Vitamin E status among bariatric surgery patients: a systematic review.

Vitamin E, a fat-soluble vitamin with antioxidant properties, is thought to modulate enzymes involved in signal transduction, affect gene expression, and have immunomodulatory capabilities. Severe vitamin E deficiency is associated with neuronal disorders, impaired immune response, hemolytic anemia, and oxidative-based disorders. Patients who undergo bariatric surgery (BS), especially malabsorptive procedures, are at greater risk of developing fat-soluble vitamin deficiencies. Current data on vitamin E statuses among BS patients are limited. Therefore, this systematic review has summarized the scientific literature on vitamin E and examined its status among patients following different types of BS. Searches of the MEDLINE and Embase databases were performed, followed by hand-searching of reference lists from all relevant papers. Of the 671 initially identified articles, 24 met the inclusion criteria: 1 study on adjustable gastric banding patients (n = 21), 4 studies on sleeve gastrectomy patients (n = 173), 12 studies on Roux-en-Y gastric bypass patients (n = 689) and 12 studies on biliopancreatic diversion with or without duodenal switch (n = 799) or single anastomosis duodeno-ileal bypass with sleeve gastrectomy patients (n = 163). Results suggest that patients who undergo malabsorptive procedures are at higher risk of developing vitamin E deficiency, although clinical manifestations of vitamin E deficits following BS are rarely documented. The optimal dose of vitamin E supplementation required for prevention of deficiency or for treatment following BS has yet to be established. Future observational and intervention studies are needed to bridge the gaps in existing knowledge.