Vitamin D. Polarised light micrograph of crystals of vitamin D. Vitamin D is fat-soluble, and is found in foods such as animal fats, milk, butter and eggs. Vitamin D is also produced by the body when in sunlight or ultraviolet radiation. The absence of vitamin D leads to rickets. It is also used in the treatment of osteomalacia and dental caries. Vitamin D also has a role in digestion, being necessary for the absorption of calcium and phosphorus in the gut. Magnification x35 at 6x7cm size.