Good afternoon @Barbara. With regards to the milk and grape juice, there appears to be a problem with mixing these two beverages together in that components in each will react and cause concretion of amino acids which will prevent uptake and absorption of these nutrients. In addition the acidity of the grape juice could cause the milk to curdle which may impair digestion and cause stomach upset in some people. As well milk will block the uptake of the grape juices polyphenols. The best recommendation to mitigate this would be to allow an hour between each beverage consumed, thus absorbing the nutrients from each unimpaired. Listen to your body on this one in terms of discomfort and time duration elapsed between each type of beverage.
Author
J.R.K