American Society for Metabolic and Bariatric Surgery Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients

Surg Obes Relat Dis. 2017 May;13(5):727-741. doi: 10.1016/j.soard.2016.12.018. Epub 2017 Jan 19.


Background: Optimizing postoperative patient outcomes and nutritional status begins preoperatively. Patients should be educated before and after weight loss surgery (WLS) on the expected nutrient deficiencies associated with alterations in physiology. Although surgery can exacerbate preexisting nutrient deficiencies, preoperative screening for vitamin deficiencies has not been the norm in the majority of WLS practices. Screening is important because it is common for patients who present for WLS to have at least 1 vitamin or mineral deficiency preoperatively.

Objectives: The focus of this paper is to update the 2008 American Society for Metabolic and Bariatric Surgery Nutrition in Bariatric Surgery Guidelines with key micronutrient research in laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, biliopancreatic diversion, and biliopancreatic diversion/duodenal switch.

Methods: Four questions regarding recommendations for preoperative and postoperative screening of nutrient deficiencies, preventative supplementation, and repletion of nutrient deficiencies in pre-WLS patients have been applied to specific micronutrients (vitamins B1 and B12; folate; iron; vitamins A, E, and K; calcium; vitamin D; copper; and zinc).

Results: Out of the 554 articles identified as meeting preliminary search criteria, 402 were reviewed in detail. There are 92 recommendations in this update, 79 new recommendations and an additional 13 that have not changed since 2008. Each recommendation has a corresponding graded level of evidence, from grade A through D.

Conclusions: Data continue to suggest that the prevalence of micronutrient deficiencies is increasing, while monitoring of patients at follow-up is decreasing. This document should be viewed as a guideline for a reasonable approach to patient nutritional care based on the most recent research, scientific evidence, resources, and information available. It is the responsibility of the registered dietitian nutritionist and WLS program to determine individual variations as they relate to patient nutritional care.

Publication types

  • Practice Guideline

MeSH terms

  • Avitaminosis / prevention & control*
  • Bariatric Surgery / methods*
  • Humans
  • Micronutrients / administration & dosage
  • Micronutrients / deficiency*
  • Nutritional Status
  • Nutritional Support / methods*
  • Vitamins / administration & dosage*


  • Micronutrients
  • Vitamins