Iron Issues and Anemia
It is a well accepted idea that iron absorption and anemia can be altered by malabsoptive surgeries such as Roux En Y Gastric Bypass (RYGB) and biliopancreatic diversion with duodenal switch (BPD-DS). There are multiple variables involved that have both negative and positive effects on iron absorption but the overall incidence of anemia increase from an average of 12% before surgery to about 23% afterward. To understand this you must have a basic understanding of how iron is absorbed.
Iron is absorbed best in the first part of the intestine (doedenum jejunum). This part of the intestine is usually bypassed by RYGB and BPD giving a negative effect on absorption. Also, iron is better absorbed in an acid environment, which is also reduced by RYGB and BPD. Iron is easier to absorb in the form of “heme” which is found in meats and thus tends to be negative effect as meat consumption decreases after surgery. These negative effects are counter-balanced by, and even overcome by, a reduction in systemic inflammation that occurs as a result of the dramatic weight loss. This reduction of systematic inflammation appears to have multiple beneficial effects. It is such a powerful effect that after 24-48 months most patients will actually see increase in serum iron levels!
So, why then do we have to take all this damn iron? Despite the actual improvement in serum iron there is still an overall increase in the incidence of anemia, some of which appears to be iron related. The anemias that develop after weight loss may not be secondary to actual absorption of iron as much as a product of the altered metabolism or processing of iron once it is in your body. Unfortunately, the metabolism of iron and effects of weight loss surgery on iron storage and metabolism are poorly understood at this time. It is known that premenopausal women are the most likely population to develop anemia after weight loss surgery.
Dr. K. Robert Williams Jr.
New Life for Bariatric Surgery