Coffee is well known as a performance-enhancing substance, but did you know that it also reliably associates with positive health outcomes? Read on and discover more reasons to enjoy this delicious beverage.
Coffee is one of the most commonly consumed beverages in the world, and for good reason. Caffeine—one of the main active ingredients in coffee—is a recognised performance-enhancing substance, for both physical and cognitive (mental) performance (1). However, that is not what we’re going to chat about today. Here, we’ll talk about the health effects of coffee consumption with reference to chronic disease risk.
Too Good to be True?
I know, it seems too good to be true that coffee may be considered a health food. But, when it comes to evaluating the health effects of a food, we refer to the evidence and not our intuitions. In doing so, it is apparent that coffee consumption is associated with reduced risk of various chronic diseases. In this article, we will discuss the contents of an umbrella review published in the British Medical Journal in 2017, which included a number of meta-analyses (studies combining the results of multiple other studies) looking at the association between coffee consumption and a number of health outcomes (2).
Associations with Positive Health Outcomes
Death from any Cause
In the most recent meta-analysis included in this umbrella review, researchers looked at the association between coffee consumption and risk of death (from any cause) from a combined 24 cohort studies (3). Results showed that when consuming any amount of coffee, the risk of death was reduced versus consuming none. The largest reduction in risk (17%) was observed at an intake of 3 *cups per day (Figure 1). Beyond this level of intake, the reduction in risk was less pronounced.
*A cup was defined as 150 ml.
Cardiovascular Death
In the same analysis, a similar association was observed between coffee consumption and cardiovascular death, where any amount of consumption fared better than none. This time, a 19% reduced risk was reported for an intake of 3 cups per day versus no consumption (Figure 1) (3). A 30% reduction in stroke risk was also observed at this level of intake, although this finding was from a smaller number of studies (9 as opposed to 23 for cardiovascular death). As coffee consumption increased beyond 3 cups per day (to a maximum of 7 cups per day), the associations became weaker—just like the associations between coffee intake and death from any cause, as discussed previously.
Figure 1. The association between coffee consumption (in cups per day) and death from any cause (all cause mortality), and death from cardiovascular disease (CVD mortality). The red lines show that maximal risk reductions were observed for a consumption of ~3 cups per day (3).
Cancer Death
In a meta-analysis of 40 cohorts including over 2.2 million individuals, regular coffee drinkers experienced a 13% reduced risk of cancer compared to those who did not or seldom drink coffee (4). Similar associations were revealed for most types of cancer, where coffee was associated with a reduced risk of bladder, breast, mouth/throat, colorectal, endometrial, oesophageal, liver, leukemic, pancreatic, and prostate cancers. However, coffee was not significantly associated with stomach, lung, non-melanoma, ovarian, or kidney cancer in this meta-analysis.
In the meta-analysis discussed earlier, the risk of cancer death was reduced only in people who didn’t smoke, and decreased in a linear fashion as coffee consumption increased (up to 7 cups per day) (3). For smokers on the other hand, the opposite was observed.
Type 2 Diabetes
In another meta-analysis including 28 studies and approximately 1.1 million individuals, the risk of type 2 diabetes was reduced in a linear fashion by 9% in those drinking 1 cup per day, by 20% in those drinking 3.5 cups per day, and by 30% in those drinking 5 cups per day, all compared to those not consuming coffee (5). Consumption of decaffeinated coffee showed similar associations.
Other Outcomes
There is further evidence of associations between higher coffee consumption and lower risk of other health conditions, including chronic liver disease, Parkinson’s disease, and Alzheimer's disease, in other meta-analyses (2).
Why Might Coffee be Healthy?
Coffee is the vehicle in which approximately 1,000 bioactive components enter the body. These include caffeine, chlorogenic acids, and diterpenes, and there are data suggesting independent positive health effects from each substance relating to their anti-inflammatory and antioxidant activity (3). It is important to be clear on one thing, though: in this article, we are strictly discussing the healthfulness of coffee, not the milk, sugar, whipped cream, or otherwise that often make their way into a coffee beverage.
Evidence for Negative Health Effects of Consuming Coffee
Despite the literature being overwhelmingly positive in relation to coffee and health outcomes, there are some data suggesting negative effects for certain outcomes. Coffee consumption was associated with an increased risk for lung cancer in one meta-analysis, however this association was only observed in smokers (2). In women only, coffee consumption was associated with increased risk of fractures, increasing by 2% for those consuming 2 cups per day, to 54% for those consuming 8 cups per day (all relative to non-consumers) (6). Coffee consumption has also been associated with a number of adverse pregnancy-related outcomes (2). The rationale for these associations is not yet fully understood.
Summary
When it comes to health, coffee seems to be an overwhelmingly positive food for reducing the risk of a number of chronic conditions. For full disclosure, this article was written with a heavy dose of coffee in my system!
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Until next week!
Patrick Elliott, BSc, MPH
Health and Nutrition Science Communication Officer at Training121
Founder of Just Health — IG: @just.health.info
Health Disclaimer: this article is for informational and educational purposes only, and is not a substitute for professional advice. For health advice, speak to a physician or other qualified health-care professional, and for nutrition advice, speak to a qualified nutrition professional (e.g., registered dietitian). The use of information on this app/site is solely at your own risk.
References
(1) Guest NS, VanDusseldorp TA, Nelson MT, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1. Available at: https://pubmed.ncbi.nlm.nih.gov/33388079/
(2) Poole R, Kennedy OJ, Roderick P, Fallowfield JA, Hayes PC, Parkes J. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ. 2018 Jan 12;360:k194. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5696634/
(3) Grosso G, Micek A, Godos J, et al. Coffee consumption and risk of all-cause, cardiovascular, and cancer mortality in smokers and non-smokers: a dose-response meta-analysis. Eur J Epidemiol. 2016;31(12):1191-205. Available at: https://link.springer.com/content/pdf/10.1007/s10654-016-0202-2.pdf
(4) Yu X, Bao Z, Zou J, Dong J. Coffee consumption and risk of cancers: a meta-analysis of cohort studies. BMC Cancer. 2011;11:96. Available at: https://pubmed.ncbi.nlm.nih.gov/21406107/
(5) Ding M, Bhupathiraju SN, Chen M, van Dam RM, Hu FB. Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response meta-analysis. Diabetes Care. 2014;37(2):569-586. Available at: https://pubmed.ncbi.nlm.nih.gov/24459154/
(6) Lee DR, Lee J, Rota M, et al. Coffee consumption and risk of fractures: a systematic review and dose-response meta-analysis. Bone. 2014;63:20-28. Available at: https://www.sciencedirect.com/science/article/pii/S8756328214000441
Technical Terms
Caffeine: A substance found in coffee that is a central nervous system stimulant, meaning that it improves attention and cognitive performance, and also improves a range of exercise performance outcomes.
Meta-analysis: A type of study that combines the results of a number of other studies that look at the same thing, and produces a summative estimate of the effect or association between exposure and outcome. For example, a meta-analysis of five studies looking at smoking (exposure) and lung cancer (outcome) would combine the results from all five studies into one overall result, with the intention of providing a better estimate of the true effect of smoking on lung cancer.
Umbrella review: A type of review that systematically searches, organises, and evaluates existing evidence from multiple systematic reviews and/or meta-analyses on all health outcomes associated with a particular exposure. In this article, we discuss an umbrella review that organised and evaluated evidence from meta-analyses assessing the association between coffee consumption and a wide range of health outcomes.
Chlorogenic acids: Substances found in coffee that may induce positive health effects.
Diterpenes: Substances found in coffee that may induce positive health effects. Interestingly, they may slightly elevate cholesterol levels. Instant and filtered coffee contain much less diterpenes than unfiltered coffee, and can be enjoyed without the worry of increased cholesterol levels.