“Coffee is bad” is an old piece of health advice. To my ear, it has the tone of a sermon that has echoed through the centuries. (A xenophobic sermon.) The modern evidence is that coffee is really not that bad. So why does the myth persist?
A confession first: I do love coffee. (Slight conflict of interest.)
I love coffee, but I also love truth. And I dislike dogma, including the “Naturopathic folklore” that has historically informed much of our natural medicine practice. Natural medicine, and nutrition in particular, is steeped in folklore: Avoid fat. Avoid red meat. Avoid eggs. Much of the advice is unproven. Yet, all of it is laden with weighty – almost religious – emphasis. Sinners beware. Eat at the peril of your soul.
Michael Pollan, the author of the brilliant book In Defense of Food, made the following observation:
“Nutrition science is where surgery was in about 1650, you know, really interesting and promising, but would you want to have them operate on you yet? I don’t think so.”
After 15 years of clinical practice, I agree that some of the traditional dietary advice is starting to ring hollow. How can I preach to patients about the perils of coffee if the evidence says something quite different?
The modern evidence says that coffee provides some health benefits, including prevention of liver cancer, breast cancer, Parkinson’s disease and stroke. Why do we fear it?
As a culture, we have a long history of fearing coffee. When coffee was first introduced to Italy in the 17th century, it was viewed with suspicion. It was seen as a foreign, Muslim drink. Furthermore, it was associated with political dissent and the infamous coffee houses. I contend that the historical “bad name” of coffee is deeply steeped in our cultural psyche, and is the reason why coffee is still viewed as bad.
I want my modern Naturopathic practice to break free from a medieval fear of foreigners. I want to offer my patients advice that is founded on something. So what is the evidence for the long-term health effects of moderate coffee consumption?
Health Benefits of Coffee:
- Reduced risk of depression, Alzheimer’s (1), dementia, and Parkinson’s disease (2)
- Improved cognition and memory (3)
- Reduced risk of liver disease (4) gallstones (5) and gout (6)
- Reduced risk of diabetes and improved insulin sensitivity (7)
- Some evidence for a reduced risk of cancers including liver and breast cancer. (8)
Coffee beans have a complex biochemistry, and contain more than just caffeine. Some of the health benefits may be attributable to polyphenols and other compounds. That said, caffeine itself is the active ingredient that improves insulin sensitivity.
Health Risks of Coffee:
- Stomach ulcer and acid reflux
- Anxiety and sleep disturbance
- Iron deficiency (prevents absorption)
- Miscarriage and reduced female fertility
- Blood pressure was previously believed to be a risk, but recent evidence discounts that. A recent Harvard study found ‘no convincing link’ between ‘paper-filtered coffee’ and heart disease (9).
The Big Picture of Coffee
The jury is still out, but the balance of evidence so far is that coffee offers some surprising health benefits.
In the big picture, coffee is not the worst thing in your diet. Far, far worse, is the sugar in your hot chocolate. And the cake!
Some Cautions About Coffee
Coffee is heavily sprayed with pesticides, so if you’re going to drink coffee, then choose organic. Furthermore, the healthiest method of preparation is paper-filter, which removes the coffee toxins cafestol and kahweol.
Coffee is a drug. It alters mood, and it is addictive. For this reason alone, many people may prefer to avoid it, and that is a choice that I can respect. For those of us consenting adults who are OK with some mild mood altering, then coffee is a relatively healthy option – in moderation. Children are another matter. I recommend that children and teenagers do not regularly consume coffee. The effect of caffeine on a young, developing brain is not known.
Some people do not deal with caffeine very well. Although some of us clear caffeine fairly rapidly (8 to 12 hours), slow metabolizers of caffeine can take up to 24 hours to clear it. If slow metabolizers consume caffeine again within those 24 hours, they will accumulate higher and higher levels over time, and feel terrible. They are the ones at risk for long-term health damage from caffeine. This difference between fast and slow metabolizers could account for the conflicting research findings about coffee. (ie. Bad for some. Good for others.)
Who Is a Slow Caffeine Metabolizer?
- Genetics. Some people are just born with a slow caffeine clearance.
- Pregnancy slows caffeine clearance. Pregnant women should not consume coffee.
- Certain medications slow caffeine clearance. These include HRT and the Pill. So women on the Pill should not consume caffeine. Or, more sensibly, women who drink coffee should not take the Pill.
This is a blog on hormone health, so I will end with a discussion of coffee’s effects on hormonal health.
- Coffee improves insulin sensitivity. In this regard, coffee is beneficial for diabetes and PCOS.
- Coffee assists with estrogen clearance. This can be good or bad. It decreases the body’s total exposure to estrogens, which is how it protects against breast cancer. It may also be why coffee decreases female fertility.
- Coffee increases the release of cortisol and adrenalin from the adrenal glands. In large amounts, and over a long-term, this may disrupt sleep and impair the body’s ability to deal with stress.
Yours in Health,
- Lindsay, J., et al., Risk Factors for Alzheimer’s Disease: A Prospective Analysis from the Canadian Study of Health and Aging, Am J Epidemiol 2002; 156:445-453
- Benedetti M.D. et al., Smoking, alcohol, and coffee consumption preceding Parkinson’s disease, Neurology, 2000:55, 1350-1358
- Johnson-Kozlow, M., et al. Coffee Consumption and Cognitive Function among Older Adults. Am J Epidemiol 2002; 156:842–850
- Klatsky AL et al. Coffee, cirrhosis, and transaminase enzymes. 2006 Arch. Intern. Med. 166 (11): 1190-5.
- Leitzmann MF et al. Coffee intake is associated with lower risk of symptomatic gallstone disease in women, Gastroenterology, 2002 Dec;123(6):1823-30
- Choi, HK et al. Coffee consumption and risk of incident gout in men: A prospective study. 2007 Arthritis Rheum 56 (6): 2049-55. doi:10.1002/art.22712
- Huxley R et al. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus. 2009 Arch Intern Med 169 (22): 2053-2063.
- Ganmaa D, et al.. Coffee, tea, caffeine and risk of breast cancer: a 22-year follow-up. 2008 Int. J. Cancer 122 (9): 2071-6. doi:10.1002/ijc.23336. PMID 18183588
- Lopez-Garcia E et al. Coffee consumption and coronary heart disease in men and women: a prospective cohort study. Circulation 2006;113:2045-53. PMID 16636169.