In the years following bariatric surgery the volume of food you are able to eat will be reduced. Due to the volume restriction of your stomach as well as the bypassing of any part of your digestive tract, it will be difficult to consume adequate amounts of various nutrients. You will be required to take vitamin and mineral supplements daily — for the rest of your life!

Gastric Bypass and Sleeve Gastrectomy Patients: take a high quality multivitamin; calcium citrate and vitamin D; vitamin B12 orally or injectable; extra iron if needed (see below)

  1. Daily multivitamin (start at discharge from hospital)
    • Any vitamin will work as long as it contains at least:

      • 400 mcg folate
      • 18mg iron
      • 15mg zinc
      • 5000 IU vitamin A
      • 30 IU vitamin E
      • 80 mcg vitamin K
      • 2mg copper
      • 1.5mg thiamine B1
    • Must be liquid or chewable while following the post-op liquid diet (3 weeks)
  2. Calcium citrate with vitamin D (start 3 weeks after surgery)
    • Bypass and Sleeve patients need 1500-2000mg of calcium citrate everyday
    • Chewable, or a petit version, until 3 months after surgery
    • Calcium citrate should be used for best absorption.
    • Do not take more than 500-600mg every 4 hours for best absorption
    • Separate calcium from any iron supplement by at least 2 hours
    • Recommend 2000-3000 IU of ergocalciferol daily (vitamin D3)
  3. Vitamin B12 (start 3 weeks after surgery)
    • A sublingual (under the tongue) form is recommended for best absorption.
    • Choose a dose of 350 mcg or greater. You may request a B12 injection from your primary care provider. These should be received monthly
  4. Iron (start at 3 weeks after surgery if you meet the criteria below in bold)
    • Women who have had gastric bypass or sleeve gastrectomy and are menstruating or have a history of anemia will need to take additional iron
    • A liquid form of iron is recommended for better absorption
    • 18-27mg elemental iron for a total of 50-100mg a day
    • Ferrous fumarate, ferrous sulfate and ferrous gluconate are the best absorbed forms of iron
    • Take with your multivitamin or a vitamin C for enhanced absorption
    • You may wish to take an over-the-counter stool softener such as Colace when starting iron supplementation as they may cause constipation.


Breaking It Down


Why does a deficiency occur?: Many types of calcium require stomach acid for absorption, and with less stomach you have less acid. In addition, calcium and vitamin D are best absorbed in the duodenum and proximal jejunum which may be bypassed. Also, vitamin D requires fat to be absorbed and after RYGB fat is not as well absorbed.

What are the symptoms?: When your body is low in calcium, it starts taking calcium from your bones. This can cause myalgias (muscle aches), arthralgias (joint aches), muscle weakness and fatigue.

How common is this?: Up to 70% of patients. You are more at risk over time.

What can I do?: Supplement with 1500-2000 mg/day of calcium citrate (calcium carbonate requires stomach acid to absorb the calcium) and 2000-3000 IU of vitamin D3.

B12 and FOLATE

Why does a deficiency occur?: After weight loss surgery the body has trouble separating B12 from the protein you eat. Also, the stomach makes a special protein called Intrinsic Factor which is necessary to absorb B12 and folate, and due to your surgery you make much less of it.

What are the symptoms?: Low B12 can cause weakness and fatigue, paresthesias (numbness/tingling), peripheral neuropathy (nerve damage in hands and feet), and demyelination of the corticospinal tract and dorsal columns (nerve damage in your spinal cord). Low folate can cause fatigue and is extremely important for pregnant women to prevent neural tube defects in infants. In addition, maintaining B12 and folate levels helps to suppress homocysteine levels. Homocysteine is an amino acid with direct toxic effects on vascular endothelium (the wall of blood vessels) and can lead to cardiovascular disease and strokes.

How common is this?: I can happen in up to 12-33% of patients

What can I do?: The goal is to keep B12 above 600 pg/mL and folate above 15 ng/mL. Make sure you supplement with 400 mcg per day of folate and at least 350 mcg per day of B12 sublingually or a monthly injection.


Why does a deficiency occur?: After surgery there is less gastric acid secretion to reduce iron into its ferrous state required for absorption. In the RYGB you also bypass the duodenum and proximal jejunum which eliminates the two main areas of iron absorption.

What are the symptoms?: Diminished exercise and work tolerance, impaired thermoregulation (always hot or cold), immune dysfunction, cognitive impairment (memory loss), and pica (a strong desire to eat ice).

How common is this?: It occurs in up to 32% of sleeve patients and up to 52% of RYGB patients.

What can I do?: Follow the recommendations above and supplement with at least 18mg of iron a day. Women who are menstruating or have anemia will need more. Taking vitamin C helps with iron absorption. Stool softeners can help decrease the constipation that commonly occurs with iron supplements.


Thiamine (B1): Thiamine deficiency (called Beriberi) can occur due to decreased absorption from the bypassed duodenum or from persistent vomiting. It can lead to a neurologic derangement called Wernike-Korsakoff syndrome characterized by ataxia (irregular coordination), ophthalmoplegia (eye muscle weakness), nystagmus (rapid irregular eye movements), and mental confusion. B1 deficiency is very rare. You can prevent it by making sure your daily multivitamin contains 1.5mg of thiamine.

Vitamin A, E, K: In addition to vitamin D, these vitamins require fat and bile to be absorbed. In a bypassed intestine they may not get absorbed as well. Vitamin A deficiency can cause night blindness. Vitamin E and K deficiency have no clinical effect. These are all very rare. You can prevent them by making sure your daily multivitamin has 5000 IU vitamin A, 20 IU of vitamin E, and 80 mcg of vitamin K.

Zinc and Copper: Zinc and copper deficiency is extremely rare and is usually from poor dietary habits. Low zinc levels can cause alopecia (hair loss — different than the expected hair loss after surgery). Low copper levels can cause symptoms similar to thiamine deficiency. To prevent these you should make sure your daily multivitamin contains 15mg zinc and 2mg copper.