OBJECTIVE -Epidemiological studies suggest that moderate alcohol consumers have enhanced insulin sensitivity and a reduced risk of type 2 diabetes. Adiponectin, an adipocytederived plasma protein, has been found to be negatively associated with adiposity and positively associated with insulin sensitivity. Moderate alcohol consumption may increase adiponectin, which in turn causes a decrease of tumor necrosis factor (TNF)-␣. A decreased TNF-␣ level may consequently increase insulin sensitivity.RESEARCH DESIGN AND METHODS -To test this hypothesis, we performed a randomized crossover partially diet-controlled study. A total of 23 healthy middle-aged male subjects consumed daily four glasses of whisky (40 g ethanol) or tap water with dinner during two successive periods of 17 days.RESULTS -Moderate alcohol consumption increased plasma adiponectin level (11%; P ϭ 0.0002) but did not affect plasma TNF-␣ level. An increase in insulin sensitivity index was observed in an insulin-resistant subgroup (21%; P ϭ 0.11), which positively correlated with the relative alcohol-induced increase in plasma adiponectin level (r ϭ 0.73, P ϭ 0.02).CONCLUSIONS -The experimental results are in agreement with observational data. Moderate alcohol consumption improved insulin sensitivity in relatively insulin-resistant middle-aged men, an effect that may be mediated through alcohol-induced increases in adiponectin. Diabetes Care 27:184 -189, 2004C ross-sectional (1-7) and large prospective (8 -13) studies have shown that moderate alcohol consumption is associated with enhanced insulin sensitivity and a reduced incidence of type 2 diabetes.Recent hyperinsulinemic-euglycemic clamp (14,15) and other (16) studies have revealed that a high level of adiponectin, an adipocyte-derived plasma protein, is closely related to increased insulin sensitivity. This suggests that dysregulation of adiponectin may be relevant to the development of insulin resistance (17). Plasma adiponectin levels are indeed significantly lower in subjects with obesity (16,18) and type 2 diabetes (19). A recent study showed that low fasting plasma adiponectin concentrations are associated with high basal and low insulin-stimulated skeletal muscle insulin receptor tyrosine phosphorylation, which is one possible cause of decreased insulin sensitivity (20). High levels of tumor necrosis factor (TNF)-␣ have long been implicated to cause high basal tyrosine phosphorylation of the skeletal insulin receptor (21) and in turn insulin resistance (22,23). In vitro studies showed that adiponectin reduced both TNF-␣ production and TNF-␣-induced biological effects (17,24,25).To date, the mechanism for increased insulin sensitivity in moderate alcohol consumers is not well understood. We hypothesized that moderate alcohol consumption affects circulating adiponectin and, via this pathway, the TNF-␣ level, which has direct effects on the tyrosine phosphorylation of the skeletal insulin receptor and thus insulin resistance. This hypothesis was tested by measuring plasma adiponectin and TNF-␣ l...

Objective: To evaluate the effect of moderate alcohol consumption on the acute phase proteins C-reactive protein and fibrinogen. Design: Randomized, diet-controlled, cross-over study. Setting: The study was performed at TNO Nutrition and Food Research, Zeist, The Netherlands. Subjects: Ten middle-aged men and 10 postmenopausal women, all apparently healthy, non-smoking and moderate alcohol drinkers, were included. One women dropped out because of a treatment-unrelated cause. The remaining 19 subjects finished the experiment successfully. Interventions: Men consumed four glasses and women consumed three glasses of beer or no-alcohol beer (control) with evening dinner during two successive periods of 3 weeks. The total diet was supplied to the subjects and had essentially the same composition during these 6 weeks. Before each treatment there was a 1 week washout period to compensate for possible carry-over effects. Results: Plasma C-reactive protein and fibrinogen levels were decreased by 35% (P ¼ 0.02) and 12.4% (P 0.001), respectively, after 3 weeks' consumption of beer, as compared to no-alcohol beer consumption. Conclusions: Moderate alcohol consumption significantly decreased plasma C-reactive protein and fibrinogen levels. An antiinflammatory action of alcohol may help explain the link between moderate alcohol consumption and lower cardiovascular disease risk.

A systematic review was conducted to assess the evidence linking beer consumption to abdominal and general obesity. Following a systematic search strategy, 35 eligible observational studies and 12 experimental studies were identified. Regarding abdominal obesity, most observational data pointed towards a positive association or no association between beer intake and waist circumference or waist-to-hip ratio in men, whereas results for women were inconsistent. Data from a subset of studies indicated that beer intake > 500 mL/day may be positively associated with abdominal obesity. Regarding general obesity, most observational studies pointed towards an inverse association or no association between beer intake and body weight in women and a positive association or no association in men. Data from six experimental studies in men, in which alcoholic beer was compared with low-alcoholic beer, suggested that consumption of alcoholic beer (for 21-126 days) results in weight gain (0.73 kg; P < 0.0001), but data from four studies comparing intake of alcoholic beer with intake of no alcohol did not support this finding. Generally, experimental studies had low-quality data. In conclusion, the available data provide inadequate scientific evidence to assess whether beer intake at moderate levels (<500 mL/day) is associated with general or abdominal obesity. Higher intake, however, may be positively associated with abdominal obesity.