I was lecturing today and at one point was exploring some of the adverse effects on health the artificial sweetener aspartame may have with regard to human health (for more about this, see here). One of the attendees was lamenting the fact that she had, for several years, drunk one and a half litres of diet cola a day. She had, mercifully I think, cut this habit out some months ago. I asked her what it was that led to her taking this step, expecting her to mention increasing awareness of the hazards aspartame poses to human health. However, her real motivation turned out to be that she was concerned about what the caffeine in diet cola might be doing to her health.
Actually, out of caffeine and aspartame I generally view the former as the lesser or two evils. But this lady’s focus on caffeine got me thinking about what this stimulant is doing in cola in the first place. You see, according to the manufacturers, caffeine is there because it enhances the flavour of cola beverages. Cola beverages manufacturers for doing extensive taste tests on consumers, so this made me wonder if there was any evidence that caffeinated cola tastes any different or better than non-caffeinated cola.
My search on-line turned up one interesting paper . As part of this research, 30 trained tasters sampled caffeinated and non-caffeinated cola beverages, without knowing which was which. None of them (not one) was able to tell the difference. This wasn’t the biggest sampling exercise ever conducted, but the results were pretty conclusive. Even for trained tasters, the addition of caffeine to cola really doesn’t seem to affect taste.
And if that’s how it is, we can only wonder what caffeine is really doing in cola beverages. The fact that caffeine is a stimulant means that its addition to beverages will help ensure these drinks give individuals a bit of a lift or even positive boost to their energy. Regular cola doesn’t contain, volume for volumne, anything like the caffeine found in energy drinks or even regular coffee and tea. However, it certainly contains enough to give a bit of jolt to some that drink it, and this is especially the case if someone is quite caffeine sensitive. Some individuals have relatively limited capacity to metabolise caffeine in the liver, and can therefore feel ‘wired’ on even quite small amounts of caffeine.
The stimulant effects of caffeine means it has at least some addictive potential. Especially for caffeine-sensitive individuals, withdrawing from caffeine can induce symptoms such as headaches, fatigue and irritability. The discomfort that can come from withdrawal of caffeine will help, of course, to keep punters coming back for more. There is some evidence  that caffeine withdrawal can come on after abstaining from a daily dose of only 100 mg of caffeine per day (about what you’d find in 3 cans of cola).
The fact that caffeine withdrawal can induce headaches reminds me also of the fact that caffeine is a sometime component in headache remedies. Yet, caffeine has no painkilling qualities. In a previous column here. I suggested that caffeine may be in these medications to help with the caffeine withdrawal that may have induced the headache in the first place. However, having a painkiller with caffeine in might sort out a headache, but is also likely to lead to caffeine withdrawal. Which, of course, might induce another headache. And so the cycle may go on.
Part of the reason for writing about this is personal: about 10 weeks ago I withdrew from caffeine. I wasn’t having that much (just some coffee in the morning) but I like a bit of self-experimentation and thought I’d bite the bullet on this. I was a bit chicken about it, and opted for gradual withdrawal (over a week) rather than going cold turkey. I avoided the caffeine withdrawal headache, but I definitely missed the caffeine for the first few days after stopping completely. I have a feeling I was more dependent on caffeine then I realised. My girlfriend recently reminded that before kicking the habit, having coffee in the morning was a real priority for me. That’s gone now. And as a result, mornings are easier for me because I no longer have to wonder where I’m going to get my caffeine/coffee fix from when I’m travelling.
But the main thing change I’ve noticed is that my energy levels are that much more stable throughout the day. This may be placebo response, of course, though it mirrors what I hear from a lot of individuals who have withdrawn completely and successfully from caffeine.
1. Keast RS, et al. Caffeine as a flavor additive in soft-drinks. Appetite. 2007;49(1):255-9
2. Juliano LM, et al. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl). 2004;176(1):1-29