Zinc absorption and zinc status are reduced after Roux-en-Y gastric bypass: a randomized study using 2 supplements

Abstract

Background: Micronutrient deficiencies are common in patients undergoing gastric bypass. The effect of this type of surgery on zinc absorption and zinc status is not well known. Objective: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP) on zinc status and zinc absorption at different stages after surgery. We hypothesized that zinc status would be significantly impaired after surgery and that this impairment would be less severe in subjects receiving increased supplemental zinc. We also hypothesized that zinc absorption would be lower after surgery. Design: Anthropometric and body-composition variables and dietary and biochemical indexes of zinc status and zinc absorption were determined in 67 severe and morbidly obese women [mean (6SD) age: 36.9 6 9.8 y; BMI (in kg/m 2 ): 45.2 6 4.7] who underwent RYGBP. The subjects were randomly assigned to 1 of 2 vitamin-mineral supplementation groups. Measurements were made before and 6, 12, and 18 mo after surgery. Fifty-six subjects completed the 18-mo follow-up. Results: Mean plasma zinc, erythrocyte membrane alkaline phosphatase activity, and the size of the rapidly exchangeable zinc pool decreased after RYGBP. Percentage zinc absorption decreased significantly from 32.3% to 13.6% at 6 mo after RYGBP and to 21% at 18 mo after surgery. No effect of supplement type was observed. Conclusions: Zinc status is impaired after RYGBP, despite the finding that dietary plus supplemental zinc doubled recommended zinc intakes in healthy persons. Zinc absorption capacity is significantly reduced soon after RYGBP, with no major changes until 18 mo after surgery.

Zinc Deficiency after Gastric Bypass for Morbid Obesity: a Systematic Review

“…Authors suggested that this indicated an impairment in Zn absorption after RYGB. Ruz [15] et al confirmed that Z significantly impaired soon after RYGB and this persists at least until 18 months after surgery. In this study percentage Zn absorption decreased from 32.3 % before surgery to 13.6 % by 6 months after surgery.…”

“…It is also evident that RYGB leads to not just a reduction in intake of Zn [15][16] but also its absorption [15,19]. In the study by Ruz et al [15], dietary Zn intake was 9.1, 5.4, 6.4, and 7.2 mg/d before and 6, 12, and 18 months respectively after RYGB.…”

“…In the study by Ruz et al [15], dietary Zn intake was 9.1, 5.4, 6.4, and 7.2 mg/d before and 6, 12, and 18 months respectively after RYGB. Pires et al [16] found patients were consuming lower amount of Zn than required 6 months after surgery.…”

“…It is interesting as most of the studies reporting on asymptomatic Zn deficiencies have evaluated Zn levels in patients taking much less than this amount of Zn daily. For example, Ruz et al [15] concluded that a supplement of 9.5 mg Zn daily after RYGB would not be sufficient to prevent an impairment of Zn status. Authors suggested that there was hence the justification for use of a higher dose of supplement probably in the range of 40 60 mg/ day.…”

“…Up to half [9][10][11][12][13] of bariatric surgery patients are deficient in Zn preoperatively and RYGB can further exacerbate it [4,9,12] through probably both reduced intake [15][16][17][18] and reduced absorption [15,19] as Zn is predominantly absorbed in the duodenum and the proximal jejunum.…”