Hello there.
I can understand your concern.
These are all supplements and they need to be taken after food.
Calcium needs to be taken daily, vit D3 60k nneds to be taken once a week.
B-Complex daily and iron also daily.
Doesn't matter even if you take with milk.
But if you are taking iron preparations, then tea and coffee to be avoided.
Best regards.
Dr. Anil kumar jain.
Bangalore.