Caffeine was first isolated from coffee beans in 1820. The name was derived from the plant Coffea arabica. Caffeine is also an ingredient of fruits or leaves such as the tea bush(Camellia sinensis), mate tree(Ilex paraguariensi) and cocoa tree(Theobroma cacao) as well as other plants.

Caffeine stimulates the central nervous system and the cardiovascular system in humans. In moderate doses, it increases alertness and reduces the feeling of tiredness. Depending on the individual sensitivity to caffeine and the extent of consumption of caffeine-containing foods, undesirable effects such as nervousness or cardiac arrhythmia may occur.

Relatively high levels of caffeine are found in coffee beans, in the leaves of dried, white, green and black tea, cola nuts and guarana berries. The caffeine content in cocoa beans is lower.

Caffeine is used in various foods such as caffeinated drinks, e.g. cola or energy drinks, baked goods and sweets. Bitter-tasting caffeine, provided it is used in small quantities in food, is also used as a flavouring agent.

Energy drinks ("energy drinks" or "energy shots") often have a high caffeine content.

Caffeine is also used in food supplements and medicines (especially painkillers).

Source: EFSA, 2015b; Caffeine, 2023: https://koffein.com/tabelle.html; Styrian Chamber of Labour, 2019: These are average caffeine values from 11 samples of iced tea.

In 2015, the European Food Safety Authority (EFSA) derived the following safe intake levels of caffeine that are safe for the healthy general population:

• Single doses of up to 200 mg of caffeine from all sources are safe for healthy adults. That is around 3 mg per kilogramme of body weight.
• In some adults, single doses of 100 mg of caffeine shortly before bedtime can have an effect on sleep duration and patterns.
• An intake of 400 mg per day, spread over the entire day, is safe for healthy adults - with the exception of pregnant women.
• For pregnant and breastfeeding women, a caffeine intake of 200 mg throughout the day is considered safe for the foetus. Excessive caffeine consumption over a longer period of time is associated with reduced foetal growth.
• For children and adolescents, an intake of 3 mg/kg body weight per day is considered safe.

As the consumption of energy drinks is popular among children and adolescents, the intake of caffeine can be high. When consuming one litre or more of energy drinks and subsequently exceeding the amount of caffeine intake considered safe, adverse effects such as palpitations, shortness of breath, uncontrolled muscle tremors, severe nausea, anxiety, nervousness and changes in the electrocardiogram have been observed in young adults (BfR, 2019).

Cola drinks are also popular soft drinks among children and adolescents. If these are not caffeine-free, the caffeine intake may well be higher and should therefore not be underestimated.

According to Article 10 of Regulation (EU) No. 1169/2011, foods to which more than 150 mg/l caffeine has been added as an ingredient for physiological purposes, such as for the wakefulness effect, must be labelled with the following statement: "Increased caffeine content. Not recommended for children and pregnant women". These labelling requirements also apply to food supplements with added caffeine.

According to the Austrian Food Code, energy drinks are defined as non-alcoholic soft drinks to which at least 150 mg/l of caffeine (as caffeine and/or from caffeine-containing ingredients) has been added. They also contain one or more ingredients such as inositol, glucuronolactone or taurine.

In the Austrian Food Codex, tea drinks (including iced tea) are produced from tea extracts and water in accordance with Codex Chapter B31 and contain at least 0.12% dry tea extract. If tea extracts are made from the "tea plant" Camellia sinensis L., the resulting product contains a caffeine content of at least 40 mg per 1 litre of finished beverage.

The use of caffeine as a flavouring (FL 16.016) is only permitted in certain food categories with applicable maximum levels(Regulation 1334/2008; Regulation (EU) 2018/1482) - such as "dairy products and analogues" (maximum 70 mg/kg), "ice cream" (maximum 70 mg/kg), "confectionery" (maximum 100 mg/kg) and "non-alcoholic beverages" (maximum 150 mg/kg).

This can be recognised in the list of ingredients by the designation "flavouring caffeine" and the amount of caffeine is less than 150 mg/l.

According to the Health Claims Regulation (EC) No. 1924/2006 as amended, foods containing caffeine may be advertised as increasing the ability to concentrate and physical performance.

We are analysing caffeine in various foods. The results can be viewed in the following focus section:

After oral intake, caffeine is quickly and completely absorbed and passes unhindered through the blood-brain, placenta and blood-testis barrier. In the liver, 70 - 80 % of caffeine is metabolised to paraxanthine, further broken down and excreted in the urine via the kidneys. The plasma half-life in adults is 2 to 8 hours. In pregnant women this can be up to 18 hours. This is due to the hormones oestrogen and progestogen, as these inhibit the enzyme activity for metabolisation (BfR, 2019).

Caffeine is an adenosine blocker as it binds to the same receptors as adenosine. Adenosine has a sleep-promoting effect by inhibiting the release of dopamine and glutamate. Caffeine, however, has a wakefulness-promoting effect, as the binding of caffeine to the adenosine receptor promotes the release of dopamine and glutamate, allowing them to develop their activating effect. The habituation effect of caffeine is likely to be related to the increased formation of adenosine receptors, to which more adenosine molecules can dock, or more caffeine is needed to stop the feeling of tiredness (BfR, 2019).

Dietary supplements

Food supplements can contain caffeine, from natural sources or artificially produced. According to the Health Claims Regulation (EC) No. 1924/2006 as amended , it is permitted to advertise these products for weight reduction or performance enhancement. When taking food supplements containing caffeine, it is important to consider other sources of caffeine. It is possible that the recommended daily intake of caffeine may be exceeded. The manufacturer must therefore ensure that a single serving does not exceed 200 mg. Furthermore, the maximum daily dose of 400 mg caffeine spread over the day should be adhered to. A warning on the label with "Not suitable for pregnant women, nursing mothers and children. Keep out of the reach of children." is mandatory.

Caffeine as an active pharmaceutical ingredient

Caffeine is often added to painkillers to improve their effect. This must be taken into account in the recommended daily caffeine intake.