Vitamin D is recommended in the treatment of several diseases. It may prevent preaclamsia by improving kidney function, cancer by controlling abnormal multiplication of cancer cells, diabetes mellitus by controlling insulin production, hyperparathyroidism by reducing parathyroid numbers, osteomalacia by improving bone and muscle strength, hypophosphatemia by controlling the phosphates in the body, hypocalcaemia by preventing abnormal deposition of calcium, and renal osteodystrophy by regulating calcium content and fibromyalgia.