The smell of coffee – do you love it or hate it? Does it get you out of bed in the morning or do you blame it when you can’t get to sleep at night?
Coffee is a central part of life for so many people. We drink coffee first thing in the morning, as soon as we get to work, when it’s time for a break or when we meet up with friends. But is it actually good or bad for us? In fact where does it come from and how did it succeed in infiltrating every part of our society.
I had a vague idea that coffee comes from some kind of plant grown in coffee plantations in hotter countries than ours, and that the active ingredient is caffeine. Having done some reading on the subject it turns out that the history of coffee and tea consumption are really interesting.
Caffeine is a chemical which is found naturally in several plants including coffee beans, cocoa beans, tea leaves and the kola nut (the plant which gives cola drinks their flavour). It can also be produced artificially. It’s classed as psychoactive substance meaning it affects the way we think or feel. Unlike many psychoactive substances it’s legal and unregulated. It’s been estimated that over 80% of the US population consume at least one caffeinated drink each day.
It’s thought that coffee drinking may have originated in Ethiopia. Legend has it a goat herder spotted his goats were full of energy after eating the fruit of the coffee shrub. He tried it himself and found he stayed awake and alert all night, then took some to the local monks to try.
Originally the whole coffee fruit, which looks a bit like a cherry, was made into a drink. In the 13th century people start roasting the beans inside the fruit. Over the years it became a valuable commodity over the world, it spread to Europe and eventually reached the USA in the 18th century.
Like coffee, tea drinking dates backs thousands of years and occurred in different societies. The earliest tea brewing is thought to have been in China. A popular Chinese legend tells us that Shennong, an ancient Emperor was drinking a bowl of boiled water when some leaves from a tree blew into it. They changed the colour and the flavour of the water and he found it to be restorative. Chewing on tea leaves and then brewing of tea became popular within China and trading began in the East.
In the early 17th century, tea was introduced to various parts of Europe. To begin with it was expensive, but over time the price dropped and it became more accessible. By 1750 it was classed as the British national drink.
Tea drinking seems to have a more violent history than coffee. The British used opium produced by colonial India to pay China for tea, creating social problems with opium use in China. Opium trade was banned by China meaning the tea importers could no longer pay China for tea or other Chinese goods like silk and porcelain. It culminated in a war between China and Britain.
The Boston Tea Party in 1773 was no tea party. Britain was imposing large taxes on tea sold to the American colonies. The American colonists felt the taxes were unfair – they weren’t represented at the British Parliament and had no say in the matter. As a political protest the tea cargo from three British ships was destroyed by dumping it in Boston Harbour. Tea drinking then became unpatriotic in America and coffee became increasingly popular.
Why do we like our caffeine so much?
At low to moderate doses caffeine stimulates our brain. It makes us feel more alert and improves our reaction times and attention. It helps us to maintain concentration when performing boring tasks. It improves physical performance for both endurance and high intensity exercise.
The benefits of caffeine increase with the amount consumed until a point. If too much is consumed there is a negative effect on both the brain and on physical performance.
Everyone is different but up to around 300 mg or 3 cups of coffee is thought to optimise performance without running into side effects. Generally higher intake over 400 mg can cause us to feel anxious and jittery.
Examples of caffeine content would be:
- Instant coffee – roughly 100 mg
- Tea brewed for 5 mins – roughly 40 mg
- Starbucks Americano Venti – 300 mg
- Can of Coca-cola – 32 mg
- Can of Diet Coca-cola 42 mg
- Can of Red Bull – 80 mg
- The amount found in chocolate is much smaller
Caffeine is absorbed quickly into the blood stream after consuming it. It’s levels peak after around an hour and drop by about half over the next 3 to 6 hours. You can see why even drinking it fairly early in the evening can still have an impact on sleep several hours later.
Caffeine and our health
It’s not just about caffeine, other compounds in tea and coffee called polyphenols are thought to be beneficial for health. It’s impossible to be definitive about it as it’s notoriously difficult to perform clear cut clinical trials about food and drink but it would seem likely that drinking coffee and tea have lots of potential health benefits.
-Caffeine may help protect against Alzheimer’s dementia and Parkinson’s disease.
-It may reduce risk of heart disease, stroke and heart failure as well as reducing overall risk of death.
-It may improve erectile function.
-There is an association with a reduction in the risk of fatty liver, liver cirrhosis and liver cancer.
However, there are some negatives. The main situation in which higher levels of caffeine should be avoided is in pregnancy. High caffeine intake has been associated with low birth weight in babies, early labour and increased risk of miscarriage. The recommendations are that in pregnancy you should limit caffeine intake to 200 mg. Additionally there is some suggestion that in women it may be associated with increased risk of fractures.
A final downside of caffeine is the potential for symptoms of caffeine withdrawal if you have a high intake of caffeine and you stop drinking it suddenly. The most common symptom is headache. Other symptoms are fatigue, difficulty concentrating, irritability and low mood. Timing of symptoms may vary between individuals but often occur 12 to 24 hours after the last caffeinated drink and may last from a couple of days to over a week.
To summarise, caffeine in it’s various forms has been part of society for centuries. At moderate levels of 400 mg a day or less it appears to be pretty good for you. The caveat to that would be in pregnancy, when the recommended maximum intake is 200 mg.
- Coffee consumption and total mortality: a meta-analysis of twenty prospective cohort studies; British Journal of Nutrition (2014), 111; Je et al
- Coffee consumption and health: Umbrella review of meta-analyses of multiple health outcomes; BMJ 2017: 359; R Poole et al
- CV effects of caffeinated beverages; Trends in Cardiovascular Medicine Voskoboinik et al, October 2018