What does the research say – why may coffee be so beneficial?
The recent headlines you may have seen bigging up coffee, are the result of a large-scale European study which has been recently published online.1
The study was a prospective cohort study, meaning it involved recruiting people – half a million to be exact – and following them long-term, for a set period of time (16 years). The researchers take a topic of interest into account – if people drink coffee or not – and they then assess who reaches the end of the study in good health, and who isn’t so lucky.
The findings were quite definitive (or so it seems): those who drank coffee, and the more coffee the greater the effect (up to four cups per day), had a significantly lower risk of death. This was the case for all-cause mortality (all cases of death) and significant effects were also found for specific causes of death including those from digestive diseases in both men and women, and also death from circulatory diseases and cerebrovascular diseases (for example stroke) in women specifically.
So, the results certainly looked promising, but should we all be rushing out to stock up on our coffee just yet? Let’s just have a look at some of the flaws this study may have, and some of the finer details, before we all jump to conclusions.
What do we need to consider – are the findings that clear cut?
Although the results seem promising, now I’m going to delve a little deeper. See, we don’t often recommend coffee here at A.Vogel and Alfred Vogel wouldn’t let the stuff anywhere near his clinic! His intuition was incredible so we’re right to be a little sceptical.
Firstly, I want to consider the study in a little more detail, which isn’t always easy, but there are a few little imperfections I would just like to flag up.
The study was conducted over 16 years as I’ve mentioned, but the participants were only asked once at the very start of this study about their coffee-drinking habits... 16 years is a long time for habits to change – as I’m sure many of you will agree! So this isn’t ideal.
Next, there could have been some confounding factors going on here. This means, external factors that aren’t the sole aim of the study, having an impact. Although a special statistical analysis called a multivariate analysis was carried out, this doesn’t take all factors into account and some confounds can slip in. Smoking, for example was identified as a possible confounding factor and taken into consideration, good, but other factors like income and social factors weren’t.
So, someone with lots of money, but drinking coffee, may actually be spending their money on lots of other health promoting activities such as supplements or a personal fitness advisor (who knows what!). So, this could definitely be classed as a confound. Next, there is the social aspect. We know that people who are lonely or experience traumatic events are more likely to be stressed and as a result risk living shorter lives – so this is one too.
Also, this type of study isn’t the ‘gold standard’ method when it comes to research trials, ideally we would like to assign people randomly to a group (coffee drinking or not) and ensure they continually drink coffee three times a day for the next 16 years – known as a randomised control trial. But obviously that isn’t possible. So, there are also going to be flaws to a certain extent with this type of study design.
Still though, considering what the results of the study highlighted, it showed that similar benefits were found with both decaffeinated coffee and the regular caffeinated varieties. This is interesting, as it suggests the caffeine isn’t exerting the proposed benefit – but most likely the other bioflavonoids and naturally occurring compounds in the coffee bean instead. This is not surprising really – it’s a plant after all!
In the small print though, the conclusions drawn from the authors were that we shouldn’t jump to conclusions just yet, which is good. The authors admit that coffee is complex and contains a number of different substances that may or may not be beneficial to health, although, overall there seemed to be no adverse risks to health as a result of drinking coffee.
Just on a side note, it was also concluded that female coffee drinkers did face a significantly greater risk of dying from ovarian cancer than the non-drinkers, so, not such good news for women it seems.
What should we take from this?
In light of this new research I’d still be very wary of recommending people drink copious amounts of coffee daily – 3-5 cups per day and up to 400mg / day of caffeine is pretty astronomical and if you’re fitting in that amount of coffee, let’s not forget it’s unlikely you’re keeping up with your recommended daily water intake – no coffee doesn’t count!
It may well be the case that the antioxidants in coffee are super healthy, which makes sense, as antioxidants come from plants and generally are! But when teamed with a high caffeine element, perhaps we should be a little more wary. There is research to suggest that a high consumption of coffee has links with sleep issues2 and blood sugar dysregulation3, and these two issues themselves have a number of long-term health implications.
Caffeine stimulates our sympathetic nervous system and what we call our fight or flight response (also known as our stress response). Caffeine stimulates the release of adrenaline and cortisol (stress hormones) from our adrenal glands which makes sugar more readily available in the blood stream – so you have the energy to take on that stressor! But often, as we know in hectic modern lives, there often isn’t actually a physical stressor, so this isn’t technically a true stress response. Unnecessary over-stimulation can cause us issues longer-term such as adrenal fatigue and leave us feeling tired and well, stressed out, unsurprisingly. So in conclusion, caffeine is a stressor to the nervous system – menopausal women suffering from hot flushes can vouch for this as it’s a common trigger.
My advice for now would be to get your antioxidants from elsewhere – colourful fruit and vegetables which we can all agree are beneficial for our health, and herbal teas too, as they are much lower in caffeine but with all the added benefit of antioxidants.
1.Gunter MJ, Murphy N and Cross, AJ et al. Coffee drinking and mortality in 10 European countries: A multinational cohort study. Ann Intern Med, 2017, DOI: 10.7326/M16-2945
2. https://www.ncbi.nlm.nih.gov/pubmed/24235903
3. https://care.diabetesjournals.org/content/27/12/2990
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