I keep reading about the health effects of coffee, yet I have been taught all my life to stay away from this beverage. Seems there are articles and opinions on both sides. It gives me confidence to know that there are actually loads of science about coffee’s health benefits and potential adverse effects…so I’d like to share with you what I’ve learned about coffee and caffeine — including that you can safely enjoy this natural drink.
A word of caution when reading about coffee’s effects
Let’s face it, advertising and hype is everywhere. You have to be smart and look at the data behind claims. As I followed further into claims about coffee’s potential adverse health effects, I met with some familiar pitfalls by naysayers. They generalize their claims about coffee, but later refer to heavy coffee consumption or to heavy caffeine consumption from any source.
For example, the claim [1] that coffee lowers men’s sperm counts by 30% turned out to be deceptive and actually not even true. Quoting researchers at a Copenhagen, Denmark University on a study of high caffeine consumption and its effects on sperm count, it was the 800 mg of daily caffeine consumed in the form of mainly Cola that caused the lower sperm count, while the men who primarily consumed coffee and tea had no change in their sperm count.
Moreover, the same article made the claim that coffee reduces a woman’s chances of getting pregnant by 27%. However, if you read the entire article you find that the study was done on mice that were given high amounts of caffeine, which appeared to slow fallopian tube muscular contraction, resulting in the observed decreased fertility effect. They did not study women who drank coffee. Remember that coffee is much more than just caffeine—and more than 30 years of research has revealed coffee’s many antioxidants and cell-protective compounds.
Finally, when reading about adverse claims, differentiate between heavy (more than 4 cups per day everyday) versus moderate (1-3 cups or less per day). There really is a big difference here. Also know that heavy coffee drinkers are more likely smoke, eat junk food routinely, have high uncontrolled stress, and lack consistent exercise—and study data must control for these factors but usually do not.
The adverse claims about coffee
Here are the predominant adverse effects of coffee consumption:
- Slows iron or other mineral absorption: Coffee inhibits iron absorption from meat by 39%, but no decreased iron absorption is found when coffee is consumed one hour before a meal. [2] I suggest you simply don’t drink coffee with your meal. Also, recognize that other foods block iron and mineral absorption too—food such as grains, certain seeds, nuts and beans (high in phytic acid); spinach and other leafy greens (high in oxalates); berries and apples (high in polyphenols); eggs (contain phosuitin); and dairy such as milk, yogurt and cheese (high in calcium). The claim that coffee promotes the urinary loss of calcium, zinc, magnesium and other important minerals relates to the diuretic effect (increase urination) that can occur in heavy coffee consumption.
- Bone density loss: Unfortunately, it has been shown in one study (but not in four other meta-analyses, except in elderly women) that high coffee consumption showed a slight worsening of bone density, but no significantly worsened facture rates.
- Acrylamide in coffee: it is known that acrylamide is a potentially carcinogenic (cancer-causing) substance and that it can be produced when foods (including coffee beans) are roasted at a high temperature, [3] as it is occurs when browning toast and crispy French fries. When laboratory mice were fed huge doses throughout their lives, acrylamide caused tumors. However, the amounts of acrylamide in foods are thousands of times lower for humans. Forty studies have shown little to no risk of cancer in humans. Plus, it is essentially nonexistent in brewed coffee and only a fraction is found in roast and ground coffee beans.
- Ages your skin: A study [4] in 2014 showed that caffeine (not coffee) slowed an enzyme responsible for collagen biosynthesis in cultured skin cells—but this certainly does not prove coffee accelerates skin aging because it contains antioxidants and cell-protective compounds; caffeine does not.
- Gout flare-up: A study showed those who binge on caffeinated drinks (not specific to coffee) increase their risk for a gouty arthritis pain.
- Urinary incontinence: Women who consume high amounts of caffeine (more than 329 mg daily) are more likely to experience A cup of coffee contains from 65-275 mg of caffeine depending on the coffee blend, amount of ground coffee, and brewing technique. If incontinence occurs, stop drinking it.
- Other symptoms: Coffee consumption has been known to worsen anxiety, insomnia, indigestion/heartburn, headaches, allergies, and menopausal symptoms. If any of these symptoms occur, stop drinking coffee.
How coffee promotes health
Rest assured, the health benefits of coffee dwarf its few and easily avoidable adverse effects, especially when four or less cups per day are consumed. Beyond drinking coffee for its taste and feel good effects, it has additionally been shown in plenty of scientific studies to:
- Delay and/or prevent Alzheimer’s dementia and Parkinson’s disease due to its improvement of cognitive function (alertness, concentration, learning, memory and mood). < [5]
- Lower heart disease risk (or at least does not increase it [6] [7] [8] at modest consumption); reduces heart failure [9] but there is a trend to worsen heart failure at higher coffee consumption (more than 4 cups per day). [10] There is a protective relationship between caffeinated coffee consumption and the onset of heart valve disease. [11]
- Lower the risk of stroke. [12]
- Lower blood pressure: Green coffee [13] (but not black coffee) consumption.
- Improve type 2 diabetes [14] [15] [16] [17] [18]
- Reduce many cancers: Including skin, [19] colo-rectal, [20] mouth and throat, [21] [22] prostate, [23] liver, [24] [25] endometrial, [26] [27] and breast [28] [29] cancers.
- Liver health: Improves liver function. [30]
- Treat obesity: Green coffee consumption is shown to reduce abdominal fat. [31]
- Reduce tooth loss from periodontal disease. [32]
- Reduce spontaneous DNA strand breaks in the white blood cells of men. [33]
A clear distinction: coffee versus sodas/energy drinks
You know by now that not all caffeinated drinks have similar effects on your health. Sodas and energy drinks contain artificial colorings, flavorings, preservatives, excess refined sugar (or artificial sweeteners), excess phosphorus and a very acidic pH effect.
These “soft” drinks can also be so loaded with stimulants that they are essentially drug uppers. If you search the peer-reviewed literature it will not take long to discover there are no health benefits of caffeinated sodas and energy drinks. Yet their adverse effects are many, including:
- Weight gain
- Diabetes
- Osteoporosis
- Potassium depletion
- Blood vessel problems
- Seizure disorders
- Heart attack and stroke risk
- Tooth decay
- Chronic kidney disease
- Kidney stones
To feeling good for better health,
Michael Cutler, M.D.
Easy Health Options
[1] http://www.caffeineinformer.com/caffeine-for-birth-control
[2] http://ajcn.nutrition.org/content/37/3/416.abstract
[3] http://www.forbes.com/sites/alicegwalton/2013/11/15/the-fda-calls-out-yet-another-food-chemical-to-avoid-acrylamide/
[4] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4206198/
[5] http://coffeeandhealth.org/topic-overview/coffee-and-age-related-cognitive-decline/
[6] Lopez E et al (2011) Coffee consumption and mortality in women with cardiovascular disease. Am J Clin Nutr. 94(1): 218–224.
[7] Zhang WH et al. (2009) Coffee consumption and risk of cardiovascular events and all-cause mortality among women with type 2 diabetes. Diabetologia. 52(5):810-817
[8] Ahmed H et al. (2009) Coffee Consumption and Risk of Heart Failure in Men: an Analysis from the Cohort of Swedish Men. Am Heart J. 158(4):667–672
[9] http://www.livescience.com/50012-coffee-heart-attack-risk.html
[10] Mostofsky E. (2012) Habitual coffee consumption and risk of heart failure: a dose-response meta-analysis. Circ Heart Fail. 5(4): 401-5
[11] Greenberg JA, Chow G, Ziegelstein RC. Caffeinated coffee consumption, cardiovascular disease, and heart valve disease in the elderly (from the Framingham Study) American Journal of Cardiology. 2008;102(11):1502–1508.)
[12] http://www.ncbi.nlm.nih.gov/pubmed/26098738
[13] http://www.ncbi.nlm.nih.gov/pubmed/25133164
[14] van Dam RM et al. (2002) Coffee consumption and risk of type 2 diabetes mellitus. Lancet . 360:1477-8
[15] Huxley R et al. (2009) Coffee, Decaffeinated Coffee, and Tea Consumption in Relation to Incident Type 2 Diabetes Mellitus. Arch Intern Med 169:2053-63
[16] 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 Feb;29(2):398-403
[17] Salazar-Martinez E, Willett WC, et. al. Coffee consumption and risk for type 2 diabetes mellitus. Ann Intern Med 2004 Jan 6;140(1):1-8
[18] Pereira MA, Parker ED, Folsom AR. Coffee consumption and risk of type 2 diabetes mellitus: an 11-year prospective study of 28,812 postmenopausal women. Arch Intern Med. 2006 Jun 26;166(12):1311-6
[19] Fengju Song, Abrar A. Qureshi, Jiali Han. Increased Caffeine Intake Is Associated with Reduced Risk of Basal Cell Carcinoma of the Skin. Cancer Res July 1, 2012; 3282. http://cancerres.aacrjournals.org/content/72/13/3282
[20] Galeone C, Turati F, La Vecchia C, Tavani A. Coffee consumption and risk of colorectal cancer: a meta-analysis of case-control studies. Cancer Causes Control. 2010 Nov;21(11):1949-59
[21] Tavani A, Bertuzzi M, Talamini R, et al. Coffee and tea intake and risk of oral, pharyngeal and esophageal cancer. Oral Oncol. 2003;39(7):695-700.
[22] Rodriguez T, Rodriguez T, Altieri A, et al. Risk factors for oral and pharyngeal cancer in young adults. Oral Oncol. 2004;40(2):207-13.
[23] Wilson KM, Kasperzyk JL, Rider JR. Coffee consumption and prostate cancer risk and progression in the health professionals follow-up study. J Natl Cancer Inst. 2011 Jun 8;103(11):876-84.
[24] Shimazu T, Tsubono Y, Kuriyama S, et al. Coffee consumption and the risk of primary liver cancer: Pooled analysis of two prospective studies in Japan. Int J Cancer. 2005 Aug 10;116(1):150-4.
[25] Bravi F, Bosetti C, Tavani A, et. al. Coffee drinking and hepatocellular carcinoma risk: a meta-analysis. Hepatology. 2007 Aug;46(2):430-5
[26] Bandera EV, et al (2010). Coffee and tea consumption and endometrial cancer risk in a population-based study in New Jersey. Cancer Causes Control;21:1467-73.
[27] McCann SE, et al (2009). Higher regular coffee and tea consumption is associated with reduced endometrial cancer risk. Int J Cancer;124:1650-3.
[28] Li J, Seibold P, Chang-Claude J. Coffee consumption modifies risk of estrogen-receptor negative breast cancer. Breast Cancer Res. 2011 May 14;13(3):R49
[29] Bageman E, Ingvar C, Rose C, Jernstrom H. Coffee consumption and CYP1A2 genotype modify age at breast cancer diagnosis and estrogen receptor status. Cancer Epidemiol Biomarkers Prev. 2008 Apr;17(4):895-901.
[30] Cadden IS, Partovi N, Yoshida EM. Review article: possible beneficial effects of coffee on liver disease and function. Aliment Pharmacol Ther. 2007 Jul 1;26(1):1-8.
[31] http://www.ncbi.nlm.nih.gov/pubmed/25133164
[32] Ng N, Kaye EK, Garcia RI. “Coffee consumption and periodontal disease in males.” J Periodontol. 2014 Aug;85(8):1042-9. http://www.worldhealth.net/news/coffee-combats-tooth-loss/
[33] http://www.nutraingredients-usa.com/Research/Could-coffee-protect-DNA-from-damage/
