A formulation and method for treating or preventing a deficiency of certain nutrients in patients undergoing a therapy in which one or more proton pump inhibitors is administered. The formulation includes:a) 1000 mcg of B12, as methylcobalamin;b) 150 mg of Vitamin C;c) 500 mg of calcium citrate;d) 15 mg of elemental iron in a ferrous form.The formulation may also include 10-50 mg of a proton pump inhibitor.