I am taking elevit as well and had constipation on and off.
I stopped taking it in the morning and now take it at night time just after dinner.
I also make sure that I have 3 pieces of fresh fruit a day and high fibre cereal (sultana bran) or bread for breakfast.
I am now as regular as clockwork.
Hope these simple steps help.
They only problem now is making sure that i don't need rennie within 2 hours of taking the elevit!!!