Does bariatric surgery cause vitamin A, B1, C or E deficiency? A systematic review

Background: The restrictive and/or malabsorptive nature of bariatric surgery may increase the risk for micronutrient deficiencies. This systematic review aimed to identify and critique the evidence for vitamin A, B1, C or E deficiencies associated with bariatric surgery. Methods: This review utilised PRISMA and MOOSE frameworks with NHMRC evidence hierarchy and the American Dietetic Association bias tool to assess the quality of articles. Results: Twenty-one articles were included and once critiqued all studies were of level IV grade and neutral or negative in quality. The relevance of measuring micronutrient supplementation and inflammatory markers for validity of serum vitamins is absent within the literature. Conclusions: Future research is needed to investigate the risk of deficiency for these procedures with focus on confounders to serum micronutrients