Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial

Abstract

BackgroundCoffee consumption has been associated with a lower risk of type 2 diabetes in prospective cohort studies, but the underlying mechanisms remain unclear. The aim of this study was to evaluate the effects of regular and decaffeinated coffee on biological risk factors for type 2 diabetes.MethodsRandomized parallel-arm intervention conducted in 45 healthy overweight volunteers who were nonsmokers and regular coffee consumers. Participants were assigned to consumption of 5 cups (177 mL each) per day of instant caffeinated coffee, decaffeinated coffee, or no coffee (i.e., water) for 8 weeks.ResultsAverage age was 40 years and body mass index was 29.5 kg/m2. Compared with consuming no coffee, consumption of caffeinated coffee increased adiponectin (difference in change from baseline 1.4 μg/mL; 95% CI: 0.2, 2.7) and interleukin-6 (difference: 60%; 95% CI: 8, 138) concentrations and consumption of decaffeinated coffee decreased fetuin-A concentrations (difference: -20%; 95% CI: -35, -1). For measures of glucose tolerance, insulin sensitivity, and insulin secretion, no significant differences were found between treatment groups.ConclusionsAlthough no changes in glycemia and/or insulin sensitivity were observed after 8 weeks of coffee consumption, improvements in adipocyte and liver function as indicated by changes in adiponectin and fetuin-A concentrations may contribute to beneficial metabolic effects of long-term coffee consumption.Trial Registrationclinicaltrials.gov NCT00305097

The Effects of Caffeinated and Decaffeinated Coffee on Sex Hormone-Binding Globulin and Endogenous Sex Hormone Levels: A Randomized Controlled Trial

“…In this randomized controlled trial with caffeinated and decaffeinated coffee interventions, we did not find evidence of a consistent effect on SHBG levels in overweight men or women. This contrasts with the beneficial effects of coffee consumption on adiponectin and fetuin-A levels previously reported in this trial [9], suggesting that the SHBG level is not the major intermediate of the putative effect of coffee consumption on a lower risk of T2DM. Our findings necessitate further examination in a larger intervention trial of the effects of coffee on sex hormones to elucidate if this is a potential intermediary …”

Cardiometabolic effects of two coffee blends differing in content for major constituents in overweight adults: a randomized controlled trial

“…Published intervention trials include comparisons of coffee consumption versus abstention [9], caffeinated versus decaffeinated coffee [10,11] or pure caffeine [12], coffees differing in brewing type [13], or coffees enriched or reduced in special coffee constituents [14]. The roasting process has an important impact on the content of coffee constituents [15,16].…”

Mechanisms and biological effects of Caffeine on substrate metabolism homeostasis: A systematic review

“…This study also showed that the administration of caffeine was able to control the catecholamine levels (adrenaline and noradrenaline) in this group, reducing them up to 124% when comparing to the values of pre-consumption and further decreased sympathetic nervous system stimulation. Wedick et al (2011) evaluated the effect of the consumption of 5 cups of coffee (caffeinated and decaffeinated) for 8 weeks, over DMT2 risk factors, in 45 men over weighed. No alteration was observed in the following parameters: ISI, oral glucose tolerance test (OGTT) and insulin secretion.…”

“…On long-term, studies demonstrated that caffeine did not alter (Wedick et al, 2011) or increased glucose tolerance (Guarino et al, 2013) and insulin sensibility (Yamauchi et al, 2010).…”