Should I take vitamins and supplements after weight loss surgery?

Posted by Sharon Alfuth, R.N.
July 29, 2015


After weight loss surgery, your body may not absorb enough of certain vitamins and minerals — specifically, iron, vitamin B12, calcium and vitamin D. Long-term health complications, such as anemia, can develop due to a deficiency of iron or B12; neurological complications, such as memory loss or irritability from a lack of B12; and bone and kidney disease due to changes in the way your body absorbs calcium and vitamin D.

It is important that you take the following vitamins and supplements on a daily basis after weight loss surgery to prevent nutrient deficiencies.


Take a chewable multivitamin daily containing a minimum of 18 mg of iron. Brands that contain this formula include Trader Joe's, Flintstone and Centrum. Children’s chewable vitamins also can be taken in an adult dose by taking two tablets daily.


Take 1,500 mg calcium citrate or 2,000 mg calcium carbonate daily to prevent calcium deficiency and bone disease. To enhance absorption, take the calcium supplement as three divided doses at three different times a day. Calcium citrate is the preferred form of calcium. Do not take calcium at the same time as your multivitamin with iron, since the iron may affect calcium absorption.

Vitamin D

Take 800 to 1,000 international units (IU) of vitamin D daily. This total amount should be taken as 400 to 500 IU twice daily with your calcium supplement. If you prefer, you can take a combination calcium-vitamin D supplement as long as it contains the proper dosages.

Vitamin B12

Take 500 micrograms of vitamin B daily. This can be taken as a tablet under the tongue or monthly in an injection.

Just as important as taking these nutrients daily is having your vitamin and mineral levels checked annually.  Make sure your primary care provider is aware that you have had weight loss surgery and that these nutrients need to be checked with annual blood draws.

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