I love peer-reviewed journal articles. There are so many of them. If you search hard enough you're sure to find something positive about your favorite nutritional vice.
Perhaps reading something positive about what you're eating has a placebo affect. Your brain tells you it's good for you - so your body follows suit. Wine, coffee, chocolate, full-fat dairy... just take your pick.
My vice is dark chocolate.
Fortunately for me, a recent review of research compared the impact of cocoa and tea on blood pressure and found that dark chocolate may lower blood pressure.