**5.1 Anemia**

Anemia is common after BS. The prevalence of macrocytic and microcytic anemia is 52% post LSG, 64% post RYGB and 39% after biliopancreatic diversion [45]. Patients with mild anemia post BS are likely to be asymptomatic; however, when the anemia worsens, patients could present with symptoms, such as fatigue, pallor, and dyspnea on exertion [6]. Post-bariatric anemia is in most cases due to iron deficiency, along with vitamin B12 deficiency as a secondary cause. Other causes of nutritional anemias after malabsorptive BS includes folate, protein, copper, selenium, and zinc deficiencies. Therefore, these factors should be evaluated if routine screening for iron-deficiency anemia is negative [10].
