Caffeine - Beware

  1. Caffeine - Beware

    by John M. Berardi

    Coffee Drinkers Beware!

    While there were several interesting topics presented, including a lecture given by a MD/PhD and research superstar Wim Saris who confirmed all of my incessant ramblings about the value of protein and amino acids with glucose and maltodextrin in a post-workout drink, the topic I found most interesting was the research presented on caffeine/coffee and insulin sensitivity.

    For a while now I've been cautioning my clients and T-mag readers about the ill effects caffeine and typical thermogenic agents have on insulin sensitivity. Well, at the University of Guelph they've been investigating this issue intensively and here's what they found:

    1) Caffeine intake (in all of its forms) decreases whole body glucose disposal (carbohydrate uptake) by 15-30%.

    2) Caffeine intake decreases skeletal muscle glucose disposal by 50%.

    3) When consumed with a standard carbohydrate breakfast, caffeine decreases insulin sensitivity, leading to large increases in blood insulin. But even in the face of this insulin surge, blood glucose doesn't disappear at a normal rate. When the body can't take up carbohydrates properly (as when drinking coffee), it releases loads of insulin to help out. However, the coffee actually prevents the insulin from doing this job and you end up with high insulin and glucose. That, my friends, is the serum profile of the obese, type II diabetic.

    4) Caffeine decreases insulin sensitivity for at least three hours (this is the duration of the longest study they've performed), but the true duration of the effect isn't known. I speculate that it's at least five hours, the half life of caffeine.

    In this case, many people are probably walking around all day with impaired insulin sensitivity. If you're a coffee drinker you should realize that you're living your life like a diabetic except during the times that it could actually be diagnosed. When you go to the doc to see why you're so fat or you feel like crap (if you have any glucose or insulin tolerance problems), what do you have to do? You have to fast overnight and avoid coffee! So 99% of your waking life you're functionally diabetic and that 1% of the time when it really matters and can be diagnosed, you're not. No wonder experts suggest that 50% of North Americans are diabetics who aren't diagnosed as such.

    5) In one study, four groups were used to evaluate the effect of caffeine and glycemic index on insulin sensitivity.

    The first group got decaf and a low-GI breakfast. They saw a normal blood glucose and insulin response.

    The second group got decaf and a high-GI breakfast. They saw a bigger insulin and glucose response in the blood.

    However, when the low GI group got regular coffee with breakfast, their blood profile was worse than that of those who got the high-glycemic breakfast and decaf. Therefore coffee/caffeine can turn a low glycemic meal into a high glycemic meal!

    Finally, the group that drank coffee and had the high-glycemic meal ended up looking like diabetics.

    6) One interesting hypothesis generated at the seminar was as follows: In terms of insulin sensitivity, caffeine alone is worse than coffee and obviously (as seen above) coffee is worse than nothing. However, some people believe that certain substances in coffee (specific quinides) can actually increase glucose disposal and improve insulin sensitivity. While the quinide content of coffee isn't strong enough to counter the effects of the caffeine, the quinides in decaf coffee may actually increase glucose and insulin tolerance. This hypothesis still needs to be tested and proper doses have yet to be discussed; however, keep your eyes out for this research in the near future.

    So the final word on coffee and caffeine is this stay the heck away from it! The only way to minimize the damage it causes may be to drink your coffee with a very low carbohydrate meal and eat only low carb meals for the next few hours after your coffee intake. I know, I know, it now sucks to be a coffee drinker! But giving up your java may bring you some great health and physique benefits.

  2. Yeah I did some research on Pubmed for this a while back and these are what I found:

    Caffeine can decrease insulin sensitivity in humans.

    Keijzers GB, De Galan BE, Tack CJ, Smits P.

    Department of Internal Medicine, University Medical Center Nijmegen, 6500 HB Nijmegen, the Netherlands.

    OBJECTIVE: Caffeine is a central stimulant that increases the release of catecholamines. As a component of popular beverages, caffeine is widely used around the world. Its pharmacological effects are predominantly due to adenosine receptor antagonism and include release of catecholamines. We hypothesized that caffeine reduces insulin sensitivity, either due to catecholamines and/or as a result of blocking adenosine-mediated stimulation of peripheral glucose uptake. RESEARCH DESIGN AND METHODS: Hyperinsulinemic-euglycemic glucose clamps were used to assess insulin sensitivity. Caffeine or placebo was administered intravenously to 12 healthy volunteers in a randomized, double-blind, crossover design. Measurements included plasma levels of insulin, catecholamines, free fatty acids (FFAs), and hemodynamic parameters. Insulin sensitivity was calculated as whole-body glucose uptake corrected for the insulin concentration. In a second study, the adenosine reuptake inhibitor dipyridamole was tested using an identical protocol in 10 healthy subjects. RESULTS: Caffeine decreased insulin sensitivity by 15% (P < 0.05 vs. placebo). After caffeine administration, plasma FFAs increased (P < 0.05) and remained higher than during placebo. Plasma epinephrine increased fivefold (P < 0.0005), and smaller increases were recorded in plasma norepinephrine (P < 0.02) and blood pressure (P < 0.001). Dipyridamole did not alter insulin sensitivity and only increased plasma norepinephrine (P < 0.01). CONCLUSIONS: Caffeine can decrease insulin sensitivity in healthy humans, possibly as a result of elevated plasma epinephrine levels.Because dipyridamole did not affect glucose uptake, peripheral adenosine receptor antagonism does not appear to contribute to this effect.

    Publication Types:
    Clinical Trial
    Randomized Controlled Trial

    PMID: 11815511 [PubMed - indexed for MEDLINE]

  3. Caffeine-induced impairment of insulin action but not insulin signaling in human skeletal muscle is reduced by exercise.

    Thong FS, Derave W, Kiens B, Graham TE, Urso B, Wojtaszewski JF, Hansen BF, Richter EA.

    Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Canada. [email protected]

    We investigated the effects of caffeine ingestion on skeletal muscle glucose uptake, glycogen synthase (GS) activity, and insulin signaling intermediates during a 100-min euglycemic-hyperinsulinemic (100 microU/ml) clamp. On two occasions, seven men performed 1-h one-legged knee extensor exercise at 3 h before the clamp. Caffeine (5 mg/kg) or placebo was administered in a randomized, double-blind fashion 1 h before the clamp. During the clamp, whole-body glucose disposal was reduced (P < 0.05) in caffeine (37.5 +/- 3.1 micromol x min(-1) x kg(-1)) vs. placebo (54.1 +/- 2.9 micromol x min(-1) x kg(-1)). In accordance, the total area under the curve over 100 min (AUC(0--100 min)) for insulin-stimulated glucose uptake in caffeine was reduced (P < 0.05) by approximately 50% in rested and exercised muscle. Caffeine also reduced (P < 0.05) GS activity before and during insulin infusion in both legs. Exercise increased insulin sensitivity of leg glucose uptake in both caffeine and placebo. Insulin increased insulin receptor tyrosine kinase (IRTK), insulin receptor substrate 1-associated phosphatidylinositol (PI) 3-kinase activities, and Ser(473) phosphorylation of protein kinase B (PKB)/Akt significantly but similarly in rested and exercised legs. Furthermore, insulin significantly decreased glycogen synthase kinase-3alpha (GSK-3alpha) activity equally in both legs. Caffeine did not alter insulin signaling in either leg. Plasma epinephrine and muscle cAMP concentrations were increased in caffeine. We conclude that 1) caffeine impairs insulin-stimulated glucose uptake and GS activity in rested and exercised human skeletal muscle; 2) caffeine-induced impairment of insulin-stimulated muscle glucose uptake and downregulation of GS activity are not accompanied by alterations in IRTK, PI 3-kinase, PKB/Akt, or GSK-3alpha but may be associated with increases in epinephrine and intramuscular cAMP concentrations; and 3) exercise reduces the detrimental effects of caffeine on insulin action in muscle.

    Publication Types:
    Clinical Trial
    Randomized Controlled Trial

    PMID: 11872654 [PubMed - indexed for MEDLINE]

  4. The best defense against hypoglycemia is to recognize it: is caffeine useful?

    Watson J, Kerr D.

    Bournemouth Diabetes and Endocrine Centre, Royal Bournemouth Hospital, Castle Lane East, Bournemouth BH7 7DW, United Kingdom. [email protected]

    Caffeine, 1,3,7trimethylxanthine, is used by 80% of the adult population of the world in its various forms. Even the simple pleasure of consuming this socially acceptable drug has implications for the person with diabetes mellitus. Caffeine may increase an individual's sensitivity to hypoglycemia through the combined effects of reducing substrate delivery to the brain via constriction of the cerebral arteries, whilst simultaneously increasing brain glucose metabolism and augmenting catecholamine production. This article summarizes the evidence supporting the hypothesis that caffeine influences the perception of and physiological response to hypoglycemia. Under laboratory conditions, acute ingestion of caffeine markedly enhances the symptomatic and sympathoadrenal responses to hypoglycemia in both healthy volunteers and patients with type 1 diabetes. Recently a study of free-living people with type 1 diabetes showed that caffeine consumption increased the awareness of hypoglycemia. Caffeine has been associated with a number of negative effects and addiction. Most serious of these associations are ischemic heart disease and hypertension, the relationships have not been clearly established and the evidence to date is controversial. Thus we conclude that in modest doses, caffeine may be a useful adjuvant therapy for patients with hypoglycemia unawareness. For once here is a therapy which is inexpensive, safe, and remarkably popular with its consumers.

    Publication Types:
    Review, Tutorial

  5. Good posts EBE- Hope you dont mind, but I edited in a bit of color in the 1st one to stress the main points....

  6. ****, I better stop drinking that diet coke with lunch....

  7. Thanks guys... I've been saying for quite a while that caffeine is much worse than ephedrine, good articles.


  8. Not that I've done a study or am I trying to purposely contradict what the above studies state but my blood sugars seem to be more easily controlled when I drink coffee.

  9. Originally posted by YellowJacket

    However, when the low GI group got regular coffee with breakfast, their blood profile was worse than that of those who got the high-glycemic breakfast and decaf. Therefore coffee/caffeine can turn a low glycemic meal into a high glycemic meal!

    Finally, the group that drank coffee and had the high-glycemic meal ended up looking like diabetics.&nbsp;


    I'm thinking that this little tid-bit of research might prove to be invaluable for post-workout nutrition


    Read This Book!!: Anabolic Steroids and the Athlete by William N. Taylor M.D.

  10. Unfortunately for me, I can't function without my morning coffee!

  11. Interesting stuff. I avoid coffee/caffeine except as a stimulant (I consider it to be a drug) - sometimes I'll use an ECA stack, other times a cup of coffee before a workout. I do avoid taking carbs around the same time - I never felt right - now I know why!

  12. 4) Caffeine decreases insulin sensitivity for at least three hours (this is the duration of the longest study they've performed), but the true duration of the effect isn't known. I speculate that it's at least five hours, the half life of caffeine.

    Say if I were using a caffeine-containing fatburner while dieting, along with ALA... Would the ALA work against the caffiene in this case?


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