(WebMD) - Drinking a daily glass of red wine not only tastes good to many people, but it's also good for the bacteria lining your large intestine. A new Spanish study suggests that sipping about 9 ounces of Merlot or a low-alcohol red wine changed the mix of good and bad bacteria typically found in the colon in ways that can benefit your health. Bacteria may sound like a bad thing to have in your intestinal tract, but having a balanced mix of them actually helps to digest food, regulate immune function, and produce vitamin K (which plays a key role in helping the blood clot). Since the study results showed that Merlot and low-alcohol red wine had similar positive effects on intestinal bacteria, researchers suspect it's not due to the alcohol but to the polyphenol compounds found in the wine.