INTRODUCTION: Roux-en-Y gastric bypass (RYGB) induces substantial weight loss and changes in glucose homeostasis, partly through alterations in gastrointestinal anatomy and nutrient absorption. Sodium-glucose co-transporters-1 (SGLT-1) facilitate intestinal glucose absorption, a process that may be compromised post-RYGB. Animal studies suggest that sodium supplementation to a meal may enhance SGLT-1 activity post-RYGB. In this study, we investigated whether adding sodium chloride (NaCl) to a carbohydrate-rich meal affects glucose homeostasis in people after RYGB.
METHODS: In this open-label, randomized, crossover study, eleven adults without diabetes post-RYGB (mean age 57.3 ± 11.3 years, BMI 35.1 ± 7.5 kg/m2, 64% female) underwent two mixed meal tolerance tests (MMTT), on separate days, either with or without 2 g of additional NaCl (785 mg sodium). The primary outcome was the difference in nadir postprandial plasma glucose between conditions. Secondary outcomes included differences in area under the curve (AUC), fasting and peak plasma glucose, insulin, c-peptide and glucagon-like peptide-1 (GLP-1) concentrations. 0 - 180'
RESULTS: The addition of 2 g NaCl did not alter nadir plasma glucose (3.7 mmol/L with NaCl vs 3.5 mmol/L without NaCl, 95% CI: -0.50 to 0.30, p = 0.55), fasting glucose or AUCglucose. However, peak plasma glucose was lower with NaCl (7.8 vs 8.3 mmol/L, 95% CI: -0.88 to -0.08, p = 0.02). No differences were observed in AUC, fasting and peak insulin, c-peptide and GLP-1 concentrations between the conditions. 0 - 180' 0 - 180'
CONCLUSIONS: In individuals post-RYGB without diabetes, sodium supplementation during a carbohydrate-rich meal did not substantially affect glucose homeostasis, although it appeared to reduce peak postprandial plasma glucose. Further studies are warranted to explore the clinical relevance of this effect.
