In this first Summer Series, we’d like to demystify some of the latest, scientific findings on coffee! And hopefully do our part to clarify and counteract all the misinformation that’s so easily found in our online feeds these days! Below, an amazing scientific review by our own medical expert - Jolian Rios, MD, ABIM Board Certified.
Myth #1: All Studies are Scientifically Valid
Coffee has been widely studied - there have been hundreds of studies published about it over the years. Yet, the first thing to keep in mind is that not all studies are created equal - as they can go from very strict, scientifically valid Cohort, Case-Control, and Randomized Controlled Trials where data drives the findings, to an Opinion Paper, which is simply someone sharing their thoughts - of course, their findings do not carry the same weight! To make matters worse, these Opinion Papers are many times “interpreted” and reported by the media in ways that favor their ratings. So every time you read something, go to the source, and please don’t share it if it is not a scientific source! - advice that seems especially relevant right now!
Myth #2: Coffee = Caffeine
When we think of coffee, we immediately think about caffeine; yet we should keep in mind coffee contains many other compounds with potential health benefits. These include polyphenols such as caffeic acid, chlorogenic acid, diterpenoids, and other antioxidants, as well as potassium, magnesium, niacin, and lignans. In fact, concentrations of these phenolic antioxidants are much higher in brewed coffee than in brewed tea - which is often touted as an antioxidant powerhouse!
Myth #3: Caffeine is Unhealthy
Caffeine is quickly absorbed in the gastrointestinal tract, and it gets metabolized by the liver. It antagonizes adenosine receptors in the central and peripheral nervous systems - and in this way, it can have a variety of effects. Some of the main effects found so far:
Caffeine is a proven analgesic, property that has been used for the treatment of headaches, specifically tension and migraine headaches [1,2].
Multiple cohort studies with over 600,000 individuals found it may reduce stroke risk [3-6].
Two case-controlled studies and two cohort studies have shown a small protective effect of coffee consumption advanced Alzheimer’s disease. Moreover, animal models have shown long-term caffeine consumption may delay or reduce the risk of Alzheimer's disease [7,8].
Randomized Controlled Trials of healthy individuals have found caffeine improves cognition, mood, vigilance, and reaction time - regardless of age and gender [9-14].
A study with sleep-deprived Navy SEAL trainees showed improvement of cognitive function, learning, memory, and mood despite continuous exposure to stressors with an optimal dose of 200 mg of caffeine (about two cups of coffee!) [15].
Myth #4: Coffee is Unhealthy
Numerous studies on coffee have actually shown the opposite - there are several health benefits from long-term coffee consumption. Some examples:
A matched case-control of almost 1700 women with BRCA gene mutation found that coffee intake was associated with 10% - 69% lower risk of breast cancer, this was a dose-dependent effect, with the lowest effect being seen on women who drank 1-3 cups of coffee and the largest effect seen on those who drank more than 6 cups of coffee per day [16]
A case-control study of 1900 women found that coffee intake was associated with a 40% lower risk of breast cancer in premenopausal women who drank 4 or more cups of coffee per day [17].
A meta-analysis of cohort and case-control studies showed a decreased risk of endometrial cancer in coffee drinkers [18].
A large prospective analysis of over 47,000 men found a strong dose-dependent reduction in the risk of prostate cancer [19].
Several studies, including randomized trials, and cohort studies, have shown that coffee consumption, including decaf, decreases the risk of type 2 diabetes, by improving insulin sensitivity as well as insulin secretion [20-24].
Another study showed caffeine in coffee to be a potent stimulator of smooth muscles that prevent constipation [25].
A meta-analysis of 14 different studies shows that coffee drinkers had 39% less probability of developing cirrhosis [26].
Thus, coffee has been shown to have positive effects on multiple systems and may even lower the risk of multiple chronic diseases in the long term. I’ve listed the studies used for reference, in case you’d like to read in a lot more detail on your own (it pairs perfectly with a great cup of Ethos to keep you awake!).
So, let’s keep enjoying coffee, and let’s continue to make a difference, to Brew Greatness in the world!
- Jolian
REFERENCES
Goldstein J, Silberstein SD, Saper JR, Ryan RE Jr, Lipton RB. Acetaminophen, aspirin, and caffeine in combination versus ibuprofen for acute migraine: results from a multicenter, double-blind, randomized, parallel-group, single-dose, placebo-controlled study. Headache. 2006;46(3):444-453. doi:10.1111/j.1526-4610.2006.00376
Diener HC, Gold M, Hagen M. Use of a fixed combination of acetylsalicylic acid, acetaminophen and caffeine compared with acetaminophen alone in episodic tension-type headache: meta-analysis of four randomized, double-blind, placebo-controlled, crossover studies. J Headache Pain. 2014;15(1):76. Published 2014 Nov 19. doi:10.1186/1129-2377-15-76
Larsson SC, Virtamo J, Wolk A. Coffee consumption and risk of stroke in women. Stroke. 2011;42(4):908-912. doi:10.1161/STROKEAHA.110.603787
Lopez-Garcia E, Rodriguez-Artalejo F, Rexrode KM, Logroscino G, Hu FB, van Dam RM. Coffee consumption and risk of stroke in women. Circulation. 2009;119(8):1116-1123. doi:10.1161/CIRCULATIONAHA.108.826164
Larsson SC, Männistö S, Virtanen MJ, Kontto J, Albanes D, Virtamo J. Coffee and tea consumption and risk of stroke subtypes in male smokers. Stroke. 2008;39(6):1681-1687. doi:10.1161/STROKEAHA.107.504183
Larsson SC, Orsini N. Coffee consumption and risk of stroke: a dose-response meta-analysis of prospective studies. Am J Epidemiol. 2011;174(9):993-1001. doi:10.1093/aje/kwr226
Arendash GW, Schleif W, Rezai-Zadeh K, et al. Caffeine protects Alzheimer's mice against cognitive impairment and reduces brain beta-amyloid production. Neuroscience. 2006;142(4):941-952. doi:10.1016/j.neuroscience.2006.07.021
Barranco Quintana JL, Allam MF, Serrano Del Castillo A, Fernández-Crehuet Navajas R. Alzheimer's disease and coffee: a quantitative review. Neurol Res. 2007;29(1):91-95. doi:10.1179/174313206X152546
Fredholm BB, Bättig K, Holmén J, Nehlig A, Zvartau EE. Actions of caffeine in the brain with special reference to factors that contribute to its widespread use. Pharmacol Rev. 1999;51(1):83-133.
Jarvis MJ. Does caffeine intake enhance absolute levels of cognitive performance?. Psychopharmacology (Berl). 1993;110(1-2):45-52. doi:10.1007/BF02246949
Kamimori GH, Johnson D, Thorne D, Belenky G. Multiple caffeine doses maintain vigilance during early morning operations. Aviat Space Environ Med. 2005;76(11):1046-1050.
Lorist MM, Snel J, Kok A, Mulder G. Influence of caffeine on selective attention in well-rested and fatigued subjects. Psychophysiology. 1994;31(6):525-534. doi:10.1111/j.1469-8986.1994.tb02345.x
Ker K, Edwards PJ, Felix LM, Blackhall K, Roberts I. Caffeine for the prevention of injuries and errors in shift workers. Cochrane Database Syst Rev. 2010;2010(5):CD008508. Published 2010 May 12. doi:10.1002/14651858.CD008508
Smith A, Sutherland D, Christopher G. Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers. J Psychopharmacol. 2005;19(6):620-626. doi:10.1177/0269881105056534
Lieberman HR, Tharion WJ, Shukitt-Hale B, Speckman KL, Tulley R. Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land. Psychopharmacology (Berl). 2002;164(3):250-261. doi:10.1007/s00213-002-1217-9
Nkondjock A, Ghadirian P, Kotsopoulos J, et al. Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers. Int J Cancer. 2006;118(1):103-107. doi:10.1002/ijc.21296
Baker JA, Beehler GP, Sawant AC, Jayaprakash V, McCann SE, Moysich KB. Consumption of coffee, but not black tea, is associated with decreased risk of premenopausal breast cancer. J Nutr. 2006;136(1):166-171. doi:10.1093/jn/136.1.166
Bravi F, Scotti L, Bosetti C, et al. Coffee drinking and endometrial cancer risk: a metaanalysis of observational studies. Am J Obstet Gynecol. 2009;200(2):130-135. doi:10.1016/j.ajog.2008.10.032
Wilson KM, Kasperzyk JL, Rider JR, et al. Coffee consumption and prostate cancer risk and progression in the Health Professionals Follow-up Study. J Natl Cancer Inst. 2011;103(11):876-884. doi:10.1093/jnci/djr15
Huxley R, Lee CM, Barzi F, et al. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. Arch Intern Med. 2009;169(22):2053-2063. doi:10.1001/archinternmed.2009.439
van Dam RM, Feskens EJ. Coffee consumption and risk of type 2 diabetes mellitus. Lancet. 2002;360(9344):1477-1478. doi:10.1016/S0140-6736(02)11436-X
Rosengren A, Dotevall A, Wilhelmsen L, Thelle D, Johansson S. Coffee and incidence of diabetes in Swedish women: a prospective 18-year follow-up study. J Intern Med. 2004;255(1):89-95. doi:10.1046/j.1365-2796.2003.01260.x
van Dam RM, Willett WC, Manson JE, Hu FB. Coffee, caffeine, and risk of type 2 diabetes: a prospective cohort study in younger and middle-aged U.S. women. Diabetes Care. 2006;29(2):398-403. doi:10.2337/diacare.29.02.06.dc05-1512
Salazar-Martinez E, Willett WC, Ascherio A, et al. Coffee consumption and risk for type 2 diabetes mellitus. Ann Intern Med. 2004;140(1):1-8. doi:10.7326/0003-4819-140-1-200401060-00005
Murakami K, Okubo H, Sasaki S. Dietary intake in relation to self-reported constipation among Japanese women aged 18-20 years. Eur J Clin Nutr. 2006;60(5):650-657. doi:10.1038/sj.ejcn.1602365
Liu F, Wang X, Wu G, et al. Coffee Consumption Decreases Risks for Hepatic Fibrosis and Cirrhosis: A Meta-Analysis. PLoS One. 2015;10(11):e0142457. Published 2015 Nov 10. doi:10.1371/journal.pone.0142457
