It's interesting to note that there currently are no requirements for nutritional information to be listed on wine labels (nor beer or liquor for that matter). While there are groups lobbying for increased disclosure of such information, for the time being we as consumers are in the dark regarding the exact nutritional content of any given wine. That being said, there are some generalizations that we can make.

According to the FDA, the average 5-ounce glass of red wine contains approximately 106 calories. White wine tends to be a bit lower, averaging 100. Carbohydrates are low for both red and white wine, averaging about 2.5g for red and 1.2g for white. Most of the calories in wine come from the alcohol, so higher alcohol wines will have more calories than lower alcohol wines. Also, sweeter wines have higher residual sugar content and thus will also be slightly higher in calories, all other things being equal.

As far as vitamins and minerals are concerned, wine typically contains only trace amounts. However, there are other substances in wine that may potentially be beneficial, most notably antioxidants and the recently highly-touted resveratrol, both of which have been linked to disease prevention.