Milk, regeneration properties for devil fruit users? Does milk offer regenerative capabilities? I've never seen it in the anime but in the newest chapter 858 of the manga the following scene is shown.


Now, I haven't been reading the manga long I just started reading after the dressrosa arc but I watched the anime up to that point and I don't recall ever seeing anything like this. 

Is this a devil fruit thing? A gag?
It is a gag and actually just applies for Brook and Luffy. The calcium in the milk is good for bones and Brook is nothing but bones (It is mentioned at Thriller Bark, even in the anime) and Luffy has huge regenerative powers whenever he eats or drinks (remember Alabasta when he pumped water in his almost dead dry body).