How does alcohol effect a person's kidneys if he has diabetes?

Okay in moderation: It is important to know that alcohol has no proven cardiovascular benefits. The french study that shows benefit with daily 2 oz of wine was biased by the fact that persons using wine, not beer, were better off financially i.e. Took meds, saw docs, had insurance. Note, neither grape juice, used in wine, and other alcohols have no benefit for heart. Remember, the french benefit from selling wine.

Hard to answer: Alcohol is not particularly toxic to kidneys. However, it is toxic to diabetics. Alcohol has twice the calories per gram as sugar, and makes control of diabetes very difficult when people are consuming excessive amounts of alcohol. Some "brittle" diabetics should not ever drink alcohol. The decreased control of diabetes in drinkers may increase the chance of diabetic kidney damage.