Coffee, Caffeine and Type 2 Diabetes

There has been extensive research into whether consuming coffee (caffeine) is safe for those with type 2 diabetes as well as whether or not coffee could help prevent diabetes.

With the ever rising population of people suffering with type 2 diabetes, it’s good to hear that the diabetic or potential diabetic has a friend in coffee.

A healthy diet, low in sugar and refined carbs, is still the number one dietary measure to treat or reduce the risk for diabetes.  Most research shows that coffee can be part of a diet that’s designed to prevent, treat, and/or possibly reverse type 2 diabetes.

Type 2 Diabetes and Coffee Research Studies

  1. A study published by the American Diabetes Association showed that those who drink coffee have lower sugar and insulin levels. It also appears that regular coffee is better than decaffeinated, so coffee could even prevent the onset of type 2 diabetes.15 overweight but otherwise healthy men were given either decaf coffee, a placebo, or the chemicals chlorogenic acid and trigonelline dissolved in water, which are two of the main antioxidants in coffee. The participants’ glucose and insulin levels were checked after consumption of each throughout the trial period. The only sample that showed lowered sugar and insulin levels was the chlorogenic acid and trigonelline solution group. Src.
  2. Another study analyzed much the latest research concerning diabetes and coffee consumption and was conducted by Harvard’s Dr. Frank Hu. His team found that the risk of type II diabetes decreased by 9% for each daily cup of coffee consumed. Decaf coffee decreased risk by 6% per cup. Src.
  3. An 11 year study looked at the diabetes and coffee risk association in postmenopausal women. They found that women who consumed 6 cups of coffee had a 22% lower risk of developing type 2 diabetes. Src.
  4. An 18 year Swedish study also showed a greater degree of decreased risk among women who consume the most cups of coffee daily. The Swedes are one of the highest coffee consumers in the world. Src.
  5. “Nineteen of 22 epidemiological studies concluded that long-term consumption of coffee, both caffeinated and decaffeinated, can reduce the risk of type 2 diabetes, but several investigators have warned that the caffeine in caffeinated coffee can impair glucose metabolism” from Diabetes Journals.
  6. The newer study is from the Harvard School of Public Health and it showed that type 2 diabetes risk decreases with every cup of coffee consumed. People who increased their coffee consumption by one cup saw an 11% decreased risk of type 2 diabetes. However, those that decreased their coffee consumption by one cup saw a 17% increase in risk. Src.
  7. Yet another study out of Denmark showed that coffee consumption doesn’t increase type 2 diabetes risk nor obesity risk for even the staunchest of coffee drinkers. 93,000 people’s coffee habits were analyzed for the study and there was no association between coffee consumption obesity, and diabetes. The study.

Decaf Coffee Not as Helpful

coffee-and-diabetesAlthough, caffeinated coffee does seem to offer the most protection, it isn’t likely due to the caffeine. Coffee is actually rich in antioxidants.

In the decaffeination process these antioxidants are also removed to much lower concentrations along with the caffeine.

This explains why the same results weren’t observed with the decaf samples. Therefore, it does seem to be best to have regular, full-test coffee that’s been un-messed around with if you want to experience less type 2 diabetes risk or help in treating this form of diabetes.

Caffeine Lowers Blood Glucose Levels During Exercise

Researchers found that when people with type 2 diabetes use caffeine prior to exercise it lowers their blood glucose levels more.

Study participants given 1 mg of caffeine per 1 kg of body weight had on average a 75 mg/dL increased drop in blood sugar compared with those who did not have the caffeine.

Good or Bad?

Good if you are trying to naturally lower your blood sugar with diet and exercise.

Bad if you are on insulin and in danger of your blood sugar dropping too low.

The Bottom Line?

This is good news for coffee drinkers or those that would be at risk of developing type 2 diabetes. You can drink all the coffee you want, but we would advise that you learn to drink it black to experience the full benefits. Also be sure to not go beyond established daily caffeine safe levels.

Adding sugar and creamer no doubt quickly reduces some of coffee’s type 2 diabetes protective benefits.

If you have diabetes always consult your physician before making any changes to your diet.

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  • Nick

    Not a big fan of straight coffee myself. I usually put some milk & sugar-free DaVinci syrup in it.

  • Brad – Coffee addict

    If this is true I’ll NEVER have Diabetes!

  • Sarah
  • SohnMan

    Thank you for posting this response, caffeine does most certainly affect diabetics that are on insulin as it inhibits insulin. I have personally experienced this when battling migraines.

  • Michael McKinley

    Before taking this article a face value, please check out the link that Sarah has included below! In fact I’ll copy it at the end of this post. Pay particular note of the difference in the credibility to the references cited between the two articles.
    I am not diabetic but several of my family are, and I am hypoglycemic (so I still get to prick myself and watch the glucose levels). We have noticed for some time the effect of caffeine on blood glucose levels for for both diabetics and hypoglycemics.
    Am I saying this article is wrong? No, I have not done actual clinical studies my self, nor have I personally reviewed the material presented. I am simply giving my personal observations of the effect for my family and myself, and pointing you to the references cited and cautioning you to make an informed decision.
    Here is that link so kindly added by Sarah (below)

  • Thanks for the input. Delving into the articles cited in the MayoClinic piece show the complexity surrounding this issue – one in particular showing caffeinated coffee may disrupt glucose management (

    However the majority of the larger epidemiological studies do show positive outcomes:

    “Nineteen of 22 epidemiological studies concluded that long-term
    consumption of coffee, both caffeinated and decaffeinated, can reduce
    the risk of type 2 diabetes, but several investigators have warned that
    the caffeine in caffeinated coffee can impair glucose metabolism”

    This is from Diabetes Journal –

    Totally agree with making an informed decision, and if you see blood sugar spiking after caffeine, then just stick with the low-gi meal.

  • S Sales

    I went to the “researchers” link to read about the single study done in California earlier in 2014. It does suggest that 40 minutes of exercise at a 40% HR followed by 10 minute cool-down and sampling after consuming 1mg caffeine per Kg body mass will significantly lower blood glucose levels in type II diabetics. However, how high did the glucose levels rise after drinking the coffee and what was the net change in glucose, before coffee and after the post workout measurement? When I drink 7 ounces of plain black decaf my glucose rises a minimum of 40 units… and much higher if I eat any food along with the coffee. Also, they need to explain what a 40% HR means and how to attain that level. Also, since my decaf should be less than 20mg, what HR and time must I exercise to offset those 20mg? More studies, including decaf are needed to verify repeatability…otherwise, this is dubious. Just something to talk about over a cup of coffee.

  • jane soder

    I can stand plain coffee,myself, I make what my hubby calls “Mexican coffee”, I add coco, Stevie, 2% milk, 1/2 t cinnimon

  • jane soder

    the cinnamon helps diabetes as well. i read it in” Green Pharmacy’ by a former Surgeon General

  • lukman

    Good for me decaf!! I fund usefull for daibetics!!

  • UrbanKorea

    Person who has Type 2 diabetes is it safe to drink coffee?? does drinking coffee causes pancreatic cancer???

  • Ted

    Some say that coffee messes with their insulin levels, while other diabetics drink it in moderation without problems. I’m not aware of any studies that have linked coffee to pancreatic cancer.

  • UrbanKorea

    Thank U. Good to hear. Coffee not linked to pancreatic cancer.

  • Smith

    Hi, you just posted an important information for us.After diagnosed in Type 2 diabetes we have faced lots of problems.So if we find some new way to protect our health from diabetes it will be great for us. I just joined a facebook group yesterday.I have seen that their have lots of type 2 diabetes patients. They are sharing own-own problems and experience after diagnosed in type 2 diabetes. Others patients also commenting on their post and helping them. It is a strong community to share our experience about T2 diabetes.Here is that group it’s a closed group.I was really worried for some of my problems but these group members are really friendly and shared their experience with me, Now I am happy to get their help. Because I am not alone.We are all of the diabetes patients want to live happily and we are each of others. We want to stay strong with type 2 diabetes. Please publish more important information about type 2 diabetes and let’s know us everything. Thank you

  • Russ Miller

    As a type 2 diabetic (16 years now), I can assure you that caffeinated ANYTHING is not good for you! After drinking two cups (my mug 2 cups), I experience a spike in my B/G that seems to last all day. My glipizide did not help. I conducted my own research, using myself as a guinea pig. Caffeine is no bueno. Period. I am forced to drink unleaded coffee and green tea (naturally decaffed). A word to the wise. Don’t take anybody’s word for anything. Do you own research.

  • maias

    You don’t mention whether you take sugar in your coffee. Bte, what is ‘unleaded coffee’

Last Modified: July 20, 2015


  • Nordestgaard, A. T., Thomsen, M., & Nordestgaard, B. G. (2015). Coffee intake and risk of obesity, metabolic syndrome and type 2 diabetes: a Mendelian randomization study. International journal of epidemiology, dyv083.
  • Rosengren, A., Dotevall, A., Wilhelmsen, L., Thelle, D., & Johansson, S. (2004). Coffee and incidence of diabetes in Swedish women: a prospective 18‐year follow‐up study. Journal of internal medicine, 255(1), 89-95.