Contact: Anna Kokavec, Ph.D.
La Trobe University
Alcoholism: Clinical & Experimental Research
Moderate alcohol consumption after meals can decrease levels of insulin
- Insulin is a hormone that allows blood glucose to provide energy to most of the body's cells.
- A lack of insulin can effectively cause some cells to "starve," leading to serious health consequences such as diabetes.
- New research shows that drinking a moderate amount of white wine on its own after a meal can cause levels of insulin to drop almost immediately.
Insulin is a hormone that allows blood glucose to provide energy to most of the body's cells. New research published in the November issue of Alcoholism: Clinical & Experimental Research shows that drinking a moderate amount of white wine on its own after a meal can cause levels of insulin to drop almost immediately.
"A small to moderate amount of alcohol is accepted and indeed often recommended as beneficial to one's cardiac health," said Anna Kokavec, a research psychologist affiliated with La Trobe University in Bundoora, Australia and first author of the study. "However, only a limited number of studies have assessed the effect of consuming readily available alcoholic products on major processes in the human body."
Eating foods high in carbohydrates will normally increase blood-glucose levels for several hours, which in turn, encourages insulin production by the pancreas. Insulin enables glucose, the body's chief source of energy, to gain entry into most of the body's cells located outside of the brain. A lack of insulin can effectively cause some cells to "starve," leading to serious health consequences such as diabetes.
"We know that drinking alcohol can affect the body's production of insulin," said Kokavec. "However, researchers in the past have obtained mixed results and it is only now becoming clear that the effect of alcohol on insulin may depend on the presence or absence of food. Given the discrepancy in the insulin data, the association between food and insulin production, and the important role of insulin in energy production and usage, we felt that the effect of drinking a popular alcoholic beverage such as white wine on insulin production under variable nutritional conditions warranted investigation."
Researchers examined eight non-diabetic males between the ages of 19 and 22 years. All were required to consume pizza and a soft drink for 45 minutes, and then slowly drink three standard units of white wine (10 grams of alcohol each; 30 grams total) during a 90-minute period following their meal. Plasma glucose and plasma insulin levels were assessed during and following the alcohol-consumption period.
"Our results showed that drinking a moderate amount of white wine on its own after a meal can cause the level of insulin to drop almost immediately," said Kokavec. "This was accompanied by a similar lowering of the blood-glucose level and, in some individuals, to a very dangerously low level. The level of insulin after little more than one glass of white wine was similar to the level of insulin usually seen before a meal. When this is considered together with the blood-glucose finding, it suggests that drinking white wine on its own may promote a pseudo-diabetic condition, changing the way the body produces and uses glucose. This could have serious consequences because some of the cells in the body could be starved of energy, which could ultimately lead to disease."
Kokavec added that these findings also support their previously published theory that alcohol may activate a new energy system that was thought, until recently, to exist only in plants and other organisms that do not require oxygen.
"The glyoxylate cycle is an energy system that can convert fat into carbohydrate," she said. "The glyoxylate cycle does not require thiamine, utilizes acetate as an energy source, and can be switched off by glucose. If alcohol does indeed activate the glyoxylate cycle in the human liver, then this could offer an explanation for alcohol-related fatty liver, thiamine deficiency, alteration in energy metabolism under fasting conditions, and lack of appetite for carbohydrates [that are] found in alcoholics, the reasons for which have baffled researchers for years."
Furthermore, said Kokavec, "present results highlight the need to strictly control for nutritional factors when designing alcohol research as nutritional status may be a confounding factor that is contributing to variability in the alcohol literature. In addition, given the possibility that alcohol may activate the glyoxylate cycle, an energy pathway that can be switched off by glucose, it may be important for scientists to specifically control for the presence of carbohydrates when investigating the effect of alcohol."
Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. The co-author of the ACER paper was Simon F. Crowe of the School of Psychological Science at La Trobe University in Bundoora, Australia. The study was funded by an Australian Research Council Large Grant.