How can you make sure you don't get vitamin deficiency?

Eat real foods. Eating a variety of fresh, unprocessed foods can ensure that you are getting vitamins, minerals and phytonutrients that are part of a balanced diet. Eat fruits and vegetables in all the colors of the rainbow (not artificial colors) - the colors show that the food has phyto (plant-based) nutrients. To make sure you cover all your bases you can also take a food-based vitamin-mineral supplement.