Number 144 March 1998 ( Number 103 revised)
MAFF UK - SURVEY OF CAFFEINE AND OTHER METHYLXANTHINES IN ENERGY DRINKS AND
OTHER CAFFEINE-CONTAINING PRODUCTS (UPDATED)
Index to MAFF UK Food Surveillance Information
21: MAFF UK -
Caffeine in Guarana Products (December 1993)
103: MAFF UK - Survey of Caffeine and
Other Methylxanthines in Energy Drinks and Other Caffeine-Containing Products
MAFF completed a survey of caffeine and two other methylxanthines
(theobromine and theophylline) in a range of "energy" drinks and other
soft drinks, teas, coffees and chocolate products in early 1997. The results of
this survey were originally published in Food Surveillance Information Sheet
103 in March 1997. This revised
information sheet provides additional results for chocolate bars which have
recently been obtained and includes comments from the UK tea and coffee trade (Annex C). It replaces the previous Information Sheet.
Caffeine levels in standard (non-decaffeinated) cola drinks ranged from 33
to 213 mg/l, while those in low-caffeine colas were not detectable (less than
0.2 mg/l). Energy drinks had a broad range of caffeine contents (0.5-349 mg/l),
but most contained more than 110 mg/l. As expected, a wide range of caffeine
concentrations was found in the tea and coffee products analysed. Caffeine
concentrations in standard tea products ranged from 95 to 430 mg/l, while those
in standard instant and ground coffee ranged from 105 to 340 mg/l, when prepared
according to a standard method. Variable consumer preparation methods would
further broaden the range of caffeine concentrations to which consumers could be
exposed. As expected, the two decaffeinated instant coffees analysed contained
low levels of caffeine (10 and 11 mg/l) and complied with the relevant statutory
limits. Levels of caffeine in chocolate products ranged between 5.5 and 710
mg/kg, with the highest levels being found in chocolate bars. Theobromine
levels were low, with the exception of chocolate products, while theophylline
was undetectable in most products.
Caffeine (1,3,7-trimethylxanthine) is one of a group of chemicals called
methylxanthines which occur naturally in a range of plant-derived foodstuffs
such as coffee, tea, cocoa/chocolate and cola products. Caffeine also occurs in
soft drinks due to the addition of flavourings containing natural extracts such
as cola nut which may contain caffeine and, more frequently, due to the addition
of caffeine as such. Although there is no statutory limit for caffeine in soft
drinks, its use is subject to the general provisions of the Food Safety Act
A number of studies have been carried out to determine the levels of
caffeine in coffee, tea, chocolate products and soft drinks.2-16 However, details of the products analysed and the
sample weights used in their preparation have often not been reported, thus
limiting a comparative evaluation of the data and their usefulness. Moreover,
as these studies were generally undertaken over five years ago and most were
carried out in the USA, they do not provide an up-to-date picture of the
caffeine content of products currently sold in the UK.
In addition to the more traditional caffeine-containing soft drinks such as
colas, a new range of drinks, known as "energy" drinks, which are
frequently marketed as "revitalising", "stimulating" or
providing some sort of "pick-me-up", has entered the market over the
last few years. Some of these contain extracts of guarana (Paullinia cupana),
a South American plant which has been shown to contain caffeine,16 and many have caffeine added as such. These
products typically contain caffeine at higher levels than cola drinks, with
concentrations of up to 350 mg/l being reported on the labels of some canned
drinks. However, as the majority of these drinks were not available until
relatively recently, there is a lack of data on their caffeine content.
MAFF has carried out a survey to provide a reliable quantitative assessment
of the caffeine content of a wide range of soft drinks, including energy drinks,
and other caffeine-containing products currently available to consumers in the
UK. Products have also been analysed for two other methylxanthines, theobromine
(3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine), which are often
found along with caffeine and for which data in the scientific literature are
generally lacking. The information obtained will expand and update the data
generated by MAFF on the composition of food in the UK and may be used to
estimate dietary intakes of caffeine. In addition, data obtained on the
caffeine levels of energy drinks will not only be used to inform any future EC
discussions on these products, but will also assist the European Commission's
Scientific Committee for Food (SCF) in its on-going review of these drinks.
A total of 162 samples, comprising 36 cola drinks, 26 energy drinks, 12
miscellaneous drinks (mainly soft drinks), 26 tea products (mainly loose, bags
and instant), 30 coffees (mainly percolated, filter and instant) and 32
chocolate products (comprising powdered and ready-to-drink milk drinks,
chocolate mousses and chocolate bars), were obtained for analysis by MAFF
Central Science Laboratory (CSL) Food Science Laboratory, Norwich, between June
and December 1996. The majority of these were purchased from retail outlets in
and around London, although a small number of energy drinks not available in the
UK at the time were obtained direct from the manufacturers. Details of the
ingredients listed on the product label and, where appropriate, manufacturers'
instructions for preparation, were recorded on receipt.
Tea and coffee infusions were prepared according to a standard method
involving 200 ml of boiling water and either: 1.6 g of loose tea (consistent
with the use of 1 teaspoonful by Scott et al.9)
or instant coffee (consistent with Scott et al.9),
2.6 g of filtered or percolated coffee (equivalent to a level dessertspoonful
(10 ml)); or one tea bag. Instant tea was also prepared using 1.6 g of powder,
but the results are expressed in terms of the average portion size on the label.
Loose and bagged teas were allowed to brew for 5 minutes without stirring,
while percolated coffees were prepared by refluxing the coffee under simulated
percolator conditions for 10 minutes. Filter coffees were prepared using a
domestic coffee filter apparatus. Powdered chocolate drinks were prepared using
a reduced sample weight (1 g) in 200 ml of boiling water in order to maintain
product solubility on cooling, with the results subsequently being expressed in
terms of the portion size recommended on the packet.
All samples were analysed for caffeine, theophylline and theobromine using
liquid chromatography with ultraviolet detection (LC-UV), with
beta-hydroxyethyltheophylline as an internal standard. Confirmation
by liquid chromatography-mass spectrometry (LC-MS) was carried out in cases
where peak purity data were outside the quality control limits of 95 per cent
purity. Further details of the methods used are given elsewhere.17
Samples were analysed using a batch procedure, with each batch typically
comprising 8 test samples, together with 4 quality control samples (an in-house
reference material, a duplicate test sample, a spiked sample and a blank) to
determine accuracy and precision. In-house reference materials were chosen to
matrix-match the respective sample types as closely as possible. In batches of
colas, energy and miscellaneous drinks, a cola drink, which had previously been
analysed as part of the Food Analysis Performance Assessment Scheme (FAPAS) and
which had an assigned value of 104.4 mg/l for caffeine,18
was included. Batches of teas and coffees contained an instant tea material and
batches of chocolate products, apart from the chocolate bars, contained a
chocolate powder material, with both reference materials having been tested for
homogeneity prior to the start of the survey. Spiked samples were fortified at
levels similar to those already present in the products.
Between-batch analyses of the in-house reference materials and other control
samples showed excellent agreement, being well within the specified acceptance
criteria. For example, precision values for replicates of the test samples and
in-house reference materials were well within 15 per cent of the mean value and
recoveries of the internal standard and spiked samples all met the acceptance
criterion of greater than 70 per cent, with most being above 90 per cent.
Caffeine concentrations obtained for the cola reference material (mean, 105.9
mg/l; standard deviation, 2.8 mg/l; n=12) were also very close to the FAPAS
assigned value of 104.4 mg/l. The survey results were calculated relative to a
recovery of 100 per cent for the internal standard, with no other recovery
adjustment being made as the recoveries of the methylxanthines relative to the
internal standard were close to unity.
Limits of detection of 0.2 mg/l for caffeine and 0.1 mg/l for theobromine
and theophylline were obtained for colas, energy drinks, teas, coffees and
chocolate infusions, while for chocolate milk drinks, the corresponding
detection limits were 1 mg/l and 0.5 mg/l, respectively. Limits of 2 mg/kg for
caffeine and 1 mg/kg for theobromine and theophylline were obtained for the
chocolate mousse samples. For the chocolate bars, the limits of detection for
caffeine, theobromine and theophylline were 50 mg/kg, 20 mg/kg and 30 mg/kg,
A summary of the concentrations of caffeine, theobromine and theophylline
found in the cola, energy and other miscellaneous drinks is given in
Table 1, with the results for teas being summarised in
Table 2, coffees in Table 3
and chocolate products in Table 4. Individual results
for each product are listed in Annex A.
Annex B summarises the levels of caffeine in tea and
coffee products reported in the scientific literature.
Annex C summarises and discusses comments received
from the UK tea and coffee trade.
As shown in Table 1, caffeine concentrations in
the 32 samples of standard (diet and regular (non-diet)) cola ranged from 33 to
213 mg/l (mean, 69 mg/l) and are similar to those reported previously by other
workers such as Galasko
et al.8 (27-146 mg/l), Scott et al.9 (50-90 mg/l) and Sanchez
et al.10 (58-147 mg/l). It is
interesting to note that in both diet and regular drinks, levels appeared to
fall into three distinct sub-ranges, at around 35 mg/l, 75 mg/l and greater than
100 mg/l, perhaps reflecting the different flavouring blends available to
manufacturers. In contrast to the standard cola drinks, caffeine was not
detected (less than 0.2 mg/l) in the four colas labelled as caffeine-free or
decaffeinated or not listing caffeine on the label. Theobromine and
theophylline levels were generally below the limit of detection of 0.1 mg/l in
both caffeinated and decaffeinated products.
Caffeine concentrations in the 26 energy drinks analysed ranged from 0.5 to
349 mg/l (mean, 240; median, 293 mg/l) (Table 1), with
all but one sample containing over 110 mg/l and most having significantly higher
levels than cola drinks. Caffeine concentrations found in individual products
(such as Red Bull, Virgin Energy, XTC and X-Plosiv) are similar to those
and, where given, to those stated on the can label (see
Annex A). Caffeine levels in drinks containing guarana
extract but with no added caffeine (range, 167-188 mg/l) are also similar to
those reported in an earlier survey of these products.16
Lower levels of theobromine (less than 0.1-6.2 mg/l) and theophylline (less
than 0.1-1.3 mg/l) compared to caffeine were found in energy drinks.
Table 1 also includes data for 12 miscellaneous
drinks, comprising two alcoholic drinks and 10 assorted soft drinks. Caffeine
concentrations ranged widely (less than 0.2-123 mg/l), with the highest levels
being found in the diet and regular varieties of Mountain Dew, a
citrus-flavoured drink. Bunker and McWilliams4
reported a similar caffeine concentration (152 mg/l) for this product, while in
a later survey by Galasko
et al.,8 caffeine was not detected.
Detectable concentrations of theophylline (1.2 and 1.4 mg/l) were found only in
these two products, while none of the samples contained detectable levels of
theobromine (less than 0.1 mg/l).
A summary of the levels of caffeine, theobromine and theophylline in the 26
tea products analysed is given in Table 2a. Caffeine
concentrations in tea infusions made from 14 standard (non-decaffeinated) bags
ranged from 245 to 430 mg/l (mean, 326 mg/l) and are similar to those reported
previously4,6,9,11 (Table B1, Annex B).
Theobromine levels were lower at 10-31 mg/l (mean, 22 mg/l), also consistent
with previous reports.6,9
Theophylline levels in these products were generally low, at up to 2 mg/l.
(Comments from UK Tea Trade Technical Committee (UKTTTC) on these results are
The caffeine levels in infusions made from three loose leaf teas ranged from
95 to 105 mg/l (mean 102 mg/l) and are similar to some,4,11 but lower than other8,9 results in the scientific literature (Table B1, Annex B). This difference may reflect the
variations in the water:tea ratios used to prepare the infusions, since the
amount of caffeine extracted per gram of tea (11.5-12.8 mg (Table 2b)) is within the previously reported
range of 5-30 mg (Table B1, Annex B) and agrees closely
with two of the three published studies4,11 with which direct comparisons can be made. The
caffeine results obtained in the survey are, however, lower than those
subsequently reported by the UKTTTC for the same products (Annex
C). Theobromine and theophylline levels in the three survey samples were
low, at 6-7 mg/l and 0.3-0.5 mg/l, respectively.
After adjusting for portion size (see Table A4), the
caffeine concentrations in the three instant tea infusions were in the range,
175-197 mg/l (mean, 183 mg/l), while theobromine levels ranged from 8.1 to 10.3
mg/l (mean, 9.6 mg/l) and theophylline levels were 0.8-1.1 mg/l. Similar levels
of caffeine were also reported by Blauch and Tarka,6
although Reid and Good5 found a slightly lower
concentration (Annex B).
As expected, caffeine concentrations in infusions made from the two samples
of decaffeinated tea bags were very low, at 5 mg/l and 20 mg/l (Table 2a and Annex A). A caffeine
content of 125 mg/l was found in the one "low caffeine" product
analysed which, in terms of dry tea (8.2 mg/g), is around 40 per cent of that
found in normal tea bags (mean, 22 mg/g). Despite this, these tea bags met the
manufacturer's claim of containing half the caffeine of its normal bags (17.2
mg/g). The levels of theobromine and theophylline in the decaffeinated and low
caffeine products were of the same order as those in the standard bagged teas
(15.0-26.5 mg/l and 1.0-1.5 mg/l, respectively).
Levels of caffeine, theobromine and theophylline in the 30 coffee products
analysed are summarised in Table 3. As shown,
caffeine levels of 210-340 mg/l (mean, 288 mg/l) were found in the 16 standard
instant coffees analysed, similar to those reported previously4-6,9,11 (Table B2, Annex B). The two decaffeinated instant coffees
analysed contained, as expected, very low levels of caffeine, at 10 and 11 mg/l.
As in the case of the teas, levels of theobromine and theophylline in standard
and decaffeinated instant coffees were similar.
Caffeine concentrations found in filter and percolated coffee infusions
(range, 105-215 mg/l; mean, 180 mg/l) (Table 3) are
similar to the levels reported previously by Reid and Good,5
Blauch and Tarka6 and Stavric et al.11 but are significantly lower than those found by
Scott et al.9 As with the instant
coffees, levels of theophylline and theobromine in the filter and percolated
coffees were low. These drinks were prepared using 2.6 g of coffee, equivalent
to a dessertspoonful, the portion size per cup recommended on the majority of
the product labels as purchased. According to the UK coffee trade, 2.6 g is
lower than that used by most consumers who typically use between 3 and 15 g
(mean, 7.6 g) per 200 ml cup (see
Annex C for further details).
Caffeine levels in the four miscellaneous coffee products ranged from 70 to
580 mg/l (Table 3), with the highest levels being
found in an instant espresso product and a coffee and chocolate powdered drink.
The concentration of theobromine in the latter sample was also significantly
higher than in other coffee infusions, at 60 mg/l, due to the presence of
chocolate in the product.
Levels of caffeine, theobromine and theophylline in the 32 chocolate
products analysed (powdered and milk drinks, mousses and chocolate bars) are
summarised in Table 4. In the case of the powdered
drinks, as noted previously, determinations were carried out using a sample
weight of 1 g due to solubility problems on cooling. However, the
concentrations reported in Table 4 are expressed in
terms of the portion size recommended on the packet. As shown, the
concentrations of caffeine in the 18 powdered drinks analysed ranged from 5.5 to
41 mg/l. Previous studies6,9
have found similar results for chocolate drinks and hot cocoa mixes. Higher
theobromine concentrations compared to caffeine (range, 85-590 mg/l; mean, 367
mg/l) were found in the powdered drinks which are similar to those previously
reported.6 Theophylline levels ranged up to 8
mg/l (mean, 2.9 mg/l; median, 2.5 mg/l).
Table 4 shows that caffeine concentrations in the
six chocolate milk drinks ranged from 8 to 20 mg/l, while theobromine levels
ranged from 141 to 371 mg/l. The two chocolate mousses had caffeine
concentrations of 21 and 50 mg/kg and theobromine contents of 386 and 651 mg/kg.
Theophylline was undetectable in the milk drinks and mousses.
Caffeine levels in five of the six chocolate bars ranged from 110 to 340
mg/kg, while the levels of theobromine in these products ranged from 1300 to
4740 mg/kg. Theophylline was not detectable. These concentrations are within
the broad range of levels reported in the scientific literature (100-1200 mg/kg
and 1300-7000 mg/kg for caffeine and theobromine, respectively).7,12-14 The remaining product was
atypical, having a higher cocoa content (70 per cent cocoa beans) than the other
chocolate bars and, consequently, higher caffeine and theobromine concentrations
(710 and 10370 mg/kg, respectively). The wide range of theobromine levels found
in chocolate products is thought to reflect the variable concentrations found in
cocoa beans12,20 which
are affected by factors such as the origin, degree of maturity at harvest and
As stated earlier, comparison of analytical data on caffeine levels in
various foods and beverages reported by different authors is not always
straightforward. There are many variables to consider including the sample
weight and the volume of water used in preparing some drinks, brewing time (tea)
and also different methods of detection, possible changes in drink formulations
by manufacturers over the years and use of different formulations to appeal to
consumers in different countries. Despite this, the levels of caffeine,
theobromine and theophylline found in this survey are generally consistent with
The Coffee and Coffee Products (Amendment) Regulations 198722 state that the caffeine content of decaffeinated
instant coffee products should not exceed 0.3 per cent of dry coffee matter
determined using the method of analysis laid down in Commission Directive
79/1066/EEC.23 The two decaffeinated instant
coffees analysed were found to comply with these Regulations, having caffeine
concentrations equivalent to around 0.1 per cent in the coffee powder. There
are no regulations on decaffeinated tea products.
The information obtained in the survey will expand and update the data
generated by MAFF on the composition of food in the UK and may be used to
estimate dietary intakes of caffeine. In addition, data obtained on caffeine in
energy drinks will be used to inform any future EC discussions on these products
and will assist the SCF in its on-going review of these drinks.
- Food Safety Act 1990. HMSO.
- Gilbert, R.M., Marshman, J.A., Schweider, M. and Berg, R.
(1976). Caffeine content of beverages as consumed. Canadian Medical
Association Journal, 114, 205-211.
- Groisser, D.S. (1978). A study of caffeine in tea. American
Journal of Clinical Nutrition, 31, 1727-1732.
- Bunker, M.L. and McWilliams, M. (1979). Caffeine content
of common beverages. Journal of American Dietetic Association, 74,
- Reid, S.J. and Good, T.J. (1982). Use of chromatographic
mode sequencing for sample preparation in the analysis of caffeine and
theobromine from beverages. Journal of Agricultural Food Chemistry,
- Blauch, J.L. and Tarka, Jr., S.M. (1983). HPLC
determination of caffeine and throbromine in coffee, tea and instant hot cocoa
mixes. Journal of Food Science, 48, 745-750.
- Terada, H. and Sakabe, Y. (1984). High-performance liquid
chromatographic determination of theobromine, theophylline and caffeine in food
products. Journal of Chromatography, 291, 453-459.
- Galasko, G.T.F., Furman, K.I. and Alberts, E. (1989). The
caffeine contents of non-alcoholic beverages. Fd Chem. Toxic., 27,
- Scott, N.R., Chakraborty, J. and Marks, V. (1989).
Caffeine consumption in the United Kingdom: a restrospective survey. Food
Science and Nutrition,
- Sanchez, S., Bodart, P. and Noirfalise, A. (1996). Taux
de caféine dans des boissons non-alcooliseés. Cerevisia,
- Stavric, B., Klassen, R., Watkinson, B., Karpinski, K.,
Stapley, R. and Fried, P. (1988). Variability in caffeine consumption from
coffee and tea: possible significance for epidemiological studies. Fd Chem.
26 (2), 111-118.
- Zoumas, B.L., Kreiser, W.R. and Martin, R. A. (1980).
Theobromine and caffeine content of chocolate products. Journal of Food
Science, 45, 314-316.
- Kirk, R.S. and Sawyer, R. (1991). Pearson's
Composition and Analysis of Foods. 9th Edition. Longman Scientific and
Technical, Harlow, Essex.
- Love, J.L. Caffeine, theophylline and theobromine in New
Food Technology in New Zealand, January 1989, 29-31.
- Bell, L.N., Wetzel, C.R., Grand, A.N. (1996). Caffeine
content in coffee as influenced by grinding and brewing techniques. Food
Research International, 29 (8), 785-789.
- Willetts, P., Buxton, P., Chapman, S., Brereton, P. and
Wood, R. (1994). Studies of the properties and xanthine composition of the
herbal supplement guarana. Proceedings of Euro Food Tox IV,
- Ministry of Agriculture, Fisheries and Food (1997). Survey
of caffeine in energy drinks and other caffeine-containing products. Report
FD 96/39. Final Report submitted by MAFF CSL Food Science Laboratory,
Norwich, February 1997.
- Ministry of Agriculture, Fisheries and Food (1996). Food
Analysis and Performance Assessment Scheme (FAPAS) Report 0313, CSL Food
Science Laboratory, January 1996.
- Consumers Association (1995). Which?, September
- Hadorn, H. (1980) Theobromine-, caffeine- and total
alkaloid contents of cocoa mass. CCB Review for Chocolate, Confectionery
and Bakery, 5(3), 26-28.
- Timbie, D.J., Sechrist, L. and Keeney, P.G. (1978).
Application of high pressure liquid chromatography to the study of variables
affecting theobromine and caffeine concentrations in cocoa beans. Journal
of Food Science,
- The Coffee and Coffee Products (Amendment)
Regulations 1987 (S.I.  No. 1986). HMSO.
- European Community (1979). Commission Directive
79/1066/EEC laying down Community methods of analysis for testing coffee
extracts and chicory extracts. Official Journal of the European Communities
For further information please contact:
Dr A M Davies
Joint Food Safety and Standards Group
Novel Foods Division
Room 232 Ergon House
c/o Nobel House
LONDON SW1P 3JR
Tel: +44 (0) 171 238 6217
Fax: +44 (0) 171
Table A1: Concentrations
of caffeine, theobromine and theophylline in cola drinks.
Concentrations of caffeine, theobromine and theophylline in "energy"
Table A3: Concentrations of caffeine, theobromine and theophylline
in miscellaneous drinks.
Table A4: Concentrations of caffeine, theobromine
and theophylline in tea products.
Table A5: Concentrations of caffeine,
theobromine and theophylline in coffee products.
Table A6: Concentrations of
caffeine, theobromine and theophylline in chocolate products.
Table B1: Caffeine
concentrations in tea products as reported in the scientifiic literature.
B2: Caffeine concentrations in coffee products as reported in the scientifiic
Click here to download the Excel version of Annexes A
If you have any other spreadsheet package:
here to download the .csv version of Table A1
here to download the .csv version of Table A2
here to download the .csv version of Table A3
here to download the .csv version of Table A4
here to download the .csv version of Table A5
here to download the .csv version of Table A6
here to download the .csv version of Table B1
here to download the .csv version of Table B2
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