Whether you’re a coffee lover, tea enthusiast, or are perhaps quite partial to both, many of us rely on a caffeine hit in the morning to help kick-start our day and give us that extra burst of energy we need to tackle the tasks ahead.
But what actually is caffeine? Without delving too deep into the science, in short caffeine is an alkaloid occurring naturally in certain seeds, nuts and leaves in around 60 plant species. It is the most widely consumed psychoactive substance in the world and is technically classed as a legal ‘drug’ because it stimulates the central nervous system, causing increased alertness.
There is no ‘safe’ level of intake as such, because like any drug, caffeine exerts different effects from person to person. This can depend on:
However, guidance from the NHS advise against consuming more than 400mg of caffeine a day for adults (the equivalent of roughly four cups of coffee) and no more than 200mg of caffeine a day for pregnant women. These guidelines are based on evidence that suggests consuming up to this amount of caffeine per day won't heighten the risk of any adverse long-term health effects. Without knowing how much caffeine naturally occurs in our favourite beverages, sticking to these guidelines can be tricky!
According to the National Diet and Nutrition Survey, coffee is by far the largest contributor of caffeine to the average UK diet, with tea coming a close second. In fact, approximately 95 million cups of coffee are drank every day in the UK and it’s estimated that we will spend more than £4bn getting our caffeine hit from high street coffee shops and cafes this year.
To be able to watch your intake, it’s important to consider that caffeine is present in lots of popular food and drinks other than coffee.
|Rockstar can (500ml)||200mg|
|Large cup of filter coffee (500ml)||180mg|
|Relentless can (500ml)||160mg|
|Monster can (500ml)||160mg|
|Cup filter coffee (200ml)||90mg|
|Redbull can (250ml)||80mg|
|1 shot espresso||80mg|
|Cup of instant coffee (200ml)||63mg|
|Cup of black tea (220ml)||50mg|
|Diet Coke can (330ml)||42mg|
|Green tea (200ml)||35mg|
|Coca-Cola can (300ml)||32mg|
|Coke Zero can (330ml)||32mg|
|Small dark chocolate bar (50g)||25mg|
|Cup of coffee shop hot chocolate (200ml)||25mg|
|Cup of decaf coffee (220ml)||3mg|
Caffeinated products play a dominant role in modern society, so it’s important to be aware of any potential health risks linked to caffeine consumption.
Worsened menopause symptoms
Caffeine and alcohol have both been shown to make hot flushes, experienced by women during the menopause, worse – especially in those people already sensitive to the effects of caffeine.
In certain groups, such as those with diagnosed anxiety disorders, some reports indicate increased levels of anxiety and impaired sleep when consuming large amounts of caffeine (more than 5 cups of coffee a day).
Short term health effects
Some individuals may experience adverse effects relating to the central nervous system including interrupted sleep, headaches, irritability, and behavioural changes. Some studies have also indicated increased incidences of aggressive behaviour among adolescents regularly consuming caffeinated products, especially popular caffeinated energy drinks.
High blood pressure
The NHS suggest that drinking 4 or more cups of coffee a day (equivalent to approx. 400mg caffeine) may increase blood pressure, so recommends sticking to within the UK guidelines. Conversely, some studies indicate that coffee contains beneficial compounds such as antioxidants which may have a protective effect on blood vessels. So, as always – eat a healthy balanced diet as everything is fine in moderation.
Those choosing to cut down on caffeine may experience withdrawal symptoms such as headaches, low mood, fatigue and tremors if they stop suddenly, therefore it’s advised to reduce caffeine intake gradually over time.
Caffeine gets a lot of bad press, but when drank in moderation, the effects often appear more positive than negative.
Drinking a cup of coffee 30 minutes before exercise can allow you to exercise for up to 30% longer. This is thought to be down to stimulation of the central nervous system, making exercise feel like less of an effort and reduces pain. Also, during high intensity activities caffeine may increase the number of fibres used in muscle contraction, meaning movements may be more forceful.
As already mentioned, caffeine has been shown to both increase alertness and reduce fatigue, which is especially beneficial in low arousal situations, such as working late at night. It also may improve the performance of intricate tasks that require close attention, as well as simpler tasks that require greater patience to complete.
Low to moderate caffeine intake (2-5 cups a day) has been associated with increased ability to feel pleasure and reduced anxiety. The anticipation of drinking coffee, as well the actual drinking process, is thought to be a mood booster for many, due largely to its ‘comforting’ feeling.
Some studies have suggested that increased caffeine consumption, particularly in the form of coffee, is consistently associated with lower risk of depression. The reason why coffee may have a greater protective effect against depression compared to other caffeinated beverages is thought to be due to other components in coffee, including chlorogenic acid, ferulic acid, and caffeic acid, which may work to reduce nerve cell inflammation.
Further research is required in this field, however initial research has speculated that caffeine may help to heighten metabolic rate and therefore help burn more energy during both activity and rest. There are also interesting associations being made between coffee intake and appetite regulation, with potential implications for weight management treatment.
Nutritionist Sophie Edgington (ANutr), BSc Nutrition is passionate about practising evidence-based nutrition and debunking the multitude of inaccurate myths that so readily surround food and health information. Her goal is to ensure we are all able to make informed and responsible decisions regarding our health.