Alcohol may protect women from type II diabetes

Moderate alcohol consumption may prevent the development of type II diabetes in post-menopausal women and control blood sugar in those with type II diabetes. A team led by Dr Michael Davies and Dr Philip Taylor from the USDA’s Beltsville Human Nutrition Research Centre, Maryland, investigated the hypoglycaemic effects of alcohol in post-menopausal women (JAMA 2002;287:2559). . Increased prevalence of insulin resistance is associated with post-menopausal women and leads to hyperinsulinaemia (high concentrations of circulating blood glucose) and a greater risk of cardiovascular disease than in the premenopausal state. Moderate alcohol intake has also been shown to be cardioprotective, through a shift in lipid metabolism towards high density lipoproteins.

53 post-menopausal women completed the randomised crossover study, that compared the effects of 0, 15, and 30 grams per day of alcohol on fasting insulin, triglycerides, blood glucose concentrations and insulin sensitivity. 30 grams of ethanol are approximately equivalent to 4 units of alcohol. Eligibility criteria for the study included being aged 50 years or more, of good general health, postmenopausal for at least a year, no personal or family history of alcohol misuse, no use of hormone replacement therapy, and not taking any drugs that would interfere with carbohydrate or lipid metabolism.

Diet was controlled during the study and alcohol was provided as ethanol in orange juice. Each dietary period was followed by a 2-5 week washout period to eliminate any bias from previous treatment. Menus provided 54% of The results showed that 30 g/d reduced fasting insulin concentrations by 19% and triglyceride concentrations by 10% compared to an intake of 0 g/d ethanol. 15 g/d ethanol only affected the fasting triglyceride concentration, with an 8% reduction compared to 0 g/d ethanol.

However, while the study is interesting it is unclear if all the benefit could be attributed to the addition of alcohol rather than to the reduction in carbohydrate intake. The authors state: "By design total carbohydrate intake was reduced with increasing alcohol intake. Energy from carbohydrates decreased from 53% with 0g/d of alcohol to 42.2% with 30g/d of alcohol."

Moreover, it is unknown whether these results are specific to pure ethanol rather than to commercial drinks and it is unknown if these results could be replicated in diabetic woman on non controlled diets. Alcohol consumption contributes to hypoglycaemia because its metabolism inhibits gluceneogenesis in the liver. This study suggests that it may also have a role in reducing insulin resistance.