Coffee Caveats

Coffee Caveats

Last month in the American Journal of Clinical Nutrition, an editorial entitled “Coffee consumption and risk of chronic diseases: changing our views” reviewed the growing evidence that for most people, the benefits of drinking coffee likely outweigh the risks. For example, a recent analysis of the best studies published to date suggests coffee consumption may lead to a modest reduction in overall cancer incidence, as detailed in my 1-min. video Coffee and Cancer. Each daily cup o’ joe was associated with about a 3% reduced risk of cancers, especially bladder, breast, mouth, colorectal, endometrial, esophageal, liver, leukemic, pancreatic, and prostate cancers.

What about the caffeine, though? Glad you asked! Check out What About the Caffeine?

There are a few caveats. Some health conditions may be worsened by coffee, such as insomnia, anxiety, gastroesophageal reflux (heartburn), high blood pressure, and certain heartbeat rhythm irregularities. There are also compounds in coffee that increase cholesterol levels, but are effectively removed when filtered through paper, so drip coffee is preferable to boiled, French press and espresso. Pregnant women should restrict caffeine consumption to less than two cups of coffee a day.

Despite the growing evidence of health benefits associated with coffee consumption, I still don’t recommend people drink it—not because it’s not healthy, but because there are even healthier choices. In this way, coffee is like a banana, another common convenient plant product. If you have a choice, I’d encourage you to make healthier fruit choices (apples are better, berries are best). Similarly, when it comes to beverages, I’d encourage you to choose an even healthier one, like green tea.

One final note: not all routes of administering coffee are benign. Consider the title of a case reported in a medical journal last month: “Rectal Perforation…Caused by Rectal Burns Associated With Hot Coffee Enemas.”

-Michael Greger, M.D.

Image credit: stevenharris / Flickr

Don't miss out on the latest updates!
Subscribe for free and get the latest in nutrition research delivered straight to your inbox!
  • lowrie

    is there any current information linking caffeine to migraines? off to eat my morning banana… errr… apple!!

    • DrDons

       Headaches(ha) are common. It is important to correctly diagnose the type of headache you have. In my experience many patients who say they have migraines may be suffering from musculo-skeletal ha’s (most common ms ha’s  originate in upper neck and are felt along the back of the head or from temporal mandibular jt and felt on the side of the head). Caffeine withdrawal ha’s are another type of ha. Assuming the correct diagnosis of migraines… they are often associated with food triggers. In my experience avoiding foods that are high in tyramines( a naturally occurring compound which is also a breakdown product of the amino acid tyramine) is particularly helpful. It is particularly high in processed foods and increases in leftovers. The challenge is that it occurs in both animal products such as cheeses, processed and most meats and plant products such as nuts and snow peas. The best approach is to go on a plant based diet and when you get a migraine to list everything that you ate or drank within previous 24 hours. It does get tricky because it is the amount consumed that seems to be critical not stress. When under stress people tend to eat out, skip meals(thereby eating more when they eat) or eat leftovers. My patients always preferred avoiding migraines as opposed to treating them although they would occasionally “push the envelope a little for foods like chocolate”. Caffeine which is actually added to some old migraine treatments like “cafergot” seems to be able to trigger migraines but it can depend on the amount, type and brewing characteristics. Good luck.

  • guest

    Lowrie, if you’re addicted to caffeine, for sure you’re going to get a migraine if you don’t have your coffee and you won’t be able to function until you get your fix. It’s not a nice situation and so, I wouldn’t start drinking coffee if you don’t now.
    I don’t see anything wrong with a banana. It’s a good source of vitamin B6 which neither apples nor berries have, manganese which apples don’t have and has equivalent amounts of dietary fiber and vitamin C to an apple or berries.   

  • Dixter

    What about cholesterol in instant coffee?

    • DrDons

      Coffee as with all plants don’t contain cholesterol. I don’t drink instant coffee but unless they add some animal product to it it should contain no cholesterol.

  • Jaxon

    it seems to me that any food or beverage that is habit forming and causes withdrawal symptoms when removed from the diet should never be considered as health promoting.

    Abstention from such products seems like a “no brainer’ to me.

  • Carlo

    Hello Mr. Greger,
    Are you going to post any video on the possible reason for the higher incidence of colorectal cancer among vegetarians in the EPIC-Oxford study? Thank you!

    — Carlo

  • Doron Regev

    Green Tea should be avoided when receiving treatment with Velcade for MM Cancer – it is proven to reduce the positive results. 

  • Pingback: Quick Collard Wraps & Blogging Schedule()

  • bdr613

    I’ve reviewed Ray Kurzweil’s health guide.  Kurzweil is a very smart guy and very science literate, so in my mind there is, at least, a presumption of credibility.  He recommends an alkaline diet, and specifically recommends drinking alkalyzed water and avoiding coffee because of its high acidity.  Are you aware of any peer-reviewed studies supporting or opposing this recommendation?  Thanks very much, and thank you for your extremely credible and purely science-based recommendations.  

    • Toxins

      Dr. Greger covers alkalized water here

      as for alkalinity,

      Almost all plant foods will produce a potential renal acid
      load (PRAL) that is negative (alkaline) because of the amino acid
      makeup. Grains are very slightly acidic but most animal products are
      several times times more acidic. The PRAL can be calculated with this
      formula PRAL = 0.49(Protein) + 0.037(Phosphorus) – 0.021(Potassium) –
      0.026(Magnesium) – 0.013(Calcium).


      You can go to the USDA nutrition database and calculate the
      alkalinity or acidity of certain foods this way using a 100 gram
      serving sample.


      Here are a list of common plant foods. A negative number indicates alkalinity whereas positive means acidity.


      Cereals, oats, regular cooked with water, w/o salt/ 2.18

      Bananas, raw/ -6.93

      Blueberries, raw/ -1.04

      Rice, brown, long-grain, cooked/ 2.18

      Broccoli, cooked, boiled, drained, w/o salt/ -3.57

      Cauliflower, cooked, boiled, drained, w/o salt / -1.33

      Carrots, cooked, boiled, drained, w/o salt/ -4.10

      Peaches, raw/ -3.11

      Beans, kidney, cooked, boiled, w/o salt/ -0.69

      Kale, raw/ -8.34


      Animal Foods


      Chicken, broilers or fryers, breast, meat only, cooked, roasted/ 17.30

      Egg, whole, raw, fresh/ 9.43

      Fish, salmon, Atlantic, wild, cooked, dry heat/ 7.57

      Beef, bottom sirloin, tri-tip, separable lean only, trimmed to 0″ fat, choice, cooked, roasted/ 12.79

      Cheese, cheddar/ 19.00


      As you can see, all animal foods are acidic. This acidity is bad for
      our bones as explained by this study. “In response to chronic acid
      stress such as is imposed by an acid-ash diet, cellular responses
      mobilize bone and calcium as a buffer.”


      This acidic environment increases the production of cortisol which further diminishes bone density.


      This chronic acid load people put on their body causes bone loss leading to osteoporosis later on in life.

  • Guest

     If coffee has some health benefits, it’s probably due to its high content of  chlorogenic acid, an antioxidant which in the amounts in coffee may hinder iron absorption. Foods with more reasonable amounts of chlorogenic acid include green tea, sunflower seeds, artichokes, blueberries, cilantro, carrots, tomatoes and peanuts. Coffee also has its downside. I agree with Jaxon ” that any food or beverage that is habit forming and causes
    withdrawal symptoms when removed from the diet should never be
    considered as health promoting. Abstention from such products seems like a “no brainer’ ” There are many foods and beverages, such as those above which are better to eat and drink

  • WholeFoodChomper

    I realize that this may be WAY too much information, but I find that drinking a cup of coffee makes me regular. :-o

  • Stephen Lucker Kelly

    I am little conflicted your other video seems to imply you have no problem with coffee but here you say drink green tea instead? Maybe it would be good to write in the description of the video that you think that while coffee isn’t that dangerous that there are better choices. As the video implies coffee is healthy. Maybe do a more recent video saying which drink is the healthiest to drink… or the top selection of drinks that are best. And to remind people balance is key. Drinking multiple drinks.

  • thrasymachus

    Hi Dr. Greger,

    I noticed your articles about coffee:

    However you are missing an elementary factor that could explain why people would live longer while consuming coffee despite it being bad for you:
    Those who consume the most coffee tend to have higher incomes. These population studies are biased because comparatively wealthier professionals drink more coffee. For example, lower tier jobs often don’t have break rooms or areas with a coffee maker available and you cannot just make a cup and drink it anyway even if you have an on-site coffee maker. It is well known that having more wealth and higher job autonomy leads to better health outcomes because such people have more control over their lives, they have more optimism, stronger self-belief and also much less stress, but the poor have everything against them in those regards. See Susan Rosenthal’s free e-book “Power and Powerlessness”:
    for more detail about how economic factors and workplace autonomy impact health.

    Here is evidence of the income disparity involved in coffee consumption:
    “Demographic and Preferences of Coffee Drinkers in America”

    “Coffee Use Increases with Household Income
    “Seventy percent of Americans who report annual household incomes of $150,000+ drink coffee compared with 54% of those with household income less than $25,000.”

    • WholeFoodChomper

      You make some fantastic and very important points. Thanks for bringing the economy of health to this forum’s attention. I, for one, appreciate it.

  • Darryl Roy
  • Ingrid

    Dr. Greger,
    What can you tell us about acrylamide in coffee? The American Cancer Society says acrylamide can be found in “potato products, grain products, and coffee.” Thank you.

  • Tobias Brown

    What about the coffee substitutes often based on roasted chicory roots?