Caffeine

Caffeine is deeply embedded in most of our lives. Here in Britain we knock back around 95 million cups of coffee and 100 million cups of tea every day. That’s alongside close to 670,000 tonnes of chocolate per year – that’s 11kg per person, or three bars every single week.

Meanwhile, newer confections like the high caffeine energy drink have become hugely popular too. Our veins flow with caffeine, and many of us struggle to face the day without our morning dose of the good stuff.

But let’s start at the beginning.

Just what is caffeine?

Caffeine is a stimulant – that won’t be news to anybody. More specifically, it is a psychoactive stimulant, meaning it affects the central nervous system, and as such it meets the technical definition of a drug. Caffeine is, in fact, the world’s most widely consumed psychoactive drug.

Caffeine is a phytochemical – a chemical produced by a number of plant species for two principal reasons:

1. To kill predatory insects that might want to eat them. It’s startling to think that every time you have a cosy cup of tea you’re consuming an insecticide, albeit a completely natural one.
2. To prevent the sprouting of seeds from neighbouring plants that would otherwise compete for sunlight and water.

In human beings caffeine works by temporarily blocking the absorption of adenosine, a chemical compound that triggers drowsiness. This increases alertness and focus. 

Caffeine also has a number of physical effects: it delays muscle fatigue and boosts strength, improving our general stamina, increasing fat burn and improving performance in endurance sports like cycling and running. It also increases our metabolic rate, speeding up reaction times and accelerating our digestive systems.

Caffeine consumption has also been linked to improvements in long term memory and even to a lower risk of developing such serious conditions as cirrhosis, skin cancer, and Alzheimer’s Disease.

As with other psychoactive substances, heavy use of caffeine can lead to the development of tolerance over time, and when you find that cup of black coffee that once jolted you awake in the mornings is no longer quite doing the trick, you may be tempted to increase your caffeine consumption still further. But proceed with caution.

What contains caffeine?

As many as 30 different plant species in Asia, Africa and South America produce caffeine in their leaves, fruit and seeds. But the vast majority of the caffeine we eat and drink comes from the big three:

1. The tea plant – Camellia sinensis – a native of East Asia.
2. The cocoa or cacao tree – Theobroma cacao – an evergreen tree native to central America.
3. The coffea plant, a flowering shrub native to tropical regions of Africa and Asia. Two species – Coffea arabica and Coffea canephora – account for the great majority of global coffee production.

Caffeine sensitivity

Of course you can have too much of a good thing. Not everyone responds to caffeine in the same way. While most people experience moderate sensitivity and become more tolerant over time, some people are highly tolerant from the start, thanks to a particular pattern of genes.

Similarly, some people are especially sensitive and cannot consume even small amounts of caffeine without experiencing a range of unpleasant symptoms. This is called caffeine intolerance or caffeine hypersensitivity. Caffeine intolerance symptoms can include:

• Headaches
• A racing heart
• Jitteriness and restlessness
• Feelings of anxiety
• Difficulty sleeping

Caffeine sensitivity can be genetic or it can be triggered by differences in liver function. People with this condition metabolise caffeine more slowly and experience the effects more intensely.

As with other sensitivities, it can be difficult to establish whether caffeine or some other food is triggering your symptoms. A food intolerance test can be a big help, bringing clarity to sometimes fuzzy and uncertain symptoms.

If you do uncover a sensitivity to caffeine, you will need to get into the habit of reading product labels carefully – but it may be best to phase caffeine out slowly rather than going cold turkey straight away. Like other psychoactive substances, sudden cessation can trigger withdrawal symptoms. The good news is that there are many tasty and satisfying alternatives to caffeine available. Why not explore, for example:

• Herbal teas
• Decaffeinated coffee
• Decaffeinated tea
• Caffeine-free sodas
• Coffee substitutes

You may not find such products on the shelves of every supermarket but most health food stores will offer a good selection. Alternatively, online retailers are plentiful.