Are there health benefits of drinking red wine vinegar? Or if not drinking, merely using small amounts for salad dressings and other flavorings?
Well in terms of antioxidant content, red vinegar contains very little. In fact, if you were consuming the same amount (by weight) of iceberg lettuce, you would be getting more antioxidants. But that's not to say there aren't other health benefits. For starters, an entire cup of it has only 45 calories. If you're just putting a tablespoon or two on your salad, that's virtually zero calories. Another benefit is that it does contain trace amounts of iron and potassium, not a lot, but some is better than none. Lastly, there are a number of phytonutrients - things you won't find on the ingredient label, yet offer potential health advantages. Since this type of vinegar is made from grapes it may contain resveratrol. It's important to remember the "may" part because resveratrol is very sensitive to light, so if it's been stored in a clear bottle there's no telling how much, if any, is still active. Most of the antioxidants in the vinegar come from polyphenols.
Ultimately though, it's important remember that this is quite different from balsamic, which is a vinegar loaded with naturally occurring sugars. Contrast that to red wine vinegar, which does not have sugar in or so little, it's not enough to even list on the nutritional label. Perhaps the biggest medicinal miracle it can bring to your daily life though is weight loss, not from the vinegar itself but from the fact that it adds flavors to foods with almost no calories.
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010