.C., Cracchiolo, J.R., Shippy, D. and Tan, J. (2006), “Caffeine protects Alzheimer’s mice against cognitive impairment and reduces brain β-amyloid production”, Neuroscience, Vol. 142 No. 4, pp. 941-952.

Baribeau, H. (2014), “The harmful effects of caffeine on health”, available at: (accessed 23 May 2017).

Barone, J.J. and Roberts, H.R. (1996), “Caffeine consumption”, Food and Chemical Toxicology : An International Journal Published for the British Industrial Biological Research Association, Vol. 34 No. 1, pp. 119-129.

Benowitz, N.L. (1990), “Clinical pharmacology of caffeine”, Annual Review of Medicine, Vol. 41 No. 1, pp. 277-288.

Boekema, P.J., Samsom, M., Berge Henegouwen van, G.P. and Smout, A.J. (1999), “Coffee and gastrointestinal function: facts and fiction: a review”, Scandinavian Journal of Gastroenterology, Vol. 34 No. 230, pp. 35-39.

Breda, J.J., Whiting, S.H., Encarnação, R., Norberg, S., Jones, R., Reinap, M. and Jewell, J. (2014), “Energy drink consumption in Europe: a review of the risks, adverse health effects, and policy options to respond”, Frontiers in Public Health, Vol. 2, p. 134.

Bryan, J. (2008), “Psychological effects of dietary components of tea: caffeine and L-theanine”, Nutrition Reviews, Vol. 66 No. 2, pp. 82-90.

Butt, M.S. and Sultan, M.T. (2011), “Coffee and its consumption: benefits and risks”, Critical Reviews in Food Science and Nutrition, Vol. 51 No. 4, pp. 363-373.

Cadden, I.S.H., Partovi, N. and Yoshida, E.M. (2007), “Possible beneficial effects of coffee on liver disease and function”, Alimentary Pharmacology & Therapeutics, Vol. 26 No. 1, pp. 1-8.

Chen, J.F., Xu, K., Petzer, J.P., Staal, R., Xu, Y.H., Beilstein, M., Sonsalla, P.K., Castagnoli, K., Castagnoli, N. and Schwarzschild, M.A. (2001), “Neuroprotection by caffeine and A2A adenosine receptor inactivation in a model of Parkinson’s disease”, Journal of Neuroscience, Vol. 21 No. 10, pp. RC143-RC143.

Chen, L.W., Wu, Y., Neelakantan, N., Chong, M.F.F., Pan, A. and van Dam, R.M. (2014), “Maternal caffeine intake during pregnancy is associated with risk of low birth weight: a systematic review and dose-response Meta-analysis”, BMC Medicine, Vol. 12 No. 1, p. 174.

Christopher, G., Sutherland, D. and Smith, A. (2005), “Effects of caffeine in non‐withdrawn volunteers”, Human Psychopharmacology: Clinical and Experimental, Vol. 20 No. 1, pp. 47-53.

Davis, J.M., Zhao, Z., Stock, H.S., Mehl, K.A., Buggy, J. and Hand, G.A. (2003), “Central nervous system effects of caffeine and adenosine on fatigue”, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 284 No. 2, pp. R399-R404.

Del Coso, J., Salinero, J.J., González-Millán, C., Abián-Vicén, J. and Pérez-González, B. (2012), “Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures design”, Journal of the International Society of Sports Nutrition, Vol. 9 No. 1, p. 21.

Duncan, M.J., Stanley, M., Parkhouse, N., Cook, K. and Smith, M. (2013), “Acute caffeine ingestion enhances strength performance and reduces perceived exertion and muscle pain perception during resistance exercise”, European Journal of Sport Science, Vol. 13 No. 4, pp. 392-399.

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies) (2015), “Scientific opinion on the safety of caffeine”, EFSA Journal, Vol. 13 No. 5, p. 4102.

Ennis, D. (2014), “The effects of caffeine on health: the benefits outweigh the risks”, Sociological Perspectives.

Escott-Stump, S. (2008), Nutrition and Diagnosis-Related Care, Lippincott Williams and Wilkins, Philadelphia, PA.

Fowler, M.S. and Coutel, F. (2017), “Cocoa beans: from tree to factory”, Beckett’s Industrial Chocolate Manufacture and Use, pp. 9-49.

Franco, R., Oñatibia-Astibia, A. and Martínez-Pinilla, E. (2013), “Health benefits of methylxanthines in cacao and chocolate”, Nutrients, Vol. 5 No. 10, pp. 4159-4173.

Franke, A.G., Lieb, K. and Hildt, E. (2012), “What users think about the differences between caffeine and illicit/prescription stimulants for cognitive enhancement”, PLoS One, Vol. 7 No. 6, p. e40047.

Frary, C.D., Johnson, R.K. and Wang, M.Q. (2005), “Food sources and intakes of caffeine in the diets of persons in the united states”, Journal of the American Dietetic Association, Vol. 105 No. 1, pp. 110-113.

Friberg, E., Orsini, N., Mantzoros, C.S. and Wolk, A. (2009), “Coffee drinking and risk of endometrial cancer-a population‐based cohort study”, International Journal of Cancer, Vol. 125 No. 10, pp. 2413-2417.

Fulgoni, V.L., Keast, D.R. and Lieberman, H.R. (2015), “Trends in intake and sources of caffeine in the diets of US adults: 2001–2010”, The American Journal of Clinical Nutrition, Vol. 101 No. 5, pp. 1081-1087.

Garriott, J.C., Simmons, L.M., Poklis, A. and Mackell, M.A. (1985), “Five cases of fatal overdose from caffeine-containing “look-alike” drugs”, Journal of Analytical Toxicology, Vol. 9 No. 3, pp. 141-143.

Geethavani, G., Rameswarudu, M. and Reddy, R.R. (2014), “Effect of caffeine on heart rate and blood pressure”, International Journal of Scientific and Research Publications, Vol. 4 No. 2, p. 234.

George, S.E., Ramalakshmi, K. and Mohan Rao, L.J. (2008), “A perception on health benefits of coffee”, Critical Reviews in Food Science and Nutrition, Vol. 48 No. 5, pp. 464-486.

Gilbert, R.M., Marshman, J.A., Schwieder, M. and Berg, R. (1976), “Caffeine content of beverages as consumed”, Canadian Medical Association Journal, Vol. 114 No. 3, p. 205.

Giles, G.E., Mahoney, C.R., Brunyé, T.T., Gardony, A.L., Taylor, H.A. and Kanarek, R.B. (2012), “Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose”, Pharmacology Biochemistry and Behavior, Vol. 102 No. 4, pp. 569-577.

Glade, M.J. (2010), “Caffeine–not just a stimulant”, Nutrition (Burbank, Los Angeles County, Calif.), Vol. 26 No. 10, pp. 932-938.

Greden, J.F. (1974), “Anxiety or caffeinism: a diagnostic dilemma”, American Journal of Psychiatry, Vol. 131 No. 10, pp. 1089-1092.

Greenway, F.L. (2001), “The safety and efficacy of pharmaceutical and herbal caffeine and ephedrine use as a weight loss agent”, Obesity Reviews : An Official Journal of the International Association for the Study of Obesity, Vol. 2 No. 3, pp. 199-211.

Greer, F., Hudson, R., Ross, R. and Graham, T. (2001), “Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humans”, Diabetes, Vol. 50 No. 10, pp. 2349-2354.

Harland, B.F. (2000), “Caffeine and nutrition”, Nutrition (Burbank, Los Angeles County, Calif.), Vol. 16 Nos 7/8, pp. 522-526.

Heaney, R.P. (2002), “Effects of caffeine on bone and the calcium economy”, Food and Chemical Toxicology: An International Journal Published for the British Industrial Biological Research Association, Vol. 40 No. 9, pp. 1263-1270.

Heckman, M.A., Weil, J., Mejia, D. and Gonzalez, E. (2010), “Caffeine (1, 3, 7‐trimethylxanthine) in foods: a comprehensive review on consumption, functionality, safety, and regulatory matters”, Journal of Food Science, Vol. 75 No. 3.

Higdon, J.V. and Frei, B. (2006), “Coffee and health: a review of recent human research”, Critical Reviews in Food Science and Nutrition, Vol. 46 No. 2, pp. 101-123.

Higgins, J.P., Tuttle, T.D. and Higgins, C.L. (2010), “Energy beverages: content and safety”, In Mayo Clinic Proceedings, Vol. 85 No. 11, pp. 1033-1041.

Hirose, K., Niwa, Y., Wakai, K., Matsuo, K., Nakanishi, T. and Tajima, K. (2007), “Coffee consumption and the risk of endometrial cancer: Evidence from a case‐control study of female hormone‐related cancers in Japan”, Cancer Science, Vol. 98 No. 3, pp. 411-415.

Johnson-Kozlow, M., Kritz-Silverstein, D., Barrett-Connor, E. and Morton, D. (2002), “Coffee consumption and cognitive function among older adults”, American Journal of Epidemiology, Vol. 156 No. 9, pp. 842-850.

Juliano, L.M., Huntley, E.D., Harrell, P.T. and Westerman, A.T. (2012), “Development of the caffeine withdrawal symptom questionnaire: caffeine withdrawal symptoms cluster into 7 factors”, Drug and Alcohol Dependence, Vol. 124 No. 3, pp. 229-234.

Keijzers, G.B., De Galan, B.E., Tack, C.J. and Smits, P. (2002), “Caffeine can decrease insulin sensitivity in humans”, Diabetes Care, Vol. 25 No. 2, pp. 364-369.

Kempf, K., Herder, C., Erlund, I., Kolb, H., Martin, S., Carstensen, M., Koenig, W., Sundvall, J., Bidel, S., Kuha, S. and Jaakko, T. (2010), “Effects of coffee consumption on subclinical inflammation and other risk factors for type 2 diabetes: a clinical trial”, The American Journal of Clinical Nutrition, Vol. 91 No. 4, pp. 950-957.

Kerrigan, S. and Lindsey, T. (2005), “Fatal caffeine overdose: two case reports”, Forensic Science International, Vol. 153 No. 1, pp. 67-69.

Knight, C.A., Knight, I., Mitchell, D.C. and Zepp, J.E. (2004), “Beverage caffeine intake in US consumers and subpopulations of interest: estimates from the share of intake panel survey”, Food and Chemical Toxicology, Vol. 42 No. 12, pp. 1923-1930.

Komes, D., Horzic, D., Belscak, A., Kovacevic Ganic, K. and Bljak, A. (2009), “Determination of caffeine content in tea and maté tea by using different methods”, Czech Journal of Food Science, Vol. 27, pp. S213-S216.

Kumar, V. and Joshi, V.K. (2016), “Kombucha: technology, microbiology, production, composition and therapeutic value”, International Journal of Food and Fermentation Technology, Vol. 6 No. 1, pp. 13-24.

Kumar, V., Joshi, V.K., Vyas, G., Thakur, N.S. and Sharma, N. (2016), “Process optimization for the preparation of apple tea wine with analysis of its sensory and physico-chemical characteristics and antimicrobial activity against food-borne pathogens”, Nutrafoods, Vol. 15, pp. 111-121.

Lane, J.D. (2011), “Caffeine, glucose metabolism, and type 2 diabetes”, Journal of Caffeine Research, Vol. 1 No. 1, pp. 23-28.

McCusker, R.R., Goldberger, B.A. and Cone, E.J. (2003), “Caffeine content of specialty coffees”, Journal of Analytical Toxicology, Vol. 27 No. 7, pp. 520-522.

McIlvain, G.E., Noland, M.P. and Bickel, R. (2011), “Caffeine consumption patterns and beliefs of college freshmen”, American Journal of Health Education, Vol. 42 No. 4, pp. 235-244.

Mattia, A. (2013), “Regulatory status of caffeine”, available at: (accessed 12 July 2017).

Messina, G., Zannella, C., Monda, V., Dato, A., Liccardo, D., De Blasio, S., Valenzano, A., Moscatelli, F., Messina, A., Cibelli, G. and Monda, M. (2015), “The beneficial effects of coffee in human nutrition”, Biology and Medicine, Vol. 7 No. 4, p. 1.

Morton, J.F. (1992), “Widespread tannin intake via stimulants and masticatories, especially guarana, kola nut, betel vine, and accessories”, Plant Polyphenols, Springer, pp. 739-765.

Mrvos, R.M., Reilly, P.E., Dean, B.S. and Krenzelok, E.P. (1989), “Massive caffeine ingestion resulting in death”, Veterinary and Human Toxicology, Vol. 31 No. 6, pp. pp. 571-572.

Muhammad, S. and Fatima, A. (2014), “Studies on phytochemical evaluation and antibacterial properties of two varieties of Kolanut (Cola Nitida) in Nigeria”, Journal of Biosciences and Medicines, Vol. 02 No. 3, p. 37.

Nehlig, A. (1999), “Are we dependent upon coffee and caffeine? A review on human and animal data”, Neuroscience & Biobehavioral Reviews, Vol. 23 No. 4, pp. 563-576.

Nehlig, A., Daval, J.L. and Debry, G. (1992), “Caffeine and the Central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects”, Brain Research Reviews, Vol. 17 No. 2, pp. 139-170.

Ntiamoah, A. and Afrane, G. (2008), “Environmental impacts of cocoa production and processing in Ghana: life cycle assessment approach”, Journal of Cleaner Production, Vol. 16 No. 16, pp. 1735-1740.

Ogah, C.O. and Obebe, O.T. (2012), “Caffeine content of cocoa and coffee beverages in Lagos, Nigeria”, Journal of Innovative Research in Engineering and Sciences, Vol. 3 No. 1, pp. 404-411.

O’Keefe, J.H., Bhatti, S.K., Patil, H.R., DiNicolantonio, J.J., Lucan, S.C. and Lavie, C.J. (2013), “Effects of habitual coffee consumption on cardiometabolic disease, cardiovascular health, and all-cause mortality”, Journal of the American College of Cardiology, Vol. 62 No. 12, pp. 1043-1051.

Peacock, A., Droste, N., Pennay, A., Miller, P., Lubman, D.I. and Bruno, R. (2016), “Awareness of energy drink intake guidelines and associated consumption practices: a cross-sectional study”, BMC Public Health, Vol. 16 No. 1, p. 6.

Pohlan, H.A.J. and Janssens, M.J. (2010), “Growth and production of coffee”, Soils, Plant Growth and Crop Production, Vol. 3, p. 101.

Pourshahidi, L.K., Navarini, L., Petracco, M. and Strain, J.J. (2016), “A comprehensive overview of the risks and benefits of coffee consumption”, Comprehensive Reviews in Food Science and Food Safety, Vol. 15 No. 4, pp. 671-684.

Prediger, R.D. (2010), “Effects of caffeine in Parkinson’s disease: from neuroprotection to the management of motor and non-motor symptoms”, Journal of Alzheimer’s Disease, Vol. 20 No. 1, pp. S205-S220.

Rath, M. (2012), “Energy drinks: what is all the hype? the dangers of energy drink consumption”, Journal of the American Academy of Nurse Practitioners, Vol. 24 No. 2, pp. 70-76.

Rogers, P.J. and Dernoncourt, C. (1998), “Regular caffeine consumption: a balance of adverse and beneficial effects for mood and psychomotor performance”, Pharmacology Biochemistry and Behavior, Vol. 59 No. 4, pp. 1039-1045.

Rosenbloom, C. (2014), “Energy drinks, caffeine, and athletes”, Nutrition Today, Vol. 49 No. 2, pp. 49-54.

Rosenfeld, L.S., Mihalov, J.J., Carlson, S.J. and Mattia, A. (2014), “Regulatory status of caffeine in the united states”, Nutrition Reviews, Vol. 72 No. 1, pp. 23-33.

Salin-Pascual, R.J., Valencia-Flores, M., Campos, R.M., Castaño, A. and Shiromani, P.J. (2006), “Caffeine challenge in insomniac patients after total sleep deprivation”, Sleep Medicine, Vol. 7 No. 2, pp. 141-145.

Schimpl, F.C., da Silva, J.F., Gonçalves, J.F.D.C. and Mazzafera, P. (2013), “Guarana: revisiting a highly caffeinated plant from the amazon”, Journal of Ethnopharmacology, Vol. 150 No. 1, pp. 14-31.

Seifert, S.M., Schaechter, J.L., Hershorin, E.R. and Lipshultz, S.E. (2011), “Health effects of energy drinks on children, adolescents, and young adults”, Pediatrics, Vol. 127 No. 3, pp. 511-528.

Sengpiel, V., Elind, E., Bacelis, J., Nilsson, S., Grove, J., Myhre, R., Haugen, M., Meltzer, H.M., Alexander, J., Jacobsson, B. and Brantsæter, A.L. (2013), “Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study”, BMC Medicine, Vol. 11 No. 1, p. 42.

Smith, A. (2002), “Effects of caffeine on human behavior”, Food and Chemical Toxicology: An International Journal Published for the British Industrial Biological Research Association, Vol. 40 No. 9, pp. 1243-1255.

Souza, M.A., Mota, B.C., Gerbatin, R.R., Rodrigues, F.S., Castro, M., Fighera, M.R. and Royes, L.F.F. (2013), “Antioxidant activity elicited by low dose of caffeine attenuates pentylenetetrazol-induced seizures and oxidative damage in rats”, Neurochemistry International, Vol. 62 No. 6, pp. 821-830.

Sudano, I., Spieker, L.E., Noll, G., Corti, R., Weber, R. and Lüscher, T.F. (2006), “Cardiovascular disease in HIV infection”, American Heart Journal, Vol. 151 No. 6, pp. 1147-1155.

Van Dam, R.M. (2006), “Coffee and type 2 diabetes: from beans to beta-cells”, Nutrition, Metabolism and Cardiovascular Diseases, Vol. 16 No. 1, pp. 69-77.

Van Dam, R.M. and Feskens, E.J. (2002), “Coffee consumption and risk of type 2 diabetes mellitus”, Lancet (London, England), Vol. 360 No. 9344, pp. 1477-1478.

Van Dam, R.M. and Hu, F.B. (2005), “Coffee consumption and risk of type 2 diabetes: a systematic review”, Jama, Vol. 294 No. 1, pp. 97-104.

Van Dijk, A.E., Olthof, M.R., Meeuse, J.C., Seebus, E., Heine, R.J. and Van Dam, R.M. (2009), “Acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on glucose tolerance”, Diabetes Care, Vol. 32 No. 6, pp. 1023-1025.

Wanyika, H.N., Gatebe, E.G., Gitu, L.M., Ngumba, E.K. and Maritim, C.W. (2010), “Determination of caffeine content of tea and instant coffee brands found in the kenyan market”, African Journal of Food Science, Vol. 4 No. 6, pp. pp. 353-358.

Wikoff, D., Welsh, B.T., Henderson, R., Brorby, G.P., Britt, J., Myers, E., Goldberger, J., Lieberman, H.R., O’Brien, C., Peck, J. and Tenenbein, M. (2017), “Systematic review of the potential adverse effects of caffeine consumption in healthy adults, pregnant women, adolescents, and children”, Food and Chemical Toxicology, Vol. 109 No. 1, pp. 585-648. available at:

Willson, K.C. and Clifford, M.N. (Eds) (2012), Tea: Cultivation to Consumption, Springer Science & Business Media.

Wolde, T. (2014), “Effects of caffeine on health and nutrition: a review”, Food Science and Quality Management, Vol. 30, pp. 59-65.

Yenisetti, S.C. and Muralidhara (2016), “Beneficial role of coffee and caffeine in neurodegenerative diseases: a minireview”, AIMS Public Health, Vol. 3 No. 2, pp. pp. 407-422.

Zoumas, B.L., Kreiser, W.R. and MARTIN, R. (1980), “Theobromine and caffeine content of chocolate products”, Journal of Food Science, Vol. 45 No. 2, pp. 314-316.

Further reading

Gerald, I., Arthur, D.E. and Adedayo, A. (2014), “Determination of caffeine in beverages: a review”, American Journal of Engineering Research (AJER), Vol. 3 No. 8, pp. 124-137.

Lugasi, A., Bakacs, M. and Martos, É. (2015), “Caffeine intake in Hungary–a population based estimation”, Acta Alimentaria, Vol. 44 No. 2, pp. 242-250.


Conflicts of interest: All authors have no conflicts of interest to declare.

Corresponding author

Vikas Kumar can be contacted at: