A small glass of red wine a day is enough to provide diabetics with their daily dose of a drug needed to combat the disease, scientists have shown.
Twelve different wines were selected for the study according to different grape varieties, sun exposure of the grapes, maceration time and oak wood contact. Prior to analysis, the team studied the polyphenol compositions of the wines. As they expected, the amount of phenolic compounds and polyphenols, the most abundant antioxidants in our diet, was lower in white wines.
The main purpose of the study was to isolate the anti-diabetic properties of the selected wines. The team, from the University of Natural Resources and Applied Life Sciences, Vienna, published their research in the latest edition of the Royal Society of Chemistry journal Food and Function.
Through wine technology, the concentration of polyphenols, which play a key role in the health benefits of wine by acting as antioxidants that prevent cell damage, can be controlled, according to the scientists. As grape skins contain a wide variety of polyphenols in considerable amounts, red wines are usually rich in these compounds.
The scientists have shed light on this area by examining polyphenols in a dozen Austrian wines - 10 red and two white. The researchers assessed polyphenol activity towards a receptor called PPAR-gamma (peroxisome proliferator-activated receptor gamma). This receptor is present in many tissues in the body, and is primarily involved in the development of fat cells, in energy storage, and in modifying lipid and glucose levels in the blood, making it a key target for drugs for cardiovascular and metabolic diseases.
When the team ran PPAR-gamma binding assays, they found that not only did these compounds bind to the receptor, but that the wines contained enough of them to rival the activity of the potent drug rosiglitazone, which is used to treat type 2 diabetes.
Researcher Alfred Zoechling said: "From our study, using rosiglitazone, the anti-diabetic drug which works as an insulin sensitizer, as a reference compound, we could calculate the relative binding affinity of each wine. 4-8mg is the recommended daily dose for treating type 2 diabetes using rosiglitazone. 100ml of the tested red wines was equivalent to approximately 1.8-18mg of rosiglitazone. This volume contained an activity equivalent of at least a quarter of, and up to four times, the daily dose of this potent anti-diabetes drug. A drawback to red wine consumption, which must be taken into account for type 2 diabetes and obesity patients, is their comparatively high sugar and alcohol content."
Moderate consumption leading to beneficial effects on metabolic syndrome will correspond to about 10-20g of alcohol per day for women and to 20-30g of alcohol per day for men, say the scientists. The term "moderate" defined as a glass per day, varying between 100ml and 200ml. Two month studies have also shown that wine consumption leads to statistically significant weight loss, their paper reports.
Notes for editors
. The two white wines selected were Neuberger and Rotgipfler; the reds included one Pinot Noir, two St Laurent, three Zweigelt and four Blaufränkisch.
Red wine: A source of potent ligands for peroxisome proliferator-activated receptor gamma A Zoechling, F Liebner and A Jungbauer, Food Funct., 2010 DOI: 10.1039/c0fo00086h