Muniya - I asked my mum and she said if you had a defiency in a vitamin and then these supplements will help you. If you eat a pretty balanced diet which most people do - you get all of these vitamins as a part of your daily food intake.
... and the way I eat - I don't think I am malnurished in anyway :)
My sister isn't malnourished either lol.. but vitamin A & D has really helped her hair and skin and Mashallah is shows.