A recent study indicates that drinking coffee is associated with several health and longevity benefits. The study included 450,000 people, investigating how coffee drinking was linked with the risk of developing:
- Arrhythmia (irregular heartbeats).
- Cardiovascular disease (diseases of the heart and blood vessels).
- Dying during the 12.5 years they were tracked.
Surprisingly, the researchers found that drinking ground or instant coffee was linked to a lower risk of arrhythmia. All types of coffee were linked to a lower risk of cardiovascular disease. Drinking coffee was also linked to a lower risk of dying.
Overall, the study suggests that drinking coffee may be associated with a lower risk of certain health problems and a longer lifespan. However, the research has some limitations.
While the sample size is enormous, the data are observational. This means that the researchers observed and recorded actions and characteristics without manipulating or interfering with their natural environment or behaviour.
Limitations in observational research
While observational research can generate important insights, it is often difficult to determine cause and effect. For example, if a study observes that people who eat a lot of vegetables have a lower risk of heart disease, it does not necessarily mean that the vegetables are the cause of the lower risk. Other factors, such as a healthier lifestyle, could contribute to the lower risk.
Researchers often use a hazard ratio to help control for these other factors, as in the coffee study I shared. This is a way to compare the risk of a particular outcome (such as cardiovascular disease) between two groups (those who drink a lot of coffee and those who don’t). However, even with a hazard ratio, it is still possible that other factors are not being considered, so the study results should be interpreted with caution.
Potential mechanisms which explain the positive effects
Despite these limitations, several studies have attempted to identify the causal mechanisms by which coffee consumption may positively affect health. Some potential mechanisms include:
- Antioxidant effects: Coffee contains many compounds with antioxidant properties, which means they can neutralise harmful substances called free radicals that can damage cells and contribute to developing certain diseases.
- Anti-inflammatory effects: Some studies have suggested that coffee consumption may have anti-inflammatory effects, which could help to reduce the risk of certain chronic diseases.
- Cardiovascular health: Some research has found that coffee consumption may be associated with a lower risk of cardiovascular disease. One potential mechanism for this effect could be that coffee consumption increases HDL (good) cholesterol levels and decreases LDL (bad) cholesterol levels.
- Diabetes prevention: Some studies have suggested that coffee consumption may be associated with a reduced risk of type 2 diabetes. One potential mechanism for this effect is that coffee consumption may improve insulin sensitivity and reduce the risk of developing insulin resistance, which is a critical factor in developing type 2 diabetes.
It is important to note that the mechanisms by which coffee consumption may positively affect health still need to be fully understood. More research is required to confirm these studies’ findings, but the results are promising.
Overall, the largest risk reduction for various health outcomes seems to be associated with three to four cups daily and more likely to benefit health than harm.
Chieng D, Canovas R, Segan L, Sugumar H, Voskoboinik A, Prabhu S, Ling LH, Lee G, Morton JB, Kaye DM, Kalman JM, Kistler PM. The impact of coffee subtypes on incident cardiovascular disease, arrhythmias, and mortality: long-term outcomes from the UK Biobank. Eur J Prev Cardiol. 2022 Dec 7;29(17):2240-2249. doi: 10.1093/eurjpc/zwac189. PMID: 36162818.
Poole, R., Kennedy, O. J., Roderick, P., Fallowfield, J. A., Hayes, P. C., & Parkes, J. (2017). Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ (Clinical Research Ed.), 359, j5024. https://doi.org/10.1136/bmj.j5024