The Skinny on IDA after Weight Loss Surgery

Margaret M. Furtado, MS, RDN, LDN

Weight loss surgery has never been more popular, and with high-profile celebrities and politicians, including well-liked New Jersey Governor, Chris Christie, who underwent gastric banding surgery recently, it’s likely its popularity will continue to soar.  The benefits often outweigh the risks when it comes to weight loss surgeries, but it is still important to fully understand potential nutritional risks, including iron deficiency anemia.

Of all the bariatric surgery procedures, including gastric bypass, biliopancreatic diversion and sleeve gastrectomy, gastric banding is the only surgery that just restricts food, as opposed to removing portions of organs. Therefore, gastric banding holds the lowest risk for nutritional deficiencies, including iron.  However, no surgery is risk-free. One of the common risks among weight loss surgery patients, including banding patients, is low iron levels following surgery, especially if patients are not eating iron-rich foods after the procedure.  On the other hand, gastric bypass surgery, and to a lesser extent sleeve gastrectomy (aka “the sleeve”), hold much higher risk for iron deficiency anemia (IDA). Here’s why:

  • With gastric bypass (GBP), the chief sites of iron absorption in the body – the first part of the small intestine (duodenum) and beginning of the second part of the small intestine (jejunum) –  are bypassed.  Additionally, with GBP your stomach goes from football-sized to a “pouch” the size of a small egg, significantly decreasing the available acid that is so vital for optimal iron absorption.  The sleeve procedure does not affect the small intestine at all, and allows for a larger, “banana-sized” stomach, but still significantly reduces the amount of stomach acid vital for superior iron absorption.
  • Intolerance to red meat is common among all the bariatric procedures, including GBP, the sleeve, and the band, with overall meat intolerance cited in research to be greater than 50% as far out as 4 years after surgery.  Since red meat is rich in high-quality (heme) iron which is easily absorbed, this increases the risk of iron deficiency anemia.
  • Women who undergo bariatric surgery who are menstruating may be at particularly high risk for IDA due to the inherent losses of iron. 

Red flags for IDA that weight loss surgery patient should be on the lookout for include:

  • Pagophagia (craving and chewing ice)
  • PICA (craving for non-edible items, including dirt, clay, paper, and cornstarch)
  • Fatigue
  • Shortness-of-breath (worsens with exercise)
  • Cold feet and hands
  • Unusually pale skin
  • Pale conjunctivae (the mucous membranes just under your eyelashes)
  • Dizziness
  • Chest pains (particularly if you don’t have heart disease)

Here are some suggestions for how you can prevent and/or reverse IDA:

  • Consider a cast-iron skillet (you’ll scrape iron right into your food with cooking!)
  • Ensure you include vitamin C with your iron supplement (vitamin C, aka ascorbic acid, heightens availability for absorption).
  • Don’t assume your multi-vitamin is meeting your iron needs. Senior, silver and/or 50-plus multivitamin/mineral supplements contain only 8 mgs of iron, compared to the standard 18 mgs per dose, and “gummy-type” multivitamins are typically incomplete and devoid of iron.
  • Avoid taking calcium or drinking tea within two hours of consuming iron since they interact to lessen absorption.
  • Consider daily consumption of high-iron foods, including: liver (highest iron naturally in foods) red meat (tender and moist, for better tolerance), chicken, turkey, liver, clams, lentils, beans, pumpkin seeds, and iron-fortified cereals.  Vegetarian sources of iron contain a less bio-available kind of iron (non-heme) that is not as high-quality or absorbable as the heme iron found in animal protein sources.  What’s more, vegetables, including spinach, may contain phytates, which are found naturally in foods and bind iron.  However, including vitamin C and/or cooking with a cast-iron skillet will help enhance iron absorption, regardless of the quality of iron.

The information in this article is for informational purposes only and not intended to provide medical advice. You should direct all questions about your health to your health care provider.

Margaret M. Furtado, MS, RDN, LDN, has more than 20 years’ experience in clinical nutrition and dietetics. She has spent the last several years working in the field of bariatric nutrition and obesity medicine at Centers of Excellence in Bariatric Surgery, such as Tufts Medical Center, Massachusetts General Hospital's Weight Center, the Johns Hopkins Center for Bariatric Surgery, and the University of Maryland Medical Center.


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