What is it caffeine?
We are all familiar with caffeine, but its history and effects are a tale both fascinating and surprising to tell. Let’s start by saying that caffeine is a substance naturally found in many foods and beverages. The most common sources in our diet are tea and coffee, but also mate, guarana and cocoa contain significant amounts. We all know and often appreciate caffeine for its stimulant properties, in particular for its capacity to help focus and avoid sleepiness. Its impact on our physiology is so profound that caffeine managed to carve a mark in history that roots back to ancient times. There is abundant evidence of coffee being concocted in Arabia, cacao forming a part of daily diets in South America, and tea being part of social rituals in ancient China. In antiquity, its effects were swathed in myth and legend precisely for its brain-boosting properties and powers.
It wasn’t long before the appeal of these natural substances had spread across the globe. Two billion cups of coffee are consumed every day and it has been argued that caffeine itself has managed to change the course of human history itself. In “Caffeine: How coffee and tea created the modern world” Michael Pollan explores how caffeine has been decisive in winning and losing wars, in changing politics, and how it shaped our economies. This might sound like an exaggerated claim, but if we consider how since the Industrial Revolution the rhythm of our lives has accelerated in parallel with the development of a model based on ever increasing production rates, it becomes clear that it’s not a coincidence that caffeine is so commonly used. To this point, Pollan affirms that the Industrial Revolution itself “would have been very unlikely to take place without it (caffeine)” precisely for the ability of caffeine to stimulate us, while increasing our motivation, focus and drive.
This being said, it’s very possible that most of these billions of coffee cups (plus all the other caffeinated beverages and foods) are consumed without a clear understanding of how caffeine works and what are its effects on our health.
So how does caffeine do its magic?
Let’s start by saying that caffeine’s effect depends on the amount taken and on our tolerance, or lack thereof. These are quite complex processes, let’s just say generally speaking more caffeine means a stronger effect and less means a smaller one. In regards to tolerance, the rule of thumb is the more you regularly drink caffeine, the more you will need over time to get the same effect.
Now let’s get to the juice: how does caffeine make us feel the way it does? The very mechanism by which it stimulates us and makes us less tired is triple. The first mechanism sees caffeine inhibiting the Cyclic AMP Phosphodiesterase pathway, which allows cells to “stay active” and stimulated longer. Secondly, caffeine acts as a competitive antagonist of Adenosine, a neurotransmitter that relaxes the brain and makes us feel tired. Normally, adenosine builds up across the day increasing a sort of “sleep pressure”, but in the presence of caffeine our brain does not perceive this pressure and this allow us to feel steadily awake, even after a shorter night of sleep or late into the evening. Thirdly and finally, caffeine activates noradrenaline neurons, acting on serotonin neurons and affecting the local release of dopamine. This is the central mechanism that underlies our experience of increased alertness, motivation and focus after a cup of coffee or tea.
The first two mechanisms are the ones keeping us awake and energetic, the third allows us to feel focused and motivated during the day and therefore get things done, respect deadlines and be productive. These three mechanisms combined also allow caffeine to act as an ergogenic substance, reducing our sense of fatigue and increasing our physical performance.
A final consideration has to do with motivation: caffeine seems to have the ability to increase dopamine release up to 30%, while increasing the density of dopamine receptors in the Striatum, an area of the brain involved in planning and action. This allows us to experience the effect of dopamine more strongly, making activities for which we are already motivated feel even more motivating when caffeine is around.
If it’s true that for most of us this ability of caffeine to help us get through the day is something we appreciate and (frankly) count on, it’s also true that anything that exerts such power on or physiology should be consumed carefully. Knowing how much, why and from which are the sources in our diet.
This leads to two different points. First, after all the positives, let’s talk about the not so positive. And second, why is there no caffeine in our Good Cola?
Let’s start from exploring why people associate caffeine with sodas.
Of course the simple answer would be: because sodas typically contain caffeine. And yes, if this is clearly true lets’ then ask ourselves why. Why do sodas contain caffeine?
First, caffeine naturally has a bitter taste to it and soda companies have always claimed that its bitterness is the main reason for the addition of caffeine to their drinks. The idea is that caffeine complements sweeteners used in beverages. In most cola products, for example, that bitterness is actually used as part of the taste, partly to counter the sweetness, and partly because it adds to the unique cola taste. This all started when every cola tasting soda did contain kola nut extract as part of the ingredients. Soft drink manufacturers like Coca-Cola included the extract of the kola nut in their recipe, and caffeine is naturally present in the kola nut.
Nowadays, on the other hand, this natural source of caffeine is out of fashion and to replace what was once a natural taste synthetic caffeine is added to compensate and invoke the missing flavor of the kola nut. This, at least, is the official reason provided by soft drink manufacturers. In 1980, the US Food and Drug Administration proposed the elimination of caffeine from soft drinks. Soft drink manufacturers responded that caffeine is included in the drinks to impart the requisite flavor and therefore indispensable.
For as much as this is the official reason, there seems to be a more compelling one, and yes, you guessed it, it’s got to do with caffeine’s powerful effects we described above. A few research studies have been conducted, one just before the turn of the century and the other a decade ago, indicating that the claim of caffeine imparting flavor may actually be false. The study by Griffiths and Vernotica used beverages containing a range of caffeine concentrations in their research and found that the test subjects detected the presence of caffeine more frequently as the caffeine concentration increased. Interestingly, only 2 subjects (8%) were able to detect caffeine when it was present in an amount that was normally found in caffeinated soft drinks. They therefore concluded that this result did not support the claim that caffeine imparts flavor to soft drinks.
A more recent study by Keast and Riddell used sweeteners as controls, so that caffeine concentration remained constant, at a similar amount to that found in cola soft drinks. The researchers found that their test subjects were able to distinguish between caffeinated and non-caffeinated sweeteners, but none of them were able to make the same distinction between caffeinated and non-caffeinated cola beverages. This led them to a similar conclusion as the previous study – that caffeine has no meaningful flavor activity in soft drinks.
These conclusions bring us back to the most probable hypothesis: people consuming caffeinated sodas are used to get a similar buzz to the one a coffee or a tea would provide, which would not only make them more attentive, but also possibly improve their mood. Perhaps the combination of high sugar levels in fizzy soda, along with the small amount of caffeine they contain, could give drinkers the “pick me up” they desire and make them choose that beverage again at the following occasion.
Now, there’s nothing wrong with this (apart from the lie about the taste), but if we want to avoid exaggerating with caffeine, let’s make sure we account for the one present in sodas. The caffeine contents of Coke, Pepsi and Mountain Dew: 34 mg, 38 mg and 54 mg, respectively. These are figures for a 350 ml (12 oz) can. This is important to remember because there is scientific evidence showing that withdrawal symptoms can arise after staying away from a daily dose of only 100 mg of caffeine, which means that drinking 3 cans of Coke or Pepsi and 2 cans of Mountain Dew a day is enough to build tolerance to caffeine and feel like crap when lacking.
Another cautionary note is due about the caffeine in sodas. It’s synthetic and it’s isolated. Let’s deal with one thing at the time. Natural caffeine is typically burned out from coffee beans, but the one found in sodas is produced in Chinese pharmaceutical plants. Surprisingly, its production started in the 1800s and production ramped up with the Nazis during WWII. Embargoes prevented them from obtaining various goods (natural caffeine included), and a synthesized version was created to keep supplies available. With demands for caffeine steadily rising since then, synthetic caffeine has since become the norm, especially in soda and energy drinks. Today, many consumers are unable to identify where the caffeine in their food has come from - or are even aware that a synthetic version exists. Needless to say that synthetic caffeine is cheaper to produce than it is to source natural ingredients, and consequently, it is the standard in bottled beverages. This is not to suggest that this makes it worse in some way, synthetic and natural caffeine are nearly indistinguishable; both are chemically identical. The major difference is that synthetic caffeine is produced from urea and chloroacetic acid rather than extracted from plant products like natural caffeine. Still, we think it’s good to know when choosing a product.
To understand where the real difference lies in regards to synthetic caffeine, we have to look at the effect it has when it’s not ingrained in the plant matrix it’s naturally found in. Naturally, caffeine is typically present together with a range of vitamins and methylxanthines also found in the plant (coffee is a good example of this). These vitamins and methylxanthines balance the lift and fall of the caffeine in your system and assist in delivering it to your body in a steady manner. This promotes a more sustainable energy boost than synthetic caffeine does, enabling mental clarity and focus for a longer period. A sustained release of caffeine can prevent sudden jitters and subsequent crash commonly associated with synthetic caffeine products like energy drinks. Because of this more gradual release, natural caffeine instigates side effects such as nervousness, difficulty sleeping and a flushed face nearly as much as synthetic caffeine.
This leads us to the main reason for why we think it’s meaningful to know if a beverage contains caffeine and to consider this when choosing one: caffeine’s possible side effects. We have seen how caffeine is a mildly addictive, mood-altering substance. We haven’t discussed the general recommendations for caffeine and its effect on pregnant women, kids and on our sleep.
If it’s true that here is no recognized health-based guidance such as an Acceptable Daily Intake when it comes to caffeine, the general recommendation for adults is to consume no more than 400mg of caffeine per day (from all sources in the diet). Beyond this limit caffeine can provoke a long list of side effects, such a jitteriness, restlessness, tremors, anxiety, heart palpitations, irregular heartbeat, trouble sleeping, headaches, migraine, high blood pressure, dehydration and exacerbate both acidity in the stomach and panic attacks. The dose makes the poison, unsurprisingly.
In regards to pregnancy, the daily limit is 200mg, beyond which caffeine is known to become dangerous. Some publications suggest that the limit should be 0mg as there is no benefit to its consumption and therefore the risks outweigh the benefits. Caution is also recommended to breastfeeding women, different limits are set in different parts of the world but the least the better is their common theme.
For what concerns kids, caffeine is mostly counter indicated. Because of the dose-response effect the smaller body size of children results in less caffeine having a greater impact on their functioning. Children and adolescents are also still developing and the impact of caffeine on their nervous systems and cardiovascular systems is not fully known. Too much caffeine can cause issues such as increased anxiety, increased heart rate and blood pressure, acid reflux and sleep disturbance. Too much caffeine is dangerous for kids, and in very high doses, can be toxic. Again, 0mg is the best amount and if a child feels like the need to consume caffeine to get through the day, it’s recommended to work with a pediatrician to identify the root cause of what is creating the fatigue in the first place. This being said, safety upper daily limits have been set depending on the age group. These are as follows: for ages 4 – 6 is 45 mg (about a half cup of coffee), for ages 7 – 9 62.5 mg, for ages 10 – 12 85 mg, and for adolescents the maximum range is 85 – 100 mg.
Coming to sleep, this is an interesting topic. If you recall, caffeine is a competitive antagonist of Adenosine, a neurotransmitter that relaxes the brain and makes us feel tired. In poor words, caffeine hits the “mute button” on sleepiness, making us feel alert even when we are tired or sleepy. This of course implies that we can stay wake longer instead of going to sleep if we consume caffeine close to our sleep time, or we end up feeling too awake when we would like to fall asleep. For as much as not managing to fall asleep because of the wrong timing or dose of caffeine can be unpleasant, this is something we can feel and therefore regulate. It’s under our control so to say. If one day we feel too awake at night, the following day we can simply anticipate our last consumption of caffeinated foods, reduce their dose or avoid them altogether. If this sounds simple and un-problematic, know that there’s a catch. The catch is that the effect of caffeine on sleep is not as binary as we might think. Caffeine can silently and unperceivably change the architecture of our sleep for the worst. The typical example of this is someone reporting “I can consume caffeine at any time, even at night before bed, and I still sleep like a baby”. Well, data from scientific studies would disagree. Let’s first discuss the length of time caffeine stays active in our system and then quickly look at some experiments to get a sense of the scope of the problem.
Caffeine has a half-life of about six hours, in other words…after six hours, 50% of the caffeine is still in our brain. And a quarter life of 12 hours, therefore after 12 hours, 25% is still there. So if we had a cup of coffee at noon… a quarter of that caffeine is still in our brain at midnight. If we wanted to completely eliminate the effect of caffeine when we go to bed at night we should probably stop consuming it about 12-14 hours before that time. We know, this does not sound very realistic, but it gives us some numbers and time to keep in mind when making our choices with caffeine. It definitely suggests that it would be wise to avoid caffeine too close to bed. This is important as it has been shown that 200 mg of caffeine before bed resulted in a 20% reduction in deep sleep. In life, aging by 25 years would be needed to get the same drop. This applied also to people who say they sleep just fine after consuming caffeine. They don’t perceive the effect and can fall asleep without latency, but even if they can get the same “quantity” of deep sleep, it doesn’t mean their quality isn’t negatively affected.
In poor words, when referring to sensitivity, we’re talking about pure “wake promotion”. This seems to be a totally separate measure when compared to how it affects the structure of our sleep. And getting enough deep sleep is a requirement for the consolidation of our memories, for the restoration of executive function and to allow the brain to be prepared for future learning and memory formation. Moreover, deep sleep seems to be the best blood pressure medication available, while also preventing accumulation of proteins associated with neurodegenerative disease. These mechanisms of wrongly-timed caffeine are known to interfere with the reduction of deep sleep.
We now think the stage is set to discuss why our Sodas don’t contain caffeine. Put simply: because we just don’t see a reason to add it to our recipes. Our recipes don’t require it for taste and we don’t believe that its effect would increase the desirability of our products. On the contrary, we think that our caffeine-free sodas will be better companions for our drinkers. Moreover, we have no intention of excluding pregnant women or kids from enjoying a soda when they want one, and we don’t want to interfere with anyone’s sleep if a soda is enjoyed late in the day.