If you tend to wash rice before you cook it, that white stuff that comes off is the vitamins. Don't wash it, or better yet, buy brown rice. All the vitamins are there with the fiber naturally. Most of the major cereal companies, like Kellogg's and Post, fortify breakfast cereals with B vitamins. This offers a substantial dose and really does help meet the body's requirements.
All foods lose their vitamin potency when heated or exposed to light.
Meat loses from 25 to 40 percent of its vitamins during cooking. Milk stored in clear glass bottles loses up to 75 percent of riboflavin in three hours. When bread is baked, it loses from 15 to 20 percent of the thiamin during the process. It is estimated that 68 percent of the folic acid in wheat is removed when it is processed into white flour. Folate found in food is only half as efficient as the folic acid found in supplements and fortified foods.