Supports Healthy Immune Function. Gluten Milk/Casein and Preservative Free. Vitamin C is an essential antioxidant nutrient needed for the building of collagen maintaining teeth and gum tissue health and the normal functioning of the body's natural defenses. . Carlson Milk-C contains calcium ascorbate a buffered form of vitamin C that dentists prefer. The acidity of ascorbic acid can leach calcium from teeth causing gradual dental erosion. Ascorbic acid may also be difficult for a sensitive stomach to digest. Calcium ascorbate is a non-acidic form of vitamin C that is gentle to the teeth and mild in the stomach.