Coffee & Health: What it actually does.
First things first, I need to declare my bias: I love coffee. Now, onto the science.
Coffee can provide a very significant portion of the daily intake of antioxidants for humans. Antioxidants do what they say on the tin, they scavenge oxygen. Oxidation occurs naturally in our bodies as part of the ageing process. An antioxidant rich diet can help to marginally slow this process.
Coffee increases the feeling of alertness as it contains caffeine which blocks adenosine in the brain. Adenosine simply makes us feel tired. Feeling less tired means we might be more motivated or productive. A study done on women showed that drinking 1–2 cups of coffee or >1 cup of tea per day was associated with 17% and 13–26% increased likelihood of meeting physical activity guidelines.
Caffeine can also alter our perception of exertion level or fatigue. This can be helpful when exercising as it means we may get more reps, or do more work at a higher intensity. A study in weight lifters found that caffeine supplementation reduced reported RPE during exercise.
Caffeine accelerates the release of exercise-induced beta-endorphin. This type of endorphin is a stress reducer and is responsible for the post workout high so combining caffeine with activity seems like an increasingly good idea.
Meta-analyses have suggested that coffee consumption versus no coffee consumption is associated with an up to 17% risk reduction of all-cause mortality. There are loads of studies on this.
It’s also very well researched that habitual coffee consumption is associated with a substantially lower risk of type 2 diabetes.
I also found multiple (quality) studies supporting coffee consumption for liver health. Specifically it seems to improve outcomes for patients with chronic liver disease, non-alcoholic fatty liver disease and cirrhosis.
What Coffee Doesn’t Do:
It doesn’t ‘burn out’ or ‘crash’ your adrenal glands as adrenal fatigue is a fabricated term that’s not medically recognised or supported by any good evidence.
It doesn’t dehydrate you or leach the minerals from your bones. It actually counts towards hydration.
It doesn’t increase your blood pressure. This has been thoroughly de-bunked.
It doesn’t contain loads of carcinogenic acrylamide. Studies show there is more in potato chips and wine. Estimated levels of dietary exposure to acrylamide are not pose a neurotoxic threat at the moment.
Worth noting: over consumption of anything can have potential for negative side effects, coffee and caffeine are no exception to this. Consume responsibly.
References: Antioxidant content of coffee: https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-9-3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4665516/
Coffee increases women meeting PA guidelines: http://www.mdpi.com/1660-4601/15/9/1812/htm
RPE study: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0838.2005.00445.x
Caffeine & performance: https://www.ncbi.nlm.nih.gov/pubmed/20205813
1. Malerba S. et al. (2013) A meta-analysis of prospective studies of coffee consumption and mortality for all causes, cancers and cardiovascular diseases. Eur J Epidemiol, 28(7):527-39. 1. Je Y., Giovannucci E. (2014) Coffee consumption and total mortality: a meta-analysis of twenty prospective cohort studies. Br J Nutr, 111(7):1162-73. 2. Crippa A. et al. (2014) Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: a dose-response meta-analysis. Am J Epidemiol, 180(8):763-75. 2. Zhao Y. et al. (2015) Association of coffee drinking with all-cause mortality: a systematic review and meta-analysis. Public Health Nutr, 18(7):1282-91. 3. Grosso G. et al. (2016) Coffee consumption and mortality in three Eastern European countries: results from the HAPIEE (Health, Alcohol and Psychosocial factors In Eastern Europe) study. Eur J Epidemiol, 31(12):1191-1205. 4. Poole R. et al. (2017) Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ, 359:j5024. 5. Gunter, M.J. et al (2017) Coffee drinking and mortality in 10 European countries. Ann Int Med, 167(4):236-24. 6. Song-Yi Park et al. Association of Coffee Consumption With Total and Cause-Specific Mortality Among Nonwhite Populations. Ann Int Med, 10.7326/M16-2472
Diabetes: https://jamanetwork.com/journals/jama/article-abstract/201177 https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/773949 http://care.diabetesjournals.org/content/37/2/569.short https://academic.oup.com/nutritionreviews/article-abstract/76/6/395/4954186
Liver health: https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0038-1666869 https://onlinelibrary.wiley.com/doi/abs/10.1111/apt.13523 https://onlinelibrary.wiley.com/doi/abs/10.1111/liv.12304
Adrenal Fatigue: https://hormonesdemystified.com/adrenal-fatigue-a-fraud-perpetrated-on-unsuspecting-patients Dehydration: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0084154 https://www.ncbi.nlm.nih.gov/pubmed/20205813
Blood Pressure: https://journals.lww.com/jhypertension/Abstract/2012/12000/The_effect_of_coffee_consumption_on_blood_pressure.1.aspx https://academic.oup.com/ajcn/article/94/4/1113/4598121 https://academic.oup.com/ajcn/article/93/6/1212/4597708 Acrylamide: https://www.tandfonline.com/doi/abs/10.1080/19440049.2018.1508893