You will need to take vitamins and minerals following surgery to compensate for the fact that bypassing part of the intestine prevents your body from absorbing not only calories, thus resulting in the desired weight loss, but also some of the vitamins and minerals that are vital for your body to function normally.
The symptoms of vitamin and mineral deficiency can rarely appear early after surgery, can be quite pronounced, and can include bone pain, hallucinations and weakness. If symptoms appear at this early stage then the problem can often be resolved with treatment. More commonly, however, symptoms do not begin to appear until some time after surgery, even several years.
In many cases, the administration of such vitamins and minerals as B12, thiamine and copper can certainly help to reduce or eliminate symptoms, but in a significant number of patients some of the symptoms can be permanent.
Prevention of these problems is far better than cure. This is easily done by regular, daily use of a multivitamin, as well as calcium supplementation (usually starting six months after surgery), and a regular injection of vitamin B12 (to be given by your GP). This needs to continue lifelong.
Gastric bypass surgery is a major surgical procedure that requires you to not only make significant changes to your lifestyle in the weeks and months following surgery, but for the remainder of your life. One of these lifestyle changes is the need to take vitamin and mineral supplements. Failure to do this can have significant consequences.