Caffeine was first chemically isolated in a German laboratory in 1819. It is an alkaloid, as is cocaine, that occurs naturally in some 60 tropical plant species, of which cocoa beans, tea leaves and coffee beans are the most well-known.
When coffee leaves die and fall to the ground, they contaminate the soil with caffeine, which makes it difficult for other plants to germinate; it acts as a natural herbicide. But coffee plants mainly use caffeine as an insecticide. It can be toxic to insects and they tend to avoid it. But coffee plants also lace their nectar with low doses of caffeine. When insects feed on the nectar, they get a buzz that makes them more likely to revisit the flower and spread its pollen.
It’s not just bees that get their buzz from caffeine. In his book All About Coffee, William Ukers writes that the French writer Balzac was a big fan, drinking a reported (but scarcely credible) 50 cups of coffee per day. In his Treatise on Modern Stimulants, Balzac describes the effect that caffeine had on him:
‘This coffee falls into your stomach, and straight away there is a general commotion. Ideas begin to move like the battalions of the Grand Army on the battlefield, and the battle takes place. Things remembered arrive at full gallop, ensign to the wind. The light cavalry of comparisons deliver a magnificent deploying charge, the artillery of logic hurry up with their train and ammunition, the shafts of wit start up like sharpshooters. Similes arise, the paper is covered with ink; for the struggle commences and is included with torrents of black water, just as a battle with powder.’
The author Mathew Walker is less of a fan. In his book Why We Sleep: The New Science of Sleep and Dreams, he describes caffeine as ‘the most widely used (and abused) psychoactive stimulant in the world…It represents one of the longest and largest unsupervised drug studies ever conducted on the human race, perhaps rivalled only by alcohol, and it continues to this day.’
When caffeine hits your brain, it adheres to your brain’s adenosine receptors. Adenosine is what helps us feel sleepy. When caffeine binds to your adenosine receptors, it inactivates them and stops you from feeling tired. Caffeine tricks us into feeling alert and awake despite the high levels of adenosine that would otherwise make us sleepy.
Caffeine is removed from our system by an enzyme in our liver that gradually degrades it over time. Caffeine has an average half-life of five to seven hours: after five to seven hours, about 50 percent of the caffeine you have drunk is still circulating in the body. So, if you enjoy an espresso at 10pm after dinner, as I used to do when I was younger, then half of the caffeine will still be in your brain at 3am.
Some people have a more efficient version of this enzyme than others, allowing them to clear the caffeine quicker. Others have a slower, less efficient version. Unfortunately, aging affects the enzyme’s efficiency: the older we get, the longer it takes to clear our brains of caffeine.
Just because the caffeine is stopping our brain from processing the adenosine, it doesn’t mean the brain stops producing it. When the caffeine inevitably wears off, you’re left with an adenosine build-up which makes you feel even more tired – what is commonly known as a ‘caffeine crash.’
The good news is that roasted coffee does not just contain caffeine; it is full of biologically active compounds like chlorogenic acid, kahweol, and N-methylpyridinium, all of which have been found to reduce inflammation, serve as potential anticancer mechanisms, and improve insulin sensitivity.
In 2017, a review on coffee consumption and human health in the British Medical Journal examined more than 200 previous studies and found that moderate coffee drinkers had less cardiovascular disease and premature death from all causes, including heart attacks and stroke, than those who didn’t drink coffee.
The latest scientific view, as published in the World Cancer Report 2020 confirms that coffee is full of antioxidants that reduce the risk of certain cancers – such as liver and endometrial cancer. The report, published by the International Agency for Research on Cancer (IARC), part of the World Health Organisation, is a collaboration between the world’s most prominent scientists, and is considered the authoritative source on cancer related disease.
The National Institutes of Health (NIH) – part of the US Department of Health and Human Services – has conducted a study of 400,000 people that confirmed that moderate coffee drinking lowers the risk of death overall. The study found that relative to men and women who did not drink coffee, those who consumed three or more cups of coffee per day had approximately a 10 percent lower risk of death. The leader of the research team wrote,
‘We found coffee consumption to be associated with lower risk of death overall, and of death from a number of different causes. Although we cannot infer a causal relationship between coffee drinking and lower risk of death, we believe these results do provide some reassurance that coffee drinking does not adversely affect health.’
© Commodity Conversations ®
This a short extract from my upcoming book Coffee Conversations – Crop to Cup to be published later this year.