What causes iron deficiency after gastric bypass surgery?

Iron deficiency is a side effect that results from the changes made during the surgery. Most of the iron from foods is absorbed in the first part of your small intestine (duodenum). But after a gastric bypass procedure, food bypasses the duodenum. This can lead to iron deficiency and other nutrition problems.


The amount of iron in a standard multivitamin (18 mg) may not be enough to prevent anemia if you have this kind of surgery.  You will need to take more iron if your iron is low after a gastric bypass.


Who is at risk for iron deficiency after gastric bypass surgery?

Iron deficiency is more common in women who have this surgery after menopause. It can occur in more than half of women in this age group. Men who have had gastric bypass also may get iron deficiency. But it happens much less often in men.

Key points about iron deficiency after gastric bypass surgery

  • Iron deficiency and anemia are common after a gastric bypass or other weight-loss surgery, especially in women.

  • You can get iron deficiency and anemia years or decades after your gastric bypass surgery.

  • You will need to monitor your level of iron and other nutrients for the rest of your life

  • You will likely need intravenous iron infusions to improve your symptoms

What are the symptoms of iron deficiency after gastric bypass surgery?

  • Lack of energy or tiredness (fatigue)

  • Weakness

  • Headache

  • Rapid heartbeat

  • Hair loss

  • Brittle nails

  • Shortness of breath

  • Chest pain

  • Strange pounding sensation in your ears

  • Craving for ice or clay