Latin name: Coffea spp.
Common names: Coffee
C. arabica – Arabica or Arabian coffee
C. canephora – Robusta or Congo coffee
C. liberica – Liberian coffee
A food, which may result in allergy symptoms in sensitised individuals.
Coffee was originally consumed in ancient Abyssinia. Cultivated by the Arabs since 600 AD, coffee is now used throughout the world.
Coffee comes from an evergreen, glabrous shrub or small tree, up to 5m tall if left un-pruned. It is widely grown in the warmer, more moist and mountainous regions of the world. Dried seeds or ‘beans’ are roasted, ground, and brewed to make one of the two most important beverages in the Western world. Instant coffee is the dried extract of roasted, ground coffee.
Coffea arabica (mild, refined, fragrant) accounts for 60% of the world's production and Coffea robusta (strong, full-bodied, higher caffeine) for 30%. Despite its name, C. arabica originated in Ethiopia, where it grows at elevations between 1 375 and 1 830m. From Arabia, cultivation spread throughout the West Indies and Central America, and favourable regions of South America. Later, the plant reached India and Sri Lanka.
In most places brewed coffee is preferred, but instant coffee is commonly used for convenience. (Additives and coffee substitutes or extenders include roasted chicory, chickpea, cereals, fruits and vegetables. These may be added in the manufacturing of some instant coffees.) Decaffeinated coffee of both kinds is also popular. In their native Ethiopia, beans have been used as a masticatory since ancient times, and are also cooked in butter to make rich flat cakes. In Arabia a fermented drink made from the pulp is consumed. Coffee is widely used as a flavouring, particularly in ice cream, pastries, candies, and liqueurs. The caffeine from coffee is commonly extracted and put to a variety of uses (see below).
Coffee contains over 200 substances, including caffeine, liverine, methylliberine, paraxanthine, theacrine, theobromine, theophylline, acids (chlorgenic, acetic, citric, formic, fumaric, lactic, malic, oxalic, quinic, quinides), carbohydrates (arabinose, fructose, galactose, glucose, inositol, mannitol, mannose, sucrose, xylose), lipids, minerals, and bases (betaine, choline, niacin, trigonelline). (1)
Caffeine tends to expand blood vessels so that more blood flows, and also acts on the central nervous system, kidneys, heart, and muscles. It has many medicinal and folk-medicinal uses.
Coffee pulp and parchment are used as manures and mulches, and in India they are occasionally fed to cattle. Coffelite, a type of plastic, is made from coffee beans. The wood of the coffee tree is hard, dense and durable, is good for polishing, and is suitable for tables, chairs, and turnery. Coffee with iodine is used as a deodorant. Caffeine has been described as a natural herbicide. It is a common additive in over-the-counter diet pills, painkillers, and stimulants.
Coffee allergens resulting in occupational allergy (asthma, allergic rhinitis and allergic conjunctivitis) have been described. See Green Coffee bean k70.
No allergens resulting in food-allergic reactions have been described to date.
In a study of occupational asthma caused by roasted coffee, immunologic evidence has been suggested that roasted coffee contains the same antigens as green coffee, but at a lower concentration. Although nine to 10 protein bands of 15 to 60 kDa were identified for the green coffee bean extract, only one band of approximately 43 kDa was present in the roasted coffee bean extract, and was shown to be a major band in the green coffee bean extract as well. (2)
No cross-reactivity to coffee allergens has been documented to date. However, adverse reactions to additives present in coffee, and also present in another food, may result in an impression that this has occurred.
a. IgE-mediated reactions
See Green Coffee bean k70 for adverse effects from the manufacture or handling of green coffee bean, which may result in symptoms of occupational asthma, rhinitis and conjunctivitis.
Allergic reactions to ingestion of coffee are uncommon. Clinical reactions may be difficult to differentiate from those caused by caffeine or other additives. (3, 4, 5, 6, 7) Instant coffee may have additives and coffee substitutes added, e.g. roasted chicory, chickpea, cereal, fruits and vegetables.
An early article reported that skin reactions had been described. (3, 4) The article described a patient who claimed to always experience diarrhoea after drinking a cup of coffee. Anecdotal reports of coffee being responsible for migraine, asthma, gastro-intestinal complaints, cutaneous and other manifestations have not been verified. The article references an earlier article that described itching, urticaria, angioneurotic oedema, intestinal spasms, diarrhoea, and rhinopathy resulting from Coffee. (3, 8)
A study was conducted at 17 clinics in 15 European cities to evaluate the differences between some Northern countries regarding what foods (according to the patients) elicit hypersensitivity symptoms. The informants were food-allergic individuals responding to questionnaires concerning 86 different foods. It was reported that the foods eliciting symptoms in Russia, Estonia, and Lithuania were mainly citrus fruits, chocolate, honey, apple, hazelnut, strawberry, fish, tomato, egg, and milk, which differed from the situation in Sweden and Denmark, where Birch pollen-related foods such as nuts, apple, pear, kiwi, stone fruits and carrot were the most common reported causes.
The most common symptoms reported were oral allergy syndrome and urticaria. Birch pollen-related foods dominate in Scandinavia, whereas some mugwort-related foods were of more importance in Russia and the Baltic states. Among 1 139 individuals, coffee was the 40th-most-reported culprit food, resulting in adverse effects in 13% of the group. (9) In an Indian study of 24 children aged 3 to 15 years, with documented deterioration in control of their perennial asthma, serum-specific IgE to coffee was found in 2 (8%). (10)
In an early paper on adverse effects of coffee, four of five cases reported were said to represent true allergic manifestations to coffee. The first patient reported severe migraine following coffee ingestion; the second complained of gastroenteritis and headache, occurring only during the pollen season; a third described gastroenteritis, malaise, headache, and allergic rhinitis; and the fourth complained of widespread urticaria. (3)
Intra-dermal skin testing was performed on patient 1, which resulted in symptoms of increased pulse rate, lassitude and weakness, extreme nausea, and a drop in blood pressure, followed by the development of severe migraine. The symptoms other than the migraine and gastroenteritis were relieved by epinephrine. Her skin tests to coffee were markedly positive. Oral challenge was positive within 5 minutes. (3)
Patient 2 was a woman who complained of gastroenteritis and headache, occurring only during the ragweed pollination period. She was able to drink five cups of coffee daily at any time of the year other than the ragweed season, but ingesting even half a cup of coffee at this time would induce a severe headache and abdominal cramps, followed by diarrhoea. An intra-dermal test tor coffee was markedly positive. (3)
Patient 3 described allergic rhinitis based on sensitivity to multiple foods, and examination found evidence of allergic rhinitis. Skin-prick tests were positive for tomato, cocoa, clam, spinach, banana, canteloupe, strawberry and wheat. Resolution of her allergic rhinitis occurred following elimination of these foods. However, she noted that when she drank coffee, her symptoms recurred. Skin-prick tests were negative for coffee, but oral challenge with coffee masked in gelatine capsules resulted in a reproduction of all of her symptoms. (3)
Patient 4, a male, reported urticaria following ingestion of coffee. Skin tests were positive for coffee, wheat and rye. Within one hour after ingesting coffee he experienced marked generalised urticaria, including on the face. However, an oral challenge test was negative. (3)
Adverse reactions in patient 5 were attributed to possible caffeine intolerance: the woman had previously stopped drinking coffee as a result of experiencing fatigue and palpitations of the heart following ingestion of coffee. She had begun to drink coffee in the afternoon, but immediately experienced her chronic constipation relieved by a loose, watery stool. (3)
A 45-year-old woman developed chronic urticaria and anaphylactoid reactions after ingesting coffee and taking an analgesic drug. According to the authors, there was conclusive evidence (using prick tests and oral provocation tests, among others) that anaphylactic hypersensitivity to coffee co-existed with idiosyncratic reaction to acetylsalicylic acid, indomethacne, metamizole (dipyrone), and caffeine. (11)
A 39-year-old woman who had been working in a coffee bar for 12 years reported chronic hand dermatitis: erythema, scaling and fissuring on the palms, fingertips and lateral aspects of the 1st, 2nd and 3rd fingers of both hands. When she prepared espresso coffee her symptoms worsened, following each contact with roasted coffee powder and coffee drink. Patch tests with roasted coffee powder and coffee drink were both positive. Prick tests with coffee extract showed weak positivity. Scratch tests with roasted coffee powder were negative, as were open patch tests on previously-affected hand skin. (12)
A 55-year-old Italian man and his 22-year-old daughter experienced the onset of food allergy to coffee occurring after a helminth infection (Clonorchis sinensis) contracted in China. During a nine-hour wait at the airport on return, they drank a large quantity of coffee without ingestion of any other food. A few days later they developed abdominal pain, diarrhoea and urticaria that worsened daily. Itching remitted with oral antihistamines but diarrhoea continued for months, until endoscopy and biopsy revealed the presence of Clonorchis sinensis. Two months after mebendazole therapy, blood eosinophils and serum ECP remained elevated. Importantly, they reported that diarrhoea and urticaria were more evident after meals; in particular after breakfast, when they usually drank only coffee. Elimination of coffee resulted in the urticaria and diarrhoea resolving completely. Three successive coffee challenges consistently induced immediate symptoms. Skin-prick testing for coffee was positive, and coffee-specific serum IgE was 4.8 and 5.9 kU/L. After coffee was eliminated, the symptoms disappeared, but skin-prick tests remained positive. The authors hypothesised that the helminth infection had facilitated the new onset of food allergy to coffee. (13)
A study described a male who experienced 4 allergic incidents after drinking coffee. Sensitisation to coffee and to the gum arabic coating of roasted coffee beans was demonstrated by skin-specific IgE tests and by basophil degranulation tests. (7)
b. Other reactions
The consumption of coffee can have diverse non-allergy effects, especially diverse where the increase of ventilatory frequency is concerned. The effect on bronchospasm may be beneficial. But coffee has been suspected of contributing to the development of chronic airflow obstruction (COPD) and bronchial cancer. If coffee is taken in large quantities by pregnant women, there is an increased risk of neonatal apnoea in the newborn. (14)
In Japanese adult patients with atopic dermatitis who showed unpredictable, irregular aggravation of skin lesions, coffee was reported to be one of various foods that play an unpredictable role in the irregular worsening of atopic dermatitis. The patients were hospitalised and openly challenged with suspected foods. Exclusion of the offending foods for 3 months brought about a progressive improvement in the patients’ health. (15) Nail-fold contact dermatitis from coffee powder was described in a 40-year-old woman who presented with a 1-year history of a chronic paronychia involving the left thumb. The patient prepared a large number of cups of coffee daily. The on–off button of the coffee maker was located below the powdered coffee reservoir. When she pushed the button with her left thumb, it became dusted with coffee powder falling from above. The severity of her paronychia tended to improve during holidays. Patch testing to coffee powder was positive. (16)
Mucosal lesions in the mouth (contact dermatitis) and flatulence as a result of drinking 'instant' coffee were reported in a 47-year-old woman who developed recurrent episodes of inflammation of her oral mucosa with occasional vesicle formation, particularly on the gums between the teeth. There was very little itching, although a burning sensation was frequently present. Her only other symptom was flatulence, which had troubled her excessively for a few months. Keeping a food diary established that she was allergic to instant coffee, and exclusion of instant coffee led to a dramatic improvement. Patch testing with various preparations of instant coffee was positive. (17)
Cheilitis due to coffee ingestion has been reported. (18) Eosinophilic cystitis attributed to drinking coffee has also been reported. (19)
Both regular and decaffeinated coffees have a cholinomimetic action, distinct from any effect of caffeine, and reversible by atropine. The bioactive fraction was purified from instant decaffeinated coffee. Extracts of green coffee beans and roasted ground coffees showed that the cardioactive compound was present only in roasted coffees. Similar analyses of other commonly consumed beverages, including teas and cocoa, showed that this compound was not present in beverages other than coffee. (20) As a result of the caffeine in coffee a number of adverse effects may occur, including migraine, urticaria and anaphylaxis. (21, 22, 23)
The mechanism underlying coffee-induced heartburn and dyspepsia remains poorly understood. This has led to speculation that variations in coffee processing may be important. In a study to determine whether a coffee brewed with coffee beans processed using conduction roasting would result in fewer symptoms of gastro-oesophageal reflux and dyspepsia in coffee-sensitive individuals compared to a differently-processed yet otherwise similar coffee, consumption of coffee by 30 coffee-sensitive individuals resulted in heartburn, regurgitation, and dyspepsia in most individuals, for both types of coffee. No significant differences were demonstrated in the frequency or severity of heartburn, regurgitation or dyspepsia between the two coffees, either in the fasting state or after the test meal. (24)
This study confirms the findings of an earlier study in which coffee was shown to play a role in gastro-oesophageal reflux, in particular in coffee-sensitive individuals. Gastro-oesophageal reflux and symptoms of coffee sensitivity increased with the concomitant ingestion of food. Symptoms of dyspepsia appeared to be influenced by variations in both the coffee itself and in the characteristics of susceptible individuals. (25) Reflux oesophagitis has been described previously. (26)
Occupational asthma caused by Chrysonilia sitophila (asexual state of Neurospora sitophila) was described in a 43-year-old man, who experienced repetitive episodes of coughing, dyspnoea, rhinitis, and conjunctivitis related to his job, which consisted of emptying containers of coffee grounds and placing new powdered coffee into beverage dispensers. The coffee grounds were covered with an orange powder, which dispersed into the air when he cleaned the machine. The orange powder grew C. sitophila. Skin-prick test with the coffee grounds covered by the orange powder was positive, but negative for fresh coffee powder. Peak expiratory flow rate (PEFR) showed a decrease of greater than 20% during his occupational activity. Streptavidin ImmunoCAP (®) coupled to C. sitophila was 11.4 kU/liter. Specific IgE values for coffee and green coffee bean were negative. (27) A similar case was described in a 29-year-old working as a service operator of coffee dispensers. (28)
See Green Coffee bean k70 for adverse effects from the manufacture or handling of green coffee bean, which may result in symptoms of occupational asthma, rhinitis and conjunctivitis.
Compiled by Dr Harris Steinman.
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- Ciprandi G, Cavallucci E, Cuccurullo F, Gioacchino MD. Helminthic infection as a factor in new-onset coffee allergy in a father and daughter. J Allergy Clin Immunol 2008;121(3):773-4.
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- DiBaise JK. A randomized, double-blind comparison of two different coffee-roasting processes on development of heartburn and dyspepsia in coffee-sensitive individuals. Dig Dis Sci 2003;48(4):652-6.
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- Heffler E, Nebiolo F, Pizzimenti S, Ferlini M, Marchese C, Rolla G. Occupational asthma caused by Neurospora sitophila sensitization in a coffee dispenser service operator. Ann Allergy Asthma Immunol 2009;102(2):168-9.