It is quite popular that mixing different alcoholic drinks, especially wines (red and white), is particularly bad for your health. Well, at dinner it can happen to change many wines – from spumante to dessert wines, or even strong drinks – and you generally drink more compared to drinking only a kind of wine.
So what can be bad for you is drinking “too much”, not mixing. Our organism recognizes the alcohol it has to metabolize and eliminate, but doesn’t care about the source. Therefore what matters is the total amount of alcohol that you introduce in your body.