OBJECTIVE -Population data suggest that alcohol consumption may influence the risk of diabetes in a biphasic manner, but this has not been tested by any controlled interventions. The object of this study was to determine whether reducing alcohol intake in moderate-to-heavy drinkers (40 -110 g/day) results in improvement in insulin sensitivity.
RESEARCH DESIGN AND METHODS-A 4-week run-in period where subjects maintained their usual drinking pattern was followed by randomization to a two-way cross-over intervention study. In each of two 4-week treatment interventions, subjects either substituted their usual alcohol intake with a 0.9% alcohol beer or maintained their usual alcohol intake. At the end of each 4-week period, insulin sensitivity as determined by the low-dose insulin glucose infusion test and the homeostasis model assessment (HOMA) score, and biomarkers of alcohol consumption (␥-glutamyl transpeptidase [␥-GT] and HDL cholesterol) were measured.RESULTS -A total of 16 healthy men aged 51.0 Ϯ 2.7 (mean Ϯ SEM) years with a BMI of 26.4 Ϯ 0.61 kg/m 2 completed the study. There was a large reduction in alcohol intake (72.4 Ϯ 5.0 vs. 7.9 Ϯ 1.6 g/day, P Ͻ 0.001) and significant reductions in ␥-GT (geometric mean .2], P Ͻ 0.01) and HDL cholesterol (1.36 Ϯ 0.07 vs. 1.13 Ϯ 0.07 mmol/l, P Ͻ 0.001). There was no effect of alcohol on insulin sensitivity index (ISI), fasting insulin, glucose, or HOMA score.CONCLUSIONS -A substantial reduction in alcohol intake from 7.2 to 0.8 standard drinks per day in healthy men did not change insulin sensitivity as measured by ISI or HOMA score.
Diabetes Care 26:608 -612, 2003P resently, it is difficult to simply define overall effects of alcohol on the insulin-glucose axis. Acutely, alcohol impairs insulin sensitivity in shortterm experiments using insulin-glucose clamp techniques (1-5). In contrast, evidence from cross-sectional populationbased studies suggests an association between chronic alcohol exposure and improvement in insulin sensitivity (6), but such studies are rendered inherently weak by the potential for confounding by other variables affecting insulin sensitivity, especially adiposity (7-10). Although there have been no prospective studies evaluating the effect of long-term alcohol use on insulin sensitivity, per se, there have been a number of studies investigating whether there is any association between alcohol use at baseline and subsequent incidence of type 2 diabetes. Many of these studies found that light (ϳ3-18 g/day) (11-13) to moderate (18 -49 g/day) (14 -16) alcohol use was associated with a reduced risk for the development of diabetes. Two of these studies (11,13) were hampered due to the very limited number of subjects with moderate to heavy intake (i.e., Ͼ20 g/day, equivalent to more than two standard drinks per day). In the prospective Rancho Bernardo Study (17), the upper tertile of drinkers consumed Ͼ25 g alcohol/day, whereas in the Atherosclerosis Risk in Communities (ARIC) Study (18), Ͼ8% of the male population consumed Ͼ36 g alcohol/day. Data from...