In such a short trial, it is unlikely that any vitamin or mineral deficiencies would develop, unless you have an underlying medical condition. Calcium, vitamin D, and vitamin B12 are the ones brought up most frequently by doctors and dairy advocates. Check our Calcium Guide for more detailed information on natural sources and supplementation of this mineral. Our best source of vitamin D is the sun, but if you are unable to get a few rays each day, then consider a supplement. Vitamin B12 is abundant in meat. If you are a vegetarian, consider supplementation. Nutritional yeast, a popular ingredient in vegan cheeses and cheese sauces, is also rich in B12. If you have any concerns, or a medical condition, consult with a physician before undergoing a change in diet.