What a great question! I've also heard anecdotal reports that those who are lactose intolerant may have trouble absorbing nutrients such as Vitamin D, but I can't say that I've seen that to be medically confirmed. However, I have heard that those who are severely lactose intolerant even have trouble consuming lactose free milk, especially the quantity that would be necessary to get one's needed Vitamin D intake if that is the person's primary source of the crucial vitamin. (Depending on one's age, that might be four or more cups per day!) For this reason one might consider exploring alternatives such as taking Vitamin D supplements or engaging in regular sun exposure (about 10 minutes a few times a week on the face and hands, without sunscreen, may be sufficient -- but issues such as climate and longitude can affect this). You may want to discuss with a medical professional which of these options (or a combination) might be best for this particular situation. Good luck!