For many of us a cup of coffee is such an ingrained part of our morning routines that it’s hard to imagine a day without it. For those of us in this camp, we’re entirely reliant on that first cuppa providing us with a boost of caffeine, quickly increasing our alertness and energy levels. And there are a lot of us! 

In fact, coffee, along with tea, is one of the most widely consumed beverages in the world and part of the routine of about 85% of Americans - who, on average, have about 1.5 cups of coffee a day. (Meanwhile, Europe accounts for around one-third of global coffee consumption.)

Much more than caffeine

This habit goes beyond a simple energy boost. In a more basic form than those complex barista beverages, coffee has been around and consumed for hundreds of years. With its unique sensory characteristics and flavor, coffee has long been a part of our culture and even our social lives. Coffee as we know it - an infusion from roasted and ground beans - is thought to have originated in Yemen, first produced in the 14th century. (A far cry from today’s drive-through vanilla frappuccino with an extra everything drizzle!) 

Around 70 species of the coffee plant, Coffea Rubiaceae, have been identified - with Arabica and Robusta coffee being the most commonly consumed. All varieties of the coffee plant produce a complex drink which contains thousands of bioactive compounds, that are not limited to caffeine. There’s also diterpenes, chlorogenic acid, and many others that provide antioxidant and anti-inflammatory effects.

Interestingly, recent studies indicate that hot and cold brew coffees have some differences, particularly in the total antioxidant capacity, with cold brews presenting a better antioxidant profile. 

…And now, a quick plug for kencko's instant iced lattes

With delicious flavors to choose from, kencko iced lattes can help kick-start your mornings with organic coffee beans and a sweet, full serving of organic fruit. With no added sugars it also provides some fiber to help your gut to function smoothly.

Whether you’re running out the door in the morning or rushing through thousands of meetings at work, it can certainly be a better option than just having caffeine alone on an empty stomach, especially when prepared with a milk of your choice, giving you a greater nutritional content.  

Caffeine and the nervous system

But let’s get back to the main reason so many of us reach for a cup of coffee first thing in the morning. Caffeine is a central nervous system stimulant, and the most widely consumed in the world. It is quickly absorbed in the gut and is able to cross into the brain.

It works on the central nervous system by slowing down the action of a naturally occurring compound called adenosine, which normally causes drowsiness, while also triggering a release of adrenaline, the ‘fight or flight’ hormone. This explains why we often associate coffee with reduced feelings of fatigue and increased alertness. (Or when we overdo it, anxious jitteriness!)

It’s these effects of caffeine that contribute to its habit-forming nature.

Caffeine and the gut

One occasionally inconvenient aspect of the effect of caffeine has to do with what we will politely refer to as “gastrointestinal motility.” There’s a part of the nervous system that’s responsible for the gastrointestinal motor function allowing the progression of content through the gut. 

This is all a fancy way of telling you something you probably already knew at some level: coffee, either caffeinated or not, seems to increase this motor function, promoting the urge to… well, poop. That’s the case at least for one-third of the population, and it’s especially prevalent for women. For some highly sensitive types, this increase in motility can occur as soon as four minutes after drinking coffee, caffeinated or not. So be sure to keep a mental map handy of nearby public bathrooms if you’re taking your coffee to go. 

Health benefits

In terms of effects you might not feel in your brain or butt, coffee contains hundreds of biologically active phytochemicals, including polyphenols. Polyphenols have strong antioxidant properties both in decaffeinated and regular coffee, with regular coffee being twice as potent. In fact, it’s one of the greatest sources of antioxidants in the human diet and the primary source for many Americans.

The protective effects of antioxidants have numerous potential health-promoting properties that have been studied in the cardiovascular and nervous systems, and can help lower the risk of developing degenerative diseases such as Alzheimer’s and Parkinson’s. According to a 2016 meta-analysis, drinking coffee in moderation - 1 or 2 cups a day -  is associated with a lower incidence of cognitive disorders. 

Why are some people more sensitive than others?

While some people seem to be fine with 2 or even 3 cups of coffee a day, for others even a single cup can be enough to give them the jitters. There could be various reasons for this. 

Caffeine blood levels peak after 15 minutes to 2 hours of consumption, but this is subject to large variation from one person to another, based on factors like gastric emptying time and the presence of other food components. Other variables include:

• Food and food components, such as fiber and carbohydrates, can delay how quickly caffeine peaks in the blood. According to a 2013 randomized controlled trial, consumption of a high carbohydrate meal significantly slowed the appearance of caffeine in the blood and also reduced peak concentrations compared to a fasted state. The takeaway here? Drinking your morning coffee on an empty stomach might not be a great idea for people who are more sensitive to caffeine!

• Caffeine clearance rates are also affected by environmental and physiological factors such as the use of oral contraceptives, smoking, and pregnancy. 

• Genetics plays a critical role in influencing caffeine metabolism. There is likely considerable individual variation in the conversion of caffeine to paraxanthine (a metabolite of caffeine), and because paraxanthine also stimulates your nervous system, this would be a factor for differences in response to caffeine.

• Lastly, tolerance to some of caffeine's physiological effects can develop with continued use, so if you are not used to drinking coffee it’s a good idea to start slowly if you’re ready to explore the exciting world of caffeine. 

Avoiding the caffeine crash

Now let’s really get into just why we sometimes feel even worse after a few hours of our coffee buzz. A caffeine crash, characterized by increased fatigue and sleepiness, is something many people experience after its stimulating effects wear off. 

Suddenly stopping all caffeine consumption over the timeframe of a day or two can lead to more intense withdrawal symptoms, including headaches, irritability, fatigue, decreased alertness, and depressed mood in some cases. 

But these can be reduced by gradually decreasing the caffeine dose. If you’re looking to scale back, you could start by not having coffee on an empty stomach if it’s something you usually do, as we have seen that this can reduce peak concentrations of caffeine. 

How much is too much?

When it comes to determining how much caffeine is too much for you, there are a few aspects to consider. 

We know that caffeine helps us feel more awake, so it should come as no surprise that caffeine consumption later in the day can disrupt and reduce sleep quality. Plus, caffeine can induce anxiety, particularly at high doses and in those already predisposed to experiencing anxiety.  Other side effects of high caffeine doses include restlessness, muscle tremors, and a rambling flow of thought and speech.

Limits of 400 mg of caffeine per day for adults and 200 mg per day for pregnant and lactating women have been recommended. This corresponds to about 4 and 2 cups of coffee respectively, but you should also keep in mind other sources of caffeine coming from your diet.

Caffeine content in some foods: 

• 1 cup coffee = 95mg

• 1 shot espresso = 65mg

• 1 cup black tea = 47mg

• 12 oz soda = 40mg

• 1 ounce dark chocolate = 24mg

Those 400 or 200mg levels can sneak up on you if you’re a habitual coffee drinker who enjoys a casual bit of lunchtime chocolate!