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Hangout no.5: Nutrición Deportiva - Tabla cafeína
1. AIS WEBSITE FACT SHEET – AIS SPORTS SUPPLEMENT PROGRAM
Caffeine
Supplement Overview
Caffeine (1,3,7-trimethylxanthine), is a substance found naturally in the leaves, beans and fruits
of a variety of plants, and is regularly consumed by ~ 90% of adults. The most common dietary
source of caffeine is coffee, but cola drinks, energy drinks and specialised sports foods and
supplements also contribute to regular intake. We lack accurate information on the typical daily
caffeine intakes of Australians; however, it is likely to be around 250-300 mg (3-5 mg/kg body
mass).
Caffeine intake has been linked with a number of health issues; however whether caffeine
contributes to an increased or decreased risk of various diseases is unclear. Various health
agencies from countries around the world consider caffeine to be a generally safe compound
especially when it is consumed in low to moderate levels. These levels are defined as
Low: 80-250 mg/d (1.1-3.5 mg/kg BM)
Moderate: 300-400 mg/d (4-6 mg/kg BM/d)
The use of caffeine by children carries greater risk, and children < 12 y are suggested to limit
caffeine intake to < 2.5 mg/kg/d.
On 1 January 2004, caffeine was removed from the 2004 World Anti-Doping Agency Prohibited
List, allowing athletes who compete in sports compliant with the WADA code to consume
caffeine within their usual diets or for specific purposes of performance. This change was based
on the recognition that caffeine enhances performance at doses that are indistinguishable from
everyday caffeine use, and that the previous practice of monitoring caffeine use via urinary
caffeine concentrations is not reliable. WADA continues to test urinary caffeine concentrations
within its Monitoring program to investigate patterns of misuse of substances in sport. This
Monitoring Program has not revealed systematic changes of use or abuse of caffeine in sport
since the 2004 status change.
Caffeine is rapidly absorbed and transported to all body tissues and organs where it exerts a
large variety of effects. The mechanisms underpinning these effects may vary between
individuals and include both positive and negative responses. Effects include the mobilisation of
fats from adipose tissue and the muscle cell, changes to muscle contractility, alterations to the
central nervous system to change perceptions of effort or fatigue, stimulation of the release and
activity of adrenaline, and effects on cardiac muscle.
Some popular beliefs about caffeine have been refuted by recent research:
1. Caffeine enhances endurance performance because it promotes an increase in the utilisation
of fat as an exercise fuel and 'spares' the use of the limited muscle stores of glycogen. In fact,
studies now show that the effect of caffeine on 'glycogen sparing' during sub-maximal
exercise is short-lived and inconsistent - not all athletes respond in this way. Therefore, it is
unlikely to explain the enhancement of exercise capacity and performance seen in
prolonged continuous events and exercise protocols.
2. Caffeine-containing drinks have a diuretic effect and cause an athlete to become dehydrated.
In fact, small to moderate doses of caffeine have minor effects on urine losses or the overall
hydration in people who are habitual caffeine users. In addition, caffeine-containing drinks
2. such as tea, coffee and cola drinks provide a significant source of fluid in the everyday diets
of many people.
Evidence of the use of caffeine to enhance sports performance is at least a century old and a
robust body of research on caffeine and exercise has developed over the last 40 years. New
insights which have evolved over the past decade include the following:
Caffeine intake enhances the performance of a wide variety of sports (see situations for
use in sport).
A variety of protocols of caffeine intake, including consumption before and during
exercise, can enhance performance. Furthermore, caffeine doses as low as 2-3 mg/kg
are effective. Thus, the “standard” protocol of caffeine use - a dose of 6 mg/kg body
mass (BM) taken an hour prior to exercise - needs to be updated (see products and
protocols).
The major benefits of caffeine on exercise capacity and performance appear to be
achieved by central nervous system effects. These effects reduce the perception of
fatigue and allow optimal pacing and skill/work outcomes to be maintained for a longer
period.
Individuals vary in their response to caffeine intake. Although caffeine may enhance
sports performance in most people, some people are non-responders and others may
respond negatively.
Products and protocols
A range of products provide caffeine in our everyday diets. Table 1 provides a summary of common
foods, drinks and over-the-counter preparations available in Australia, while Table 2 provides a
summary of products that are more specifically targeted to athletes. Several issues are noted:
The manufacture of caffeine containing products in Australia is regulated variously by Food
Standards Australia New Zealand (“FSANZ”) or the Therapeutic Goods Administration. Foods,
which naturally contain caffeine and have a long history of use and consumer
awareness/association with caffeine, such as tea, coffee and cocoa, are exempt from labelling
requirements and the addition of these caffeine sources to other foods is allowed.
Although values for the “typical” or “average” caffeine content of different types of coffee
beverages can be gained from food tables, there is a considerable range in the actual caffeine
content of these beverages. This is the case even when standard preparations are compared; for
example, the same preparation from commercial coffee outlets, including the same franchise or
the same outlet on different days. Therefore, it is difficult to predict or guarantee a desired dose
of caffeine using coffee as a source.
Coffee can potentially provide a substantial dose of caffeine in a single serve. Studies of
beverages purchased from commercial outlets have documented caffeine doses of >200 mg in a
small volume caffeine beverage and >500 mg in a large volume beverage from specialty coffee
franchises.
Iced coffee and cold caffeinated drinks (i.e. frappes) can also contain a substantial dose of
caffeine with a commercially available single serve providing up to 200 mg of caffeine.
Cola drinks, energy drinks, sports foods and therapeutic goods represent an additional source of
caffeine in the food supply and are a popular choice among specific population groups (e.g.
adolescents and young adults). While cola drinks have been available for over a century,
“energy” drinks are a more recent and increasingly popular caffeine source. The Australian
3. Foods Standards Code allow for the addition of caffeine to cola drinks at a maximum level of 145
mg/L while energy drinks, known in the code as Formulated Caffeinated Beverages, can contain
caffeine from all sources (caffeine and guarana) of up to 320 mg/L. Energy drinks must state
their caffeine content on product labels.
The Australian Food Standards Code provides greater regulation of caffeine-added products than
found in other countries. It restricts the development of new food products containing non-
traditional sources of caffeine (including guarana) beyond the current provisions. In May 2011,
FSANZ announced a further review of the Policy Guidelines on the addition of caffeine to foods.
*Denotes range of values from studies in which standard serves of the same beverage were analysed
# cola and energy drinks are available in a range of individual serve sizes ranging from 150 ml-750 ml.
Table 1: Caffeine content of common foods, drinks and therapeutic products (Australia)
adapted from Burke et al. 2012 from a variety of sources
Food or Drink Serve# Caffeine Content (mg)
Instant coffee 250 ml cup 60 (12-169)*
Brewed coffee 250 ml cup 80 (40-110)*
Brewed coffee (same outlet on different days) 250 ml cup 130-282*
Short black coffee/espresso from variety of outlets 1 standard serve 107 (25-214)*
Starbucks Breakfast Blend brewed coffee 600 ml (Venti size) 415 (300-564*)
Iced coffee - Commercial Brands 500 ml bottle 30-200 depending on brand
Frappuccino 375 ml cup 90
Tea 250 ml cup 27 (9-51)*
Black tea 250 ml cup 25-110
Green tea 250 ml cup 30-50
Iced Tea 600 ml bottle 20-40
Hot chocolate 250 ml cup 5-10
Chocolate – milk 60 g 5-15
Chocolate – dark 60 g 10-50
Viking chocolate bar 60 g 58
Coca Cola# 375 ml can/600 ml bottle 36/58
Diet Coke 375 ml can/600 ml bottle 48/77
Pepsi 375 ml can/600 ml bottle 40/64
Red Bull energy drink# 250 ml /330 ml/500 ml can 80/106/160
V Energy drink 250 ml/350 ml/500 ml 78/109/155
Mother energy drink 150/300 ml/500 ml can 48/96/160
Monster energy drink 340 ml/500 ml can 109/160
Lipovitan energy drink 250 ml can 50
Rockstar 500 ml can 160
Vitamin water – energy 500 ml bottle 82
No Doz (Australia) 1 tablet 100
4. Some carbohydrate-containing sports foods, such as sports drinks, gels and bars contain small
amounts of caffeine – typically, 20-80 mg per serve (see Table 2). Two other supplement
categories also typically contain a source of caffeine: Fat loss products and Pre-
workout/”activation” supplements. Table 2 provides examples of products available in Australia,
which fall under the jurisdiction of Therapeutic Goods Administration. Concerns regarding these
supplement categories include the lack of information on the caffeine dose provided by a typical
serve of these products and the potential for large caffeine doses.
Table 2: Caffeine content of common sports foods and supplements (Australia)
Adapted from Burke et al. 2012 from a variety of sources
Product Serve Caffeine content (mg)
Sports food
Powerade Fuel+ sports drink 300 ml can 96
PowerBar caffeinated sports gel 40 g sachet 25
PowerBar double caffeinated sports gel 40 g sachet 50
PowerBar caffeinated gel blasts 60 g pouch (~9 lollies) 75
Gu caffeinated sports gel 32 g sachet 20-40
Carboshotz caffeinated sports gel 50 g sachet 80
PB speed sports gels 35 g sachet 40
PowerBar Performance bar with Acticaf 65 g bar 50
Pre-workout supplements
Musashi Re-activate Hard core 15 g powder serve 120
Body Science (BSc) K-OS 13 g powder 150
Jack 3D 5 g powder ? [ingredients: “caffeine”]
No-Xplode 18 g ? [ingredients: “methyl xanthine (caffeine)”]
Assault 20 g ? [ingredients: “caffeine”]
1 MR 8 g 300
No-Shotgun 22 g ? [ingredients: “caffeine”]
Amped NOS 40 g ? [ingredients: “caffeine”]
Animal Rage 1 stick ? (ingredients note caffeine/coffee bean extract)
Code Red 10 g powder ? [ingredients: “caffeine”]
Fat loss supplements
Oxyelite pro 1 capsule 100
Body Science (BSc) Hydroxyburn Pro 40 g ? (24 mg guarana listed on label)
Body Science (BSc) Hydroxyburn Hardcore 3 capsules 210 (70 mg per capsule)
Muscle Tech Hydroxycut Hardcore pro 40 g sachet ? [ingredients: “caffeine”]
Shred Matrix 1 capsule ? [ingredients: “caffeine, guarana, yerba mate”]
Animal Cuts 10 g ? [ingredients: “caffeine”]
5. Table 3 shows examples of manufactured food/supplement products from the USA which
illustrate several differences in caffeine regulations between countries. A greater range of
caffeine-added products is available than in Australia and larger doses of caffeine are available in
smaller volumes or single serve portions of various items. (Note that some products with
greater amounts of caffeine/serve than permitted by FSANZ regulations – e.g. caffeine “shots” –
may be available for purchase in Australia. This is usually due to a breach of customs laws or an
attempt to exploit the so-called Trans Tasman Mutual Recognition Act which allows products
manufactured and sold in New Zealand to be imported to Australia).
A specific issue of current concern in the US is the manufacture of alcoholic drinks containing
usually unstated amounts of caffeine (e.g. “Four”, “Joose”). The consumption of large amounts of
caffeine in association with alcohol is of concern. These products have recently been challenged by
the US regulator (Food and Drug Administration; FDA), leading to pledges by manufacturers to
reformulate their products to remove the caffeine.
The traditional protocol of caffeine use in sport and sports science research has been:
A caffeine dose equivalent to 6 mg/kg body mass, consumed 60 min prior to the start
exercise.
Typically, a period of caffeine withdrawal prior to the competition or study trial to
heighten the effect of caffeine. Caffeine withdrawal can be achieved by 24-48 hour of
absence of caffeine consumption.
Over the last decade, however, it has become clear that this traditional protocol is not best practice
and needs to be updated:
A large number of studies now show that caffeine intake can enhance performance at
significantly lower doses of intake – i.e. 1-3 mg/kg. If there is a dose–response relationship
between caffeine intake and exercise performance (i.e. the bigger the dose, the better the
performance outcome), the plateau seems to occur at a dose of ~ 3 mg/kg. This offers athletes
the opportunity to consume caffeine for performance benefits at doses that are less likely to
Table 3: Caffeine content of other sources available in USA.
Adapted from Burke et al. 2012 from a variety of sources
Food or Drink Serve Caffeine Content (mg)
AMP Energy 500 ml can 143
Spike Shotgun energy drink 500 ml can 350
Fixx Extreme Ultra shot 5 ml shot 400
Ammo energy shot 30 g shot 170
Jolt endurance shot 60 g shot 200
Extreme Sports beans – caffeine 28 g packet 50
Jolt caffeinated gum 1 stick 40
Stay Alert gum 1 stick 100
Excedrin Extra strength 1 tablet 65
No Doz (Maximum strength) 1 tablet 200
6. cause side effects, well within normal population caffeine use patterns, and from the caffeine
doses provided by a range of well accepted foods and sports foods
Studies and anecdotal observations now show that benefits from caffeine occur soon after
intake and are not reliant on the achievement of peak blood caffeine concentrations.
These sources also show that there are a variety of protocols of caffeine intake that can enhance
performance. These include the consumption of caffeine before the exercise bout, spread
throughout exercise, or late in exercise as fatigue is beginning to occur. Different protocols may
achieve optimal performance outcomes even in the same sport or individual. Suitable or
optimal protocols may be dictated by the specific characteristics of the event, the practical
considerations of consuming a caffeine-containing product, and the individual
characteristics/preferences of the athlete. The athlete who is intending to use caffeine to
enhance sports performance should experiment in training or less important events to
determine the protocol(s) which best suit their individual needs.
There is doubt about the value of withdrawing from caffeine use prior to using it for competition
to “heighten” the subsequent effect on performance. Observations of a greater performance
improvement following a period of caffeine abstinence may be an artefact – caffeine withdrawal
may impair general well-being and performance and the apparent increase in benefits when
caffeine is reintroduce is partly explained by the reversal of these negative effects. Well-
designed studies show that there is no difference in the performance response to caffeine
between non-users and users of caffeine, and that withdrawing athletes from caffeine does not
increase the net improvement in performance achieved with caffeine supplementation
In summary, athletes do not need to consume large doses of caffeine, or to consume more
caffeine than the rest of the population, to achieve their sporting goals. Athletes who want to
use caffeine to enhance sports performance should develop supplementation protocols that
use the lowest effective caffeine dose.
Situations for Use in Sport
Most studies of caffeine and performance have been undertaken in laboratories. Studies that
investigate performance effects in elite athletes under field conditions or during real-life sports
events are scarce and need to be undertaken before specific recommendations for caffeine
supplementation protocols can be made. Nevertheless, there is sound evidence that caffeine may
enhance the performance of a range of sports:
Endurance sports (> 60 min)
Brief sustained high-intensity sports (1-60 min)
Team and intermittent sports – work rates
Team and intermittent sports – skills and concentration
The effect of caffeine on the following aspects of sports is unclear, mostly due to a lack of available
research
Skill sports involving low intensity exercise
Single efforts involving strength or power (effects appear to be small and limited to certain
muscle groups)
Chronic effect of using caffeine to enhance training performance
7. Concerns Associated with Supplement Use
The effects of caffeine vary markedly between individuals. Each athlete should make decisions
about caffeine use, both socially and for sports performance, based on experience of their own
responsiveness and reactions, including side-effects.
There is evidence that some athletes do not follow best practice for caffeine use in training, for
competition performance or in their everyday (“social”) intake of caffeine.
The current caffeine use for training sessions and competition by some athletes is ad hoc
and unsystematic. At best, these practices are ineffective but in the worst case scenario,
they may be detrimental to health and performance.
Some athletes take unnecessarily high doses of caffeine for performance enhancement and
appear to lack awareness of the potential for side-effects or negative outcomes from such
use. The culture of sports, including the “more is better” principle might contribute to poor
caffeine supplementation practices and caffeine misuse.
Some athletes and coaches lack awareness of the new insights into caffeine and sports
performance.
The effects of the acute intake of caffeine follow a U-shaped curve. Although low-moderate doses
produce positive effects and a sense of well-being, the effects of higher doses of caffeine can be
negative. At higher levels of intake, caffeine can cause increases in heart rate, impairments or
alterations of fine motor control and technique, and anxiety or over-arousal. This may have health
consequences as well as interfering with sports performance.
Caffeine can affect sleep latency and quality, even at low levels of intake. This may interfere with
the athlete’s ability to recover between training sessions, or multi-day competitions. We are aware
of poor caffeine practices, particularly involving evening sports events, which lead to a cycle of use
of pharmaceutical aids to induce sleep, followed by caffeine to restore wakefulness and alertness
next day, and further caffeine use for subsequent performances.
There may be interactions between caffeine and other supplements/nutrients used by athletes (e.g.
bicarbonate, creatine, nitrate/beetroot juice) that need to be explored in terms of performance
outcomes and potential side-effects.
Although evidence of specific health problems is equivocal, long-term intake of large amounts of
caffeine (>500 mg per day) are generally discouraged by health authorities.
Athletes should be aware of the side-effects of withdrawal such as headaches and lethargy.
Community members are rightly concerned about caffeine misuse in sport; however, the public
perceptions of caffeine use by athletes are often misinformed and underpinned by emotive rather
than factual views. Public perceptions include the belief that some sources of caffeine (e.g.
therapeutic goods such as caffeine tablets) are inherently worse than others (e.g. coffee), even
though the caffeine dose may be smaller and able to be planned. Other beliefs are that caffeine use
for sports performance contravenes the ethics of sport, or that caffeine achieves a stimulatory effect
that gives athletes a super-human advantage. In fact, the “spirit of sport” is one of the three factors
that are considered by WADA in its deliberations to remove caffeine from the Prohibited List.
Furthermore, the new research on caffeine and sports performance shows that caffeine exerts its
major effect by reducing the actual or perceived fatigue which occurs when an activity is undertaken
for a prolonged period. This is similar to the benefit that underpins the everyday use of caffeine by
community members: caffeine enhances well-being and alertness and increases the time that an
individual can sustain their optimal output or pace while undertaking occupational or recreational
activities.