Vitamin B12 helps your body use fat and carbohydrates for energy and make new protein. It is also important for normal blood , cells, and nerves. Most people get enough vitamin B12 in their diet, but a deficiency may occur in certain health conditions (e.g., poor nutrition , stomach /intestinal problems, infection, cancer ). Serious
vitamin B12 deficiency may result in anemia ,
stomach problems , and nerve damage ...Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects...so nothing much to worry.