For me coffee is a topic of interest. To be a tad more accurate, since I consume rather a lot each day, I’m interested in understanding the health impact. Yes, it is once again time for another coffee break. Over the last couple of years I’ve posted a few articles about the latest research on Coffee and it’s impact upon our health …
- In June 2016 I was writing about a study that demonstrated that it was not cancer causing, and was apparently beneficial.
- November 2017 I was writing about a meta-analysis that was published within the BMJ that once again pointed towards it being wholly safe and potentially beneficial (They were not suggesting it to be medicine, but instead confirmed that it was safe).
- July 2018, I wrote about the study that looked at the association of coffee drinking with mortality. Drinking coffee was associated with a lower mortality rate.
- March 2019, there was a study that revealed that Coffee could slow or stop prostate cancer.
- May 2019, brought us a study that addressed the question of how much is too much?
… and so I now have an update. There is some new research that brings us the results of a very long running study that investigated the links between coffee brewing methods and risks of heart attacks and death.
There are many different ways of making coffee, so which is best for your health ?
We do now have an answer. The research results have been published in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).
Let’s take a look.
Paper: Coffee consumption and mortality from cardiovascular diseases and total mortality: Does the brewing method matter?
What Question were the researchers asking?
They wanted to Investigate whether the coffee brewing method is associated with any death and cardiovascular mortality, beyond the contribution from major cardiovascular risk factors
What did they do to get an answer?
Between 1985 and 2003, the study enrolled a representative sample of the Norwegian population: 508,747 healthy men and women aged 20 to 79. Participants completed a questionnaire on the amount and type of coffee consumed. Data was also collected on variables that could influence both coffee consumption and heart diseases, so that these could be accounted for in the analysis. For example, smoking, education, physical activity, height, weight, blood pressure, and cholesterol.
Participants were followed for an average of 20 years. A total of 46,341 participants died. Of those, 12,621 deaths were due to cardiovascular disease. Of the cardiovascular deaths, 6,202 were caused by a heart attack.
What did they discover?
- Overall, coffee drinking was not a dangerous habit.
- Unfiltered did not raise the risk of death compared to abstaining from coffee – except in men aged 60 and above, where unfiltered brew was linked with elevated cardiovascular mortality
- Drinking filtered was safer than no coffee at all.
- Compared to no coffee, filtered brew was linked with a 15% reduced risk of death from any cause during follow up.
- For death from cardiovascular disease, filtered brew was associated with a 12% decreased risk of death in men and a 20% lowered risk of death in women compared to no coffee.
- The lowest mortality was among consumers of 1 to 4 cups of filtered per day.
- They did note a tendency of a higher mortality at higher consumption levels
- Side Note: the unit of measurement “a cup” is not defined. I’m assuming a standard sized cup as found in a kitchen cupboard and not a huge 32oz behemoth.
Comments from the Researchers
Study Author Professor Dag S. Thelle of the University of Gothenburg, Sweden …
“Our study provides strong and convincing evidence of a link between coffee brewing methods, heart attacks and longevity, Unfiltered coffee contains substances which increase blood cholesterol. Using a filter removes these and makes heart attacks and premature death less likely.”
“We wondered whether this effect on cholesterol would result in more heart attacks and death from heart disease. But it was unethical to do a trial randomising people to drink coffee or not. So we set up a large population study and several decades later we are reporting the results.”
“The finding that those drinking the filtered beverage did a little better than those not drinking coffee at all could not be explained by any other variable such as age, gender, or lifestyle habits. So we think this observation is true.”
“We only had one measurement of coffee consumption, but we know that brewing habits were changing in Norway during the follow-up period. We believe that some women and younger men drinking unfiltered coffee switched to filtered, thereby reducing the strength of the association with cardiovascular mortality, whereas older men were less inclined to change their habits.”
One other final point from the study author
Professor Thelle emphasised that these are observational data, but that if public health authorities asked for his advice it would be:
“For people who know they have high cholesterol levels and want to do something about it, stay away from unfiltered brew, including coffee made with a cafetière. For everyone else, drink your coffee with a clear conscience and go for filtered.”
Turning a Skeptical eye on this
It is a very very complex topic.
People who drink coffee are also people who often tend to smoke and also drink more. When doing a study like this you must account for such variables, and demonstrate that you have done so.
The way you brew might be masked by what else you do. For example, those that load up their beverage with lots of full fat milk and heap in sugar vs those who drink it without any of that. The researchers are openly honest about this …
…some people use milk, cream, or sugar in their coffee, and some have the habit of consuming sweets together with their coffee. These and other potentially dietary habits were not accounted for….
Some people also have preexisting health conditions, for example high blood pressure, and so consuming our favourite bean-based-beverage can be a bad idea in that context.
People also change what they do over the years. Did their subjects all consistently make it exactly the same way for the last 20 years?
I could keep going, but I think you get the idea now. We can have a degree of appropriate confidence in the results because they did strive to account for many variables. However, being totally sure is almost impossible because there are many other variables in play.
What can we really conclude?
What is encouraging here is that the study was quite rigorous and they did strive to account for many variables …
…The final model included the cups/d, brewing method, total cholesterol, triglycerides, systolic blood pressure, body mass index, educational length, physical activity, use of antihypertensives…
There is also honest discussion in the paper regarding why filtered is better than none at all. They included a recognition that they might have fooled themselves. For example the no-coffee people might actually have a health condition that motivates them to avoid it. That then resulted in an earlier death …
…The lower mortality associated with filtered coffee as compared with no coffee might arise from coffee being rich in antioxidants, including polyphenols. Polyphenols can inhibit oxidation of LDL, exert anti-thrombotic effects, and improve endothelial dysfunction. The evidence for this is from in vitro studies or animal studies.29 Coffee consumption is also associated with lower risk of diabetes, which is a risk factor for CVD.30,31 A selection to the no coffee group is another possibility. People may abstain from coffee due to some conditions apart from those we have accounted for…
It is an interesting result , but be aware that there are also many many other factors in play here. Filtered Coffee is not medicine so don’t start consuming it with a belief that it will improve your health. Instead, look at it this way – if you happen to consume it because you like it, and you have no underlying health condition that merits avoiding it, then what this study reveals is that you are most probably not doing yourself any long term harm as long as you are not consuming too much.
OK, I’m done. I’m off for a coffee now (skimmed milk and no sugar).
Coffee Study: Further Reading
- Paper in European Society of Cardiology (ESC) (23-Apr 2020): Coffee consumption and mortality from cardiovascular diseases and total mortality: Does the brewing method matter?
- Press Release: How to make the healthiest coffee during COVID-19 lockdown