Health
Scientific Committees
Scientific Committee on Food
Outcome of discussions
Opinion on
Caffeine, Taurine and D-Glucurono
-
g
-Lactone
as constituents of so-called "energy" drinks (expressed on
21 January 1999)
Terms of reference
To evaluate the safety of caffeine,
taurine and D-glucurono-
g
-lactone as constituents of so-called
"energy" drinks.
Background
The Committee has been asked to evaluate
the safety of caffeine, taurine and D-glucurono-
g
-lactone (glucuronolactone) in the context
of their inclusion as constituents of so-called "energy"
drinks. The term "energy" drinks has been used in this
opinion for convenience, to encompass a category of beverages
that have appeared on the European market in recent years,
which contain various combinations of substances, such as
carbohydrates, vitamins and minerals, and many of which
include one, or more of the three substances the Committee
has been asked to evaluate. It should be noted however that
the term "energy" drink is a commercial designation. It is
neither an agreed legal term for a category of foods in the
EU, nor does the Committee offer any view in this opinion as
to whether claims that these drinks provide energy, in the
conventional nutritional sense, are scientifically
justified.
The Committee is aware that the term
"energy drinks" is also used in a different way to mean
beverages containing enhanced levels of carbohydrates which
provide energy in the conventional nutritional sense, and
which are often used by sportspersons and by people
suffering from or recovering from illness. These types of
beverages will not be further discussed.
Certain Member States have requested
that the European Commission seek the opinion of the
Scientific Committee on Food (SCF) about potential health
effects from excessive consumption of "energy" drinks in
certain sectors of the population. In these requests,
neither the meaning of "excessive" nor the population
groups of concern were defined. To the Committees
knowledge, no surveillance information is available on the
maximum intakes of "energy" drinks by individual consumers.
It was agreed that initially the constituents caffeine,
taurine and glucuronolactone should be evaluated for
safety, taking into account the maximum concentrations
currently known to be present in "energy" drinks available
on the European market.
A collection of information on "energy"
drinks and their constituents was submitted by Member
States and by one company manufacturing "energy" drinks.
The information comprised advertising material, lists of
ingredients/constituents and their concentrations in
various products, per capita estimates of intake in
Austria, published opinions on "energy" drinks from
independent scientists, and reviews of the safety of
caffeine, taurine and glucuronolactone by scientists acting
on behalf of one manufacturer.
1-3 The Committee itself therefore conducted an
independent search of the published literature relating to
taurine and glucuronolactone and updated its earlier
opinion on caffeine
4 as a background to this opinion. This opinion
covers only safety considerations of these three
constituents.
Intake assumptions for "energy" drinks
Intake data for "energy" drinks are not
available, with the exception of per capita estimates for
Austria,
2 which has a well-established market for these
types of drink. A per capita estimate of 1.85 litres/year
which included non-consumers as well as consumers, was
adjusted to take account of the fact that only 9% of the
Austrian population are regular consumers of "energy"
drinks. Assuming that 80% of "energy" drinks are consumed
by regular consumers, it was estimated that the regular
consumer drinks 16.4 litres/year or approximately 50ml/day
averaged over one year. However, the Committee considered
that it was more appropriate for safety evaluation of
"energy" drinks to consider likely consumption on any one
day by regular consumers, rather than average consumption
over one year. It would be reasonable to assume that a
regular consumer of "energy" drinks might drink one to two
250 ml or 330 ml cans per day, and so in the estimates
which follow in this opinion, a consumption figure of 0.5
litre of "energy" drink per day has been assumed as a
reasonable estimate of possible intake on any one day by
regular consumers. The Committee is of course aware that,
on occasions, some individuals might drink amounts higher
than this, for example, known high consumption of
carbonated drinks in Europe is in excess of 1 litre/day and
the intake of fluid that would be required to replace body
fluids lost through sweating during, say, 2 hours of heavy
exercise would be around 1 litre. The Committee considered
that in the absence of comprehensive intake surveys, it was
impossible to anticipate the maximum intakes of "energy"
drinks which might be consumed in one day by extreme
consumers, nor was it possible to anticipate the maximum
that might consumed within a short period during the day by
some consumers. The Committee has not therefore considered
in detail the possible consequences of peak intakes in
excess of 0.5 litre per day.
CAFFEINE
Previous SCF evaluation
The possible harm to health from the
consumption of caffeine from food and beverages was
considered by the SCF in 1983.
4 It concluded at that time that there was no
apparent reason for concern about carcinogenic or mutagenic
effects of caffeine in man at normal levels of intake. The
data then reviewed did not reveal any teratogenic effects
in humans, nor any adverse effects on human reproductive
function, nor did they support any association between
caffeine consumption and adverse pregnancy outcome. Neither
did the animal studies point to clear permanent or adverse
neurobehavioural effects in rodents even at severely toxic
doses. There was little information on the effects of
exposure to caffeine on the behaviour of children.
Levels in "energy" drinks and other foods and
estimated intakes
A submission from the Austrian national
food authority
1 included a list of the caffeine contents of 32
"energy" drinks, taken from a review of beverages on the
Austrian market in March 1996. The stated caffeine content
of most "energy" drinks ranged from 240-320 mg/l.
Consumption of caffeine from "energy" drinks by regular
consumers in Austria, which has a well-established market
and where consumption is thought to be highest, has been
estimated by one of the manufacturers of "energy" drinks to
be about 14.4 mg/day on average,
3 equivalent to 0.24 mg/kg bw/day for a 60 kg
person. However, using the Committees assumption for
regular consumers of consumption of 0.5 l of "energy"
drinks per day, containing the maximum level of 320 mg/l,
caffeine intake would amount to 160 mg caffeine/day or 2.7
mg/kg bw/day for a 60 kg adult or 5.3 mg/kg bw/day for a 30
kg child.
A recent comprehensive survey in the UK
of the caffeine content of "energy" drinks and other
caffeine-containing products, such as cola drinks, tea,
coffee and chocolate products, has revealed a wide range of
caffeine concentrations in the respective product ranges.
6 Tea, coffee and chocolate drinks were made up
using standardised procedures. The caffeine contents of 32
cola drinks ranged from 33-213 mg/l. Twenty-six "energy"
drinks had a broad range of caffeine contents from 0.5-349
mg/l, but most contained over 110 mg/l, with a mean of 240
mg/l and a median of 293 mg/l. Tea infusions made from 14
samples of tea bags had caffeine contents ranging from
245-430 mg/l, while infusions made from 3 samples of loose
leaf tea ranged from 95-105 mg/l. Caffeine levels in 16
standard instant coffees were 210-340 mg/l, while 8 filter
and percolated coffees were 105-215 mg/l. Levels in 18
chocolate drinks ranged from 5.5-41 mg/l and levels in 6
chocolate bars ranged from 110-710 mg/kg. The UK survey did
not offer any estimates of caffeine intakes but pointed out
the need for data on the consumption of these
products.
In its 1983 report on caffeine,
4 the Committee stated that for an average EEC
consumer, the intake from cola-type beverages ranged from
0.013 mg/kg bw/day to 0.48 mg/kg bw/day, while caffeine
exposure from all sources, including coffee, tea,
chocolate, etc, ranged from 2.4 mg/kg bw/day to 4.5 mg/kg
bw/day, averaging 3.5 mg/kg bw/day. Pregnant women were
estimated to have lower average exposures of 2.0 mg/kg
bw/day. More recent estimates of consumption of caffeine by
consumers are available for some European countries. In
Germany, a median value of 7.8 mg/kg bw/day was estimated
for adult coffee drinkers.
3 In Denmark the estimate for all consumers was
a mean of 7mg/kg bw/day, and for heavy consumers (90
th percentile) 14.9mg/kg bw.
5 In the UK, the mean intake for all consumers
was 4 mg/kg bw/day, and 7.5 mg/kg bw/day for heavy
consumers (90
th percentile).
5 Estimates of mean intakes in pregnant women
were slightly lower than for all consumers at 5.8 mg/kg
bw/day and 3.4 mg/kg bw/day in Denmark and the UK
respectively.
5
Biological and toxicological information
The biological and toxicological
behaviour of caffeine has been studied in numerous animal
and human investigations. The evaluation which follows
updates those aspects of the Committee's earlier opinion
4 which are considered to be most relevant to
the consumption of caffeine in "energy" drinks, focusing on
pregnant women and children.
Caffeine exposure during pregnancy in
rodents is associated with intrauterine growth retardation,
increases in resorptions and malformations, particularly
facial clefts and ectrodactyly.
7 A recent 2-generation study in rats showed
reduced pup weights.
8 Low dose exposure during pregnancy in rats
caused only inconsistent post-weaning behavioural effects
in the offspring. Higher doses were associated with lower
birth weights and delayed physical development.
9-11 One study in primates has shown caffeine
exposure to be associated with increased still births,
miscarriages, reduced birth weight and impaired postnatal
performance in a behavioural task.
12 Some studies suggest caffeine is a
competitive inhibitor of benzodiazepine receptors at very
high doses and at low doses to have a selective affinity
for adenosine receptors, thus acting as an inhibitory
neuro-modulator.
11 In general, the animal evidence indicates
that doses around 10-20 mg/kg bw/day may be minimal effect
levels for some effects such as behavioural changes and
reduced birth weight, while higher bolus doses of 50-80
mg/kg bw/day or more are required to elicit teratogenic
effects.
7
Contradictory results have been noted in
human studies on the effects of prenatal caffeine intake on
birth weight.
13-19 Some reviews attribute apparent effects of
caffeine on birth weight to the confounding effect of
smoking. No clear association has been established between
caffeine intake in early pregnancy and spontaneous abortion
14,19-23 or delayed conception.
14,24-29 Similarly there are no consistent
associations between prenatal caffeine exposure and
pre-term delivery
13,14,30,31 or congenital malformation.
13,14 A single, recent epidemiological study
showed an association between heavy caffeine intake in
pregnancy and sudden infant death syndrome.
32 In many of the human studies reviewed,
caffeine consumers have been sub-divided into low, moderate
and high consumers for analysis of data. In those studies
indicating effects on pregnancy outcome, the association
with caffeine was often confined to high consumers. In
general, maternal caffeine consumption during pregnancy
does not appear to have any measurable adverse consequences
for the human foetus at intakes up to 300 mg/day.
Studies on prenatal caffeine exposure
have shown no consistent behavioural or cognitive effects
on children either at pre-school or school age. A long-term
follow-up study in children whose mothers were exposed to
150-200 mg caffeine/day during pregnancy found no clear
effects on mental development, psychomotor functions or
behaviour up to 7 years of age.
33,34
Caffeine appears in breast milk but has
not been detected in the urine of breast-fed infants even
when maternal caffeine consumption was high.
35 Studies on the effects of direct caffeine
consumption by pre-school and school children have given
variable results. In experimental studies in which single
doses up to 10 mg/kg bw have been given to children, either
no effect or small, inconsistent effects have been noted on
mood, behavioural, cognitive and motor functions, some of
which could be interpreted as beneficial.
35-42 Some of these studies indicated that a
dose of 5 mg/kg bw increased arousal, irritability,
nervousness or anxiety in some subjects, particularly if
they were normally low consumers of caffeine.
In addition to reproductive and
behavioural effects, the Committee has also considered
whether there might be an increased risk of cardiovascular
effects from caffeine alone or caffeine in combination with
other constituents, such as taurine, present in some types
of "energy" drinks, particularly if consumed rapidly during
or after intense exercise . The evidence from human
studies, which have included normal individuals at rest,
those undergoing intense exercise and those predisposed to
cardiac arrythmias, have not indicated risks from normal
intakes of caffeine alone. The possible effects from a
combination of taurine and caffeine have not been
studied.
Conclusions
A possible intake of 160 mg caffeine/day
from 0.5l of "energy" drinks containing the maximum level
of 320 mg caffeine/l could represent a significant
contribution to total daily caffeine intake. However, this
should be compared with possible intakes from other
caffeine-containing beverages such as tea or coffee, many
of which have caffeine contents in the range 100-400 mg/l.
Such a comparison suggests that overall daily intake of
caffeine is likely to be comparable, whether soft drinks
including "energy" drinks, or tea and coffee, or a mixture
of these, are selected, assuming that "energy" drinks
replace other sources of caffeine. In the light of this,
the contribution of "energy" drinks to overall caffeine
intake does not appear to be a matter of concern for
non-pregnant adults.
For children who do not normally consume
much tea or coffee, and who might substitute "energy"
drinks for cola or other soft drinks, consumption
of"energy" drinks might represent an increase in daily
caffeine exposure compared with their previous intake. For
example, consumption of 160 mg caffeine/day from 0.5l of
"energy" drink would be equivalent to 5.3 mg/kg bw/day for
a 10 year-old, 30 kg child. This could result in transient
behavioural changes, such as increased arousal,
irritability, nervousness or anxiety.
Risk assessment in relation to pregnancy
is more difficult. Most of the available epidemiological
data suggest there is no problem if total intake is below
300 mg caffeine/day. The question of possible effects on
pregnancy and the offspring at regular intakes above this
level remains open. This suggests that moderation of
caffeine intake, from whatever source, is advisable during
pregnancy.
TAURINE
Levels in "energy" drinks and other foods and
estimated intakes
Taurine occurs naturally in food,
especially in seafood and meat. The mean daily intake from
omnivore diets was determined to be around 58 mg (range
from 9 to 372 mg) and to be low or negligible from a strict
vegan diet.
43 In another study taurine intake was estimated
to be generally less than 200 mg/day, even in individuals
eating a high meat diet.
44 According to another study, taurine
consumption was estimated to vary between 40 to 400 mg/day.
45
A submission from the Austrian National
Food Authority
1 included a list of the contents of 32 "energy"
drinks taken from a published review of drinks on the
Austrian market in 1996. Some "energy" drinks did not
contain any taurine. In those drinks in which taurine was
present and its concentration declared, one contained 300
mg/l, one 2000 mg/l, and 11 contained 4000 mg/l. From the
per capita intake of "energy" drinks averaged over a year
for regular consumers in Austria (see earlier),
2 intakes of taurine can be estimated to average
200 mg/day from "energy" drinks containing 4000 mg/l. Using
the Committees estimate of regular consumption of 0.5
l/day of "energy" drinks containing the highest level of
taurine, daily intake of taurine would be 2000 mg/day. This
is 5 times greater than the highest estimated intake of 400
mg/day from naturally occurring taurine in omnivore diets
and at least an order of magnitude above average dietary
intakes.
Biological and toxicological information
Taurine is present in the diet and is a
normal metabolite in humans. It is a metabolic product of
sulphur amino acids, mainly biosynthesised from cysteine in
the liver. It participates in the formation of bile salts
and the detoxification of certain xenobiotics. It is
involved in a number of crucial physiological processes
including modulation of calcium flux and neuronal
excitability, osmoregulation, and membrane stabilisation.
46,47 However, the role of taurine in these
processes is not clearly understood and the influence of
high taurine doses on these processes is uncertain.
Human clinical studies show that the
oral intake of taurine can influence physiological
functions. For example, taurine (3 or 6 g/day) decreased
blood pressure in hypertension patients.
47,48 A similar effect was seen in animal models
of hypertension but the mechanism of action is unknown. A
substantial increase in the plasma concentration of growth
hormone was reported in some epileptic patients during
taurine tolerance testing (oral dose of 50 mg/kg bw/day),
suggesting a potential to stimulate the hypothalamus and to
modify neuroendocrine function, similar to that seen with
certain other amino acids, such as arginine and histidine.
49 The effect on growth hormone is probably
attributable to its known hypoglycaemic action. There is an
indication that taurine (2 g/day) has some function in the
maintenance and possibly in the induction of the psoriatic
state.
50
The effects of an "energy" drink on
heart rate, plasma catecholamines, endurance time and other
parameters were investigated in male, exercising
endurance-athletes.
51 The subjects consumed an original "energy"
drink containing taurine, glucuronolactone and caffeine
and, at different times, control drinks, one without
taurine and glucuronolactone and one without all three
ingredients. The authors concluded that the study showed a
positive effect of taurine-containing drinks on hormonal
responses which led to a higher performance. However, the
design of the study does not allow a distinction to be made
between effects caused by taurine, or by glucuronolactone,
or by both substances.
Toxicological studies did not reveal any
indication for a genotoxic, carcinogenic or teratogenic
potential of taurine.
52-64 However, there is no adequate study on
chronic toxicity/carcinogenicity. Investigation of
subacute/subchronic toxicity has also been fragmentary.
65-71 Overall, the available data are
insufficient to establish an upper safe level for daily
intake of taurine.
In a 6-week preliminary study in rats, a
decrease in body weight was observed at 2000 ppm taurine in
the diet. From this experiment, the dose causing a 10%
reduction in body weight was estimated to be 1500 ppm,
corresponding to 120 mg/kg bw/day.
54 The margin between this effect level and
possible daily intakes in regular adult consumers of
"energy" drinks (around 30 mg/kg b.w.) is small. Rats given
taurine intravenously for 13 weeks showed an increase in
water consumption at 1000 and 2000 mg/kg bw/day and
haemosiderin deposition in the lungs at 2000 mg/kg bw/day.
69 The authors conclude, that the maximum
no-effect dose was 500 mg/kg bw/day, while a group of
reviewers has argued that 1000 mg/kg bw/day, is the more
appropriate no-observed-adverse-effect level, because the
minor nature of the effect and the likely relation to the
osmotic activity of the test substance.
2 Administration of 0.4% taurine in drinking
water to guinea pigs for 2 weeks, corresponding to 462
mg/kg bw/day, led to fatty infiltration of the liver.
64 In a 2-week study with rats receiving 1%
taurine in drinking water (about 2.6 g/kg bw/day) changes
in neutral lipids, phospholipids and enzyme activities
related to lipid metabolism in liver microsomal membranes
were observed.
66 In neither study was a no-effect level
established. In other studies of longer duration,
parameters corresponding to those described above were not
examined.
Numerous publications describe special
effects of taurine in different animal models, e.g. on
behavior, blood pressure, serum glucose and serum
cholesterol. Taurine was mostly applied in doses of 1000
mg/kg bw/day and above to induce these effects, using the
oral route of administration. Intraperitoneal injection of
taurine, however, seems to influence behavioral parameters
at much lower doses. In one study, even a dose of 1.5 mg/kg
bw was reported to decrease psychomotor activity.
72
Animal experiments show that taurine
protects against many adverse effects induced by
xenobiotics. On the other hand, taurine also has the
capacity to enhance chemically induced toxicity, e.g.
taurine not only suppresses but also enhances lipid
peroxide formation in the liver induced by carbon
tetrachloride depending on the experimental conditions.
73,74 It should be noted that the combination of
taurine with caffeine has not been studied with respect to
any interactions.
Conclusions
The intake of taurine from regular
consumption of some taurine-containing "energy" drinks is
several times higher than that from the rest of the diet.
There is only limited information available either from
human or conventional animal studies for risk assessment of
taurine. There is a lack of scientific evidence to support
the safety of taurine present in beverages at
concentrations that may result in intakes several-fold
higher than that usually obtained from the rest of the
diet. Given the available information on involvement of
taurine in a number of key physiological processes,
together with the very limited data on possible adverse
effects of taurine in humans and laboratory animals and the
doses at which such effects were reported, the Committee
considers it likely that the margin between normal daily
intake of taurine from the diet (excluding consumption of
"energy" drinks) and an adverse effect level in humans may
be relatively small. At present, there is insufficient
information on which to set an upper safe level for daily
intake of taurine.
It may also be necessary to take into
consideration, that absorption of taurine from beverages
may be more rapid than from a food matrix. As, mentioned
earlier, potential interactions between taurine and
caffeine, both of which are present in several "energy"
drinks, have not been sufficiently investigated.
Against this background, the Committee
is unable to conclude that the safety-in-use of taurine in
the concentration range reported for taurine in "energy"
drinks has been adequately established. Further studies
would be required to establish an upper safe level for
daily intake of taurine.
D-GLUCURONO-
g
-LACTONE
Levels in "energy" drinks and other foods and
estimated intakes
A submission from the Austrian national
food authority
1 included a list of the contents of 32 "energy
drinks", taken from a published review of drinks on the
Austrian market in March 1996. Not all "energy" drinks
contain glucuronolactone. The stated concentrations in
those drinks containing glucuronolactone ranged from
2000-2400 mg/l. From the per capita intake of "energy"
drinks averaged over a year for regular consumers in
Austria (see earlier),
2 intakes of glucuronolactone can be estimated
to average 108 mg/day from "energy" drinks containing 2400
mg/l. This is equivalent to 1.8 and 3.6 mg/kg bw/day for
mean and 90
th percentile intakes of 60 kg persons.
2 Using the Committees assumption of regular
consumption of 0.5l/day, containing a maximum level of
glucuronolactone of 2400 mg/l, would give an intake of 1200
mg/day, or 20 mg/kg bw/day for a 60 kg adult or 40 mg/kg
bw/day for a 10 year-old, 30 kg child.
These estimates of intake from "energy"
drinks can be compared with estimates of intake of
glucuronolactone from other food sources. However, only a
small number of foods have been identified as containing
glucuronolactone and such comparisons should therefore be
treated with caution. In the USA, mean and 90
th percentile intakes from other food sources
have been estimated at 1.2 and 2.3 mg/day respectively
among those consuming glucuronolactone containing foods, of
which wine is the richest source (up to 20mg/l).
75 Based on this USA estimate, daily intake of
glucuronolactone by regular consumers of two 250ml cans of
energy drinks containing 2400 mg/l could exceed intake from
other food sources by up to 500-fold.
Biological and toxicological information
D-Glucurono-
g
-lactone is a normal human metabolite
formed from glucose. At physiological pH, it is in
equilibrium with glucuronic acid, its immediate precursor.
Glucuronic acid occurs in plants, mainly in gums, but is in
polymeric combination with other carbohydrates so is not
readily bioavailable. Glucuronic acid is also an important
constituent of fibrous and connective tissues in all animals.
The available data
75 indicate that when glucuronolactone is
administered orally to humans it is rapidly absorbed,
metabolised and excreted as glucaric acid, xylitol and
L-xylulose. Animals, such as rodents, which can synthesise
vitamin C endogenously do so from glucuronic acid, either via
its conversion to gulonic acid or to glucuronolactone, and
hence to gulonolactone, then ascorbic acid. Such animals can
also convert exogenously administered glucuronolactone into
vitamin C. However, primates, including man, and guinea pigs
do not possess this metabolic pathway. For this reason, the
rodent may be an inappropriate model for man in the study of
the effects of glucuronolactone.
The available toxicity studies are
extremely limited. Acute toxicity studies have been carried
out in rat, mouse, dog, rabbit and cat by oral,
intravenous, intraperitoneal and subcutaneous routes.
76 It is of low acute toxicity, with the oral
route being the least toxic; LD50 values ranged from 940
mg/kg bodyweight following intravenous administration in
dog and rabbit, up to 10,700 mg/kg bodyweight and
>20,000 mg/kg bodyweight following oral administration
in rat and mouse respectively.
Glucuronolactone was administered to rats
in a study designed to test the hypothesis that, as an
inhibitor of
b
-glucuronidase, it would increase
longevity by increasing the rate of excretion of toxic
substances as glucuronides.
77 The hypothesis was based on the assumption that
intestinal
b
-glucuronidase decreases the rate of
excretion of toxic substances by allowing enterohepatic
recirculation of aglycones split from glucuronides.
Administration of glucuronolactone in the drinking water at
127 mg/day, equivalent to around 295-330 mg/kg bodyweight to
rats from one year of age for the rest of their lifetime had
no effect on fluid intake, bodyweight, time of death, or
cause of death as determined by autopsy.
A study on glucuronolactone was carried
out in dogs to follow up on observations that xylitol is a
strong stimulator of insulin secretion in that species.
78 It was assumed that glucuronolactone would be
converted to xylitol since, in the body, it is
interconvertible with D-glucuronate which in turn is a
precursor of xylitol in the glucuronate-xylulose cycle. A
single intravenous injection of glucuronolactone at 400
mg/kg bodyweight caused only a slight increase in plasma
insulin and glucose concentrations, which was small
compared with the increase in plasma insulin elicited by
xylitol or glucose itself. The authors concluded that
glucuronolactone was either not converted to xylitol in
dogs to any appreciable extent, or was metabolised in
tissues other than the pancreatic islets, or was diverted
to another metabolic pathway, such as formation of ascorbic
acid. D-glucuronate is not a good stimulator of insulin
release in rat pancreatic islets either.
79
In a study of the antimutagenic activity
of lactones in
Escherichia coli, glucuronolactone was reported to
be not mutagenic to
E.coli strains WP2 and WP2s. Unlike some other
lactones, it had no antimutagenic activity against two
other established mutagens (4NQO and MNNG).
80
A study on male endurance-athletes of
the effects of an "energy" drink containing
glucuronolactone, taurine and caffeine, which does not
allow the effects of the three components to be evaluated
separately, has already been mentioned earlier in the
discussion on taurine.
51
Glucuronolactone has also been used in
long-term therapy of chronic carriers of the typhoid organism
because of its ability to inhibit viral and bacterial
b
-glucuronidase. It was stated that
administration of between one and a few grams per day did not
give rise to problems.
81
Conclusions
Human metabolic considerations indicate
the body is likely to handle small quantities of
glucuronolactone without any problems. However, the intake
of glucuronolactone from consumption of some "energy"
drinks is possibly as much as two orders of magnitude
greater than that from the rest of the diet. There is very
little information available for risk assessment of
glucuronolactone at such intakes. While there is no
indication from the available data that there is any risk
to health from consumption of high amounts of
glucuronolactone, there is a lack of scientific evidence to
support the safety of glucuronolactone present in beverages
at concentrations that may result in intakes as much as two
orders of magnitude greater than that obtained from the
rest of the diet. As was the case with taurine, there is
insufficient information on which to set an upper safe
level for daily intake of glucuronolactone.
The Committee notes that the only study
using chronic administration has been carried out in the
rat and that rodents are known to metabolise
glucuronolactone differently from man. Rodents may thus not
be an appropriate model. There are no studies in mammalian
species that include administration of high doses of
glucuronolactone to growing animals. Knowledge of the
influence, if any, of high doses of glucuronolactone on
blood glucose homeostasis and metabolic pathways involving
glucose would also be relevant for risk assessment in
relation to children and diabetics.
Against this background, the Committee
is unable to conclude that the safety-in-use of
glucuronolactone in the concentration range reported for
glucuronolactone in "energy" drinks has been adequately
established. Further studies would be required to establish
an upper safe level for daily intake of
glucuronolactone.
Overall conclusions
"Energy" drinks are not traditional food
products and contain some constituents, such as taurine and
glucuronolactone, which, while not unique to these
products, are present in much higher concentrations in
"energy" drinks than are found in other food products
and/or natural foods.
This opinion covers only the safety
considerations for three constituents present in some
"energy" drinks, caffeine, taurine and glucuronolactone. In
the absence of comprehensive information about consumption
patterns in Member States, and in particular a lack of
information about maximum intakes among regular consumers,
the Committee has based its considerations on an assumption
that regular consumers of "energy" drinks might reasonably
consume 0.5l/day and that some of these consumers may
regularly select products containing the highest amounts of
caffeine, taurine or glucuronolactone reported to be
present in drinks on the market.
For caffeine, comparison of
concentrations in "energy" drinks with concentrations
present in other caffeine containing beverages such as tea
and coffee suggest that overall daily intake of caffeine is
likely to be comparable, whether soft drinks including
"energy" drinks, or tea and coffee, or a mixture of these,
are selected, based on the assumption that "energy" drinks
replace other sources of caffeine. Under these
circumstances, the Committee considers that the
contribution of "energy" drinks to overall caffeine intake
is not a matter of concern for non-pregnant adults.
For children who do not normally consume
much tea or coffee, and who might substitute "energy"
drinks for cola or other soft drinks, consumption
of"energy" drinks might represent an increase in daily
caffeine exposure compared with their previous intake. The
Committee considers that this could result in transient
behavioural changes, such as increased arousal,
irritability, nervousness or anxiety.
Risk assessment of caffeine in relation
to pregnancy is more difficult. While intakes up to
300mg/day appear to be safe, the question of possible
effects on pregnancy and the offspring at regular intakes
above 300mg/day remains open. This suggests that moderation
of caffeine intake, from whatever source, is advisable
during pregnancy.
The Committee notes that the possible
interactions of constituents of "energy" drinks have not
been well studied and considers that the possible
interactions between caffeine, taurine and alcohol may
warrant investigation in humans, particularly under
conditions of exercise and consequent dehydration through
sweating .
For taurine and glucuronolactone, the
Committee is unable to conclude that the safety-in-use of
taurine and glucuronolactone in the concentration ranges
reported for these constituents in "energy" drinks has been
adequately established. Further studies would be required
to establish upper safe levels for daily intake of taurine
and glucuronolactone.
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