B12 and Folic Acid

Living with Hemoglobin of 3.7 After Bariatric Surgery! Follow-up is Key to Preventing Adverse Outcomes

“…Vitamin B12 or cobalamin deficiency occurs in 26-70% of gastric bypass patients [25][26][28][29][30][31]. Absorption of cobalamin is a complex process involving a series of steps [28][29][30][31].…”

“…Absorption of cobalamin is a complex process involving a series of steps [28][29][30][31]. Pepsin and hydrochloric acid cleave B12 from food protein in the stomach as an initial step; free B12 binds to R factor from saliva and exits the stomach, where in the alkaline medium of the duodenum, B12 splits from R factor to bind to intrinsic factor outside the stomach.…”

“…The gastrointestinal epithelium also undergoes megaloblastic changes from B12 deficiency leading to secondary malabsorption and deficiency of B12 and other nutrients [28,[30][31]. B12 deficiency is easily correctable by replacement of the vitamin via the oral, intramuscular, intranasal, or sublingual routes.…”

“…While achlorhydria contributes predominantly to iron and B12 deficiency, folate absorption is also facilitated by hydrochloric acid, mainly in the proximal small bowel [30][31]. Folate deficiency is a serious threat for women who become pregnant after gastric bypass surgery as the deficiency may lead to neural tube defects in infants.…”