Resveratrol in the red wine you drink could reduce the amount of unhealthy cholesterol in your blood. In southern France, where the average diet includes wine and large amounts of butter, liver and other fatty foods, fewer people develop cardiovascular disease than in the United States. Resveratrol could partly account for the better health of French citizens. Resveratrol content varies with the vintage, but some American wines top the scale.
Resveratrol and Cholesterol
Resveratrol in wine protects the high-density and low-density lipoproteins responsible for circulating cholesterol through your system. LDL carries cholesterol from your liver to body tissues, and HDL carries cholesterol back to your liver for recycling. When LDL levels outrace HDL, cholesterol levels rise. When free radicals oxidize LDL, this fatty compound becomes sticky and forms plaque on the walls of your arteries. Resveratrol prevents oxidation of both LDL and HDL cholesterol. Proper diet, regular exercise, and other positive life choices can control LDL and HDL levels, and drinking moderate amounts of red wine offers extra protection from cardiovascular disease.
Only the skin of grapes actually contains resveratrol. Resveratrol belongs to a group of chemical compounds called flavonoids that give color and flavor to fruits and vegetables. Polyphenols such as flavonoids and tannins scavenge the free radical molecules that cause DNA damage in cells by oxidizing and mutating tissue. Other sources of the antioxidant resveratrol include peanuts, blueberries and purple grape juice. Resveratrol accumulates in red wine because red wine ferments longer as a mixture of juice, pulp and grape skins. White wine contains little resveratrol because the primary fermentation uses only juice.
Since flavonoids contribute color to both grapes and wine, color provides a rough guide to resveratrol content. Dark, full-bodied red wines such as Burgundy, merlot and cabernet sauvignon contain more flavonoids than light rose or zinfandel. The different varieties of wine grapes that create the unique flavors and bouquets of wine also contribute different amounts of flavonoids to the wine. Climate and geography influence resveratrol levels, since grapevines generate resveratrol to combat fungal diseases. Higher humidity in New York vineyards fosters higher levels of resveratrol, according to Professor Leroy Creasy of Cornell University. The drier climate of California results in less resveratrol.
Professor Creasy analyzed the resveratrol content of 111 wines including wines from California and foreign countries. Seventy of the wines came from New York vineyards, and most of the wines were 1995 vintages. New York wines ranked highest in overall resveratrol content. Wines of average resveratrol content contain concentrations of 3 to 4 micromolar, while wines considered high in resveratrol measure 5 micromolar or better. On average, New York red wines measured 7.5 micromolar and California red wines achieved 5.0. New York pinot noir averaged highest at 13.6, followed by California pinot noir at 10.1. Cabernet sauvignon ranked second overall, with merlot the third best.