I guess I haven't done my research, but I can't see any reason not to drink DI water. It's pure water, pH 7. It will become more acid in contact with co2 over time. I have drank in often. I guess I will do some more reading on it.
I've been using it for cooking and drinking for about 2yrs now. I've seen my well water hit 15+ppm of No3. I think people under estimate the amount of minerals we get from our food.