Caffeine is the most commonly used mood-altering drug in the world, and coffee is one of the most popular means of ingesting it. Over 50% of Americans drink coffee on a daily basis, and that figure is thought to be increasing every year.
But there’s more to coffee than its caffeine content, and scientists are perpetually trying to make sense of the various effects that this mysterious brew has on our bodies. Coffee’s most recent brush with media attention came just a few weeks ago, with the release of a study that showed women who drank four cups of coffee per day had a 20% lower risk of depression than those who drank a cup or less per week. But coffee isn’t always billed as a wonder beverage; caffeinated and decaffeinated versions alike have built up a pretty serious rap sheet over the years. But, our daily brew does more to our bodies than affect our sleep.
The chemical drip down affects everything from our eyes and lungs, our bowels and brainpower. Here is how.
Compounds in coffee kickstart the waste removal process making us want to go to the loo – sometimes as quickly as five minutes after our first sip.
This is good if we have our coffee after food. It sparks our digestion by stimulating the acid levels in the stomach. Drinking on an empty stomach however can irritate the gut lining, causing discomfort and bloating.
Coffee opens our lungs making it easier to breathe and slightly raises blood pressure slowing down the heart (although drink too much and you will notice it has the opposite effect).
We’ll also notice a fairly immediate spike in energy, but only for about three hours before the effect fades and we can experience a caffeine come-down.
“This is because the caffeine in coffee doesn’t actually make you more energetic, it just makes you less able to feel that you’re tired,” Dr Owen Bain tells The Telegraph, London. “So unless you are well rested you will start to feel tired again.”
Within half an hour of drinking a cup, our brainpower gets a boost as the caffeine sharpens our concentration and our eyesight as the adrenaline dilates our pupils.
“Caffeine is a stimulant and 20 minutes after drinking a coffee you can start to feel more alert, with increased concentration, and are less likely to make mistakes,” Bain says. “A recent study showed that coffee could enhance your memory 24 hours after consumption. This may not appear to be long, but most memories are lost within a few hours after learning.”
One to 12 hours:
Our mood lifts within the first hour.
“An hour after drinking coffee there is a reduction in anxiety levels and increased feelings of contentment,” Dr Bain says. “Women who are regular coffee consumers have been shown to have less depression.” That said, Bain notes that too much coffee causes anxiety. Your espresso – and its effects – has more staying power than you might imagine, Bain says. “A single cup of coffee has rapid absorption with caffeine uptake to the blood in just over 20 minutes and will stay in the bloodstream for over 12 hours.”
Coffee doesn’t just keep you awake, it may literally make you smarter as well. The active ingredient in coffee is caffeine, which is a stimulant and the most commonly consumed psychoactive substance in the world. Caffeine’s primary mechanism in the brain is blocking the effects of an inhibitory neurotransmitter called Adenosine. By blocking the inhibitory effects of Adenosine, caffeine actually increases neuronal firing in the brain and the release of other neurotransmitters like dopamine and norepinephrine. Many controlled trials have examined the effects of caffeine on the brain, demonstrating that caffeine can improve mood, reaction time, memory, vigilance and general cognitive function.
There’s a good reason why you will find caffeine in most commercial fat burning supplements. Caffeine, partly due to its stimulant effect on the central nervous system, both raises metabolism and increases the oxidation of fatty acids. Caffeine can also improve athletic performance by several mechanisms, including by mobilizing fatty acids from the fat tissues . In two separate meta-analyses, caffeine was found to increase exercise performance by 11-12% on average.
Not only can coffee make you smarter in the short term, it may also protect your brain in old age. Alzheimer’s disease is the most common neurodegenerative disorder in the world and a leading cause of dementia. In prospective studies, coffee drinkers have up to a 60% lower risk of Alzheimer’s and dementia . Parkinson’s is the second most common neurodegenerative disorder, characterized by death of dopamine-generating neurons in the brain. Coffee may lower the risk of Parkinson’s by 32-60%.
Numerous studies have pointed to a correlation between coffee consumption in pregnant mothers and an increased likelihood of miscarriage. One of the more recent — and arguably most thorough — of these studies was published in 2008 in the American Journal of Obstetrics and Gynecology, and found that the risk of miscarriage is more than double in women who consume over 200 mg or more of caffeine per day. 200 mg/day is also the upper caffeine limit recommended by the American College of Obstetricians and Gynecologists.
Shortly after drinking coffee, your blood pressure rises a fraction – the effect is more pronounced if you don’t drink coffee regularly. If you stick to one cup, your heart rate actually slows down due to the increase in blood pressure. “However, more than a few cups of coffee can cause heart rate acceleration,” Dr Bain says. For healthy people this is not a problem, but may be an issue for those with underlying problems such as heart disease, high blood pressure or abnormal heart rate, according to some experts.
Even though coffee in moderate amounts is good for you, drinking way too much of it can still be harmful. I’d also like to point out that many of the studies above were epidemiological in nature. Such studies can only show association, they can not prove that coffee caused the effects. To make sure to preserve the health benefits, don’t put sugar or anything nasty in your coffee! If it tends to affect your sleep, then don’t drink it after 2pm. At the end of the day, it does seem quite clear that coffee is NOT the villain it was made out to be. If anything, coffee may literally be the healthiest beverage on the planet.