I am wondering why you are supplementing Vit D into the milk. Most milk is fortified with it, even soy milk. As for C and B, those are easily attained through a well balanced diet, as mentioned below. I am a big believer in attaining vitamins and minerals from a healthy diet, because the balance of minerals and vitamins in food is perfect. When we start messing around with supplements, it gets trickier. For example, some vitamins work by igniting a reaction in another mineral. When eaten out of order without the mineral, the vitamin is useless, or even harmful. I read a study the other day that said that vitamin C supplements can destroy dietary B vitamins, so to take supplements at least 2 hours after eating. Anyways, I could go on and on about nutrition, and can't really answer your original question. But, I feel that you are invested in learning more, and would like to recommend a very powerful book about nutrition- "Healing with Whole Foods: Asian Traditions and Modern Nutrition", written by Paul Pitchford. It is a comprehensive nutritional bible, so to speak. I have been reading mine for years. It really breaks down the best way to prepare foods for optimum balance and nutritional benefit. It gives you all the information and allows you to make your own choices. (it is NOT a new age hippie book, but the author is centered in Sattva ideals) It covers everything from meat-based to vegetarian to raw foodist diets and their preparation. And children's diets too. It is written from a very respectful perspective and is almost 800 pages, and includes MANY recipes and techniques of food preparation. Hope that was helpful:)