*3.5.1 Iron*

Iron deficiency with or without anemia is frequently observed after BS [10]. The incidence after LAGB and LSG ranges between 14 to 18% [10]. The prevalence after RYGB and BPB/DS is 51.3% and 15% respectively [34, 35]. Several mechanisms lead to iron deficiency post BS. First, iron malabsorption can occur as a result of the bypassing of the duodenum and proximal jejunum post BS where most of iron absorption occurs. Second, decreased gastric acidity and accelerated gastric emptying impair the reduction of iron from the ferric (Fe 3+) to the absorbable ferrous state (Fe 2+). Third is the decreased intake of iron-rich foods (meats, vegetables) post BS. Finally, the absorption of iron may be affected by the interaction with

other nutritional supplements (e.g., calcium) [10, 14]. Menstruating women are at higher risk for iron deficiency and anemia, specially patients with polymenorrhagia [25]. Other risk factors for iron deficiency include malabsorptive procedures, young age, preoperative anemia and low baseline ferritin level [36]. The clinical features of iron deficiency are summarized in **Table 1**. The measurement of serum ferritin is the best diagnostic test for detecting iron deficiency and a better indicator of iron body capacity as it becomes abnormal prior to the decrease in serum iron concentration [6]. Prophylactic iron supplementation is recommended after all types of BS to minimize the risk of deficiency [10]. Iron is usually included in oral multivitamin and mineral preparations with the inclusion of vitamin C, which will increase iron absorption [10]. They should not be taken along together with calcium supplements as such supplements may affect the absorption of iron. Severe cases of iron deficiency anemia require intravenous iron or blood transfusion [36].
