Caffeine may make it tougher for people with diabetes to control their blood sugar, a new study shows.
The finding, published in February’s Diabetes Care, adds to the confusion about the role coffee plays in diabetes risk. Although caffeine has consistently been shown to affect blood sugar levels, several studies have shown that coffee drinkers are at lower risk for diabetes.
The latest findings about caffeine come from a small study by Duke University researchers who set out to determine if caffeine consumption can undermine a patient’s effort to manage diabetes. The researchers studied the effects of caffeine in 10 patients with Type 2 diabetes. The patients were already regular coffee drinkers and were trying to manage their diabetes without using insulin.
Small glucose detection devices implanted under the abdominal skin tracked the rise and fall of patients’ blood sugar levels. On various days, study participants took either caffeine pills containing the equivalent of about four cups of coffee or identical placebo pills. Neither the patients nor the person giving them the pills knew which capsules contained the caffeine and which contained the placebo.
When the patients ingested caffeine, their average daily blood sugar levels went up by 8 percent. After meals, their blood sugar levels rose even higher, shooting up as much as 26 percent after dinner.
The researchers don’t know exactly why caffeine appears to drive up blood sugar. Caffeine may interfere with the movement of glucose through the body, or it could stimulate the release of hormones known to boost blood sugar levels.
However, the data don’t necessarily mean that people with diabetes or at risk for it should stop drinking coffee. Several large observational studies have shown that coffee drinkers have a lower risk for diabetes. Researchers speculate that other compounds in the coffee have a beneficial effect and may blunt some of the negatives of caffeine.
The data suggest that people with diabetes probably shouldn’t drink caffeinated soft drinks or other caffeine-containing beverages. Coffee drinkers who are having trouble managing their diabetes should consider quitting or switching to decaf to see if it helps, study author James Lane, a professor of medical psychology at Duke University, told HealthDay news. “It’s a simple thing that might make their diabetes better,” said Dr. Lane.
Earlier this month, another study showed that too much caffeine during pregnancy raises the risk for miscarriage.
Update: Go to comment #46 to read Dr. Lane’s response to several reader comments.
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From 1 to 25 of 74 Comments
I’m wondering why they used 4-cup coffee equivalent caffeine pills and not 2-cup. Simply to make the result more obvious?
from TPP — It seemed to mirror the coffee drinking patterns of many people –two cups of coffee in the morning and two later in the day. But you’re right — if you just drink two cups of a coffee a day, you can’t really judge the effect based on this research.
— Kevin ShumFollowing on TPP’s response to Kevin Shum’s comment, I’d say that while you can’t draw a precise inference from the study to a two cups per day coffee drinker, it is far more convincing than the observational studies cited in the article. This is a placebo controlled trial, which measures a causal effect and ought to be given a lot more weight than a simple correlation.
From TPP — And another reader makes the point that serving size varies. In this study, the caffeine pills were equal to four 8 oz cups of coffee. So two-cup-a-day grande and venti coffee drinkers are getting an extra jolt.
— David ClingingsmithI’ve been managing my diabetes with diet and exercise for five years. After about three years, I started to notice unexplained spikes in my blood sugar, particularly at night. I finally figured out on my own that caffeine might be the problem. I switched to decaf tea (boring) and it solved the problem.
— Ellen BrewsterI’m type 2. Gave up drinking and smoking but no way will I give up caffeine.
— Brian RichardsBut that is the opposite of what Dr Atkins and the South Beach say. And it is why when I drink my morning coffee I don’t feel hungry for a while. But as someone wrote recently in the Times: the first study is always proven false.
— RichAh, cola….!!!
Now just another thing I can’t have.
SIGH!!!
— Taylor HallmanI have been a type 2 diabetic for 11 years now. My endocrinologist, CDE, and the American Diabetes Assn told me this information back then.
— simpsonIf you realize that for most people, a single mug of coffee approaches to measured cups, then a 4-cup (two mug) equivalent is probably accurate, if not low for many coffee drinkers. Especially considering the high caffeine levels in much coffee shop (read “Starbucks”) coffee, as compared to regular home-brew.
I need to see if my father read this blurb.
— Elisabeth40+ years ago in med school first year biochemistry I learned caffeine raised blood sugar. Makes sense avoiding caffeinated drinks help diabetics maintain blood sugar control.
— MARK KLEIN, M.D.All life leads to death — persons should should always be aware of this existential prerogative. Is
a rigorously spent risk free existence worth anything?
Excuse me, gotta go to the kitchen to get a cup of . . .
— David ChowesThe problem with this and so many other medical studies is what is causal mechanism? Just because caffeine and higher blood sugar appear to be related in this study other studies indicate that coffee lowers blood sugar! Since the study protocol, which used caffeine pills, eliminates other compounds in coffee, there is little direct comparison.
Remember the maxim that any statistics professor will tell you: correlation of two factors does not imply causation.
Unless these authors can provide an account of how coffee consumption by diabetics is causally related to higher blood pressure (e.g., by a convincing metabolic sequence of events) then these findings have to be taken with…a grain of salt.
— KevinThis study had a lead author psychologist, an N of 10, tested the effect in 1 day, and used caffeine, not coffee.
— RichardFlawed and irrelevant by design.
As usual they only do the study on Type 2 Diabetics, just like everything else related to diabetes. I guess it is true then that Type 1 diabetics like myself just don’t exist to the medical and pharmaceutical companies?
— GlendaI have started reading In Defense of Food, and think I know what it would say about this issue. Taking caffeine pills is not the same thing as drinking coffee. There may be other chemicals in the coffee (or tea) that balance out the effect of the caffeine.
— ConsumerAny info on what the placebos were? Kind of behind a wall.
— PhilInteresting.
Richard–the lead author is a Psychophysiologist, PhD, not a Clinical/Counseling PhD…distinctly different. Just because someone has their PhD is a discipline of Psychology doesn’t mean that they only practice psychoanalysis or that the research is defunct. Psychophysiologists use hard science to study body-mind relationships.
— LeighI guess those of us who polish off a pot of coffee and a half dozen diet drinks a day are toast, according to this study. Four cups of coffee barely gets me out of bed in the morning…
— Buzz HappyWas this study worth publishing in a scientific journal? The sample is too small(10 patients), there are many confounding factors(99.9%of people drink caffeine, not have the purified form inserted under the skin) and the conclusions are premature(only 10 people hardly makes a statistical statement).
— A.Snaiderman,MD,FRCPCShould NYT publish an article about such a study?
The public is getting innundated by “first released to the media” scientific studies, which can and do confound the lay person. Science ebbs and flows in it’s trends, as it should.
The long term results of large cohort,well designed studies that can be replicated by other researchers should be the ones commented upon and published in the non-medical media.
Or how about commenting on primary prevention interventions (diet, exercise,weight loss, vegetable and fruit intake, good sleep hygiene) which are perhaps more relevant to everyone, if not as “sexy” a piece of news as a new drug to control-but not cure- symptoms of an illness?
If there was ever a study of only 10 patients which were given a drug that CURED their AIDS or cancer or schizophrenia…by all means comment on it!
Otherwise,it all becomes static backgound noise in a cacophony of studies and confusing findings.
A.Snaiderman. MD,FRCPC, Toronto.
A note to all article and headline writers:
Studies and articles could do all diabetics a favor if they consistently noted with each quote of “diabetes” whether they are speaking of type I or type II. They truly are two different diseases. Banner headlines of “Caffeine May Hamper Diabetes Control” or “Weight Loss Surgery Can Cure Diabetes” do not refer to type I diabetics but I cannot tell you how many people think I can be cured of my type I diabetes. Having been treated successfully (for 4 years) as a type II diabetic then into a type I, I’ve seen the discrimination from both sides. I would like to see more articles that have the word diabetes or diabetic with regard to which type (or both) the article or study is referring.
V
— VictoriaUh oh. Maybe those three triplemochachinnolattes with a half cup of sugar, every day for the past 10 years was a really bad idea. (gotta sit down now, dizzy and legs starting to hurt)
— FedUp#11 Nice analysis. This study merely says that caffeine, by itself and not with other coffee or cola compounds, may hamper blood sugar control in diabetics.
If the authors wanted to draw conclusions about avoiding caffeinated coffee, they should have compared standardized preparations of caffeinated and decaffeinated coffee, or even capsules of caffeinated and decaffeinated coffee extracts.
Based on the published study it would be much too big a leap to recommend that diabetics avoid coffee.
— jackI’m with Mr. Chowes. I was going to skip the coffee this morning just to switch things up a bit, but now, well, I think I might double my dose just for kicks.
— Jennifer DriscollDiabetics are carrying a severe excess of tissue acidity, internally. This is a really important and fundamental concept to grasp.
Coffee and many other “foods” won’t help, and will hurt.
In regard to the study-at-hand, I concur that the study’s format and size make it extremely problematical, and I agree with Dr. Snaiderman in post #18.
HOWEVER I also want to state that there is a sound basis for eliminating caffeine and the otherwise ACIDIC drinks which contain it e.g. coffee, fermented teas, colas and all other sodas.
Green tea is problematical, as it has substantial health benefits, and is less acid, but it still has plenty of acidic components.
Diabetics need to strive for alkalinity in all their tissues, daily. The blood will take care of itself, and rob everything else, in order to keep you alive, but the rest of your tissues can be soaked in internal acid-rain.
Many physicians realize this is the basic, fundamental source of much disease and suffering.
You can read more in the work of Dr. Robert O. Young, PhD (pH Miracle series), Dr, Mark Hyman, MD (”Ultrametabolism”), Dr. Thomas Rau, MD (”The Swiss Secret”), Dr. Theodore Baroody, ND (”Alkalize or Die”), Professor Felicia Drury Kliment (”The Acid Alkaline Balance Diet”), Susan Brown PhD, CCN (”The Acid Alkaline Food Guide”) and Dr. Christopher Vasey, ND eminent French researcher (”The Acid Alkaline Diet for Optimal Health”).
You can keep up with this topic and many more affecting diabetics and learning about the Root Cause of all disease at my blog:
http://diabetesdietdialogue.wordpress.com
In my posts there, you will also find links to websites for quite a number of the authors mentioned above, too, in order to keep up with their current thinking or you can read about much of it in my blog, as time goes by.
The majority of the “foods” which contain caffeine are non-foods, and to be healthy, or to regain health, requires adjustment to that fact.
Additionally, the adrenal hormones triggered by caffeine are definitely not benign for their constant, detrimental, looping-impact on insulin.
Use the study and discussion here as a wake-up call.
Best to all —
— EmEm
http://diabetesdietdialogue.wordpress.com
I read this in a coffee shop away from work. I came back to comment. First, we need much larger studies and more of a sample size than this one before I can take this seriously. Second, I am not diabetic and my blood sugar is always well within normal. Third, I am tired of everything being declared bad when the smallest shreds of evidence is offered.
Taking caffeine pills is not drinking coffee. Coffee is better than soft drinks. Some teas have toxins too that are worse than anything in coffee. I would recommend thinking long and hard about decaffeinate coffee, it is not better and has issues not found in regular coffee.
Finally, pick your poison, coffee is not perfect but it is a known quantity that stacks up to be much better than any of the less studied alternatives.
Next year, I anticipate a “never mind” study to be published and we will have all be back here to discuss it as well.
— MarkGreat. so no pasta, rice, potatoes, bread, cake, cookies, candy, ice cream, and now, I can’t have my cup of Joe in the morning. I’m trading in my glucose meter for a luger.
— BobBy the way, thanks Dr. Snaiderman for your inightful note, accurately pointing out that this article should never have been written based on a study that should have never been published.