Protein and amino acid status before and after bariatric surgery: a 12-month follow-up study.

Background: Patients with obesity submitted to bariatric surgery present altered ingestion of macronutrient and micronutrient levels and nutrients deficiency. The objective of this study was to evaluate the protein and amino acid nutritional status of obese adults before and after bariatric surgery, with emphasis on plasma free amino acids.

Methods: Thirty obese women were submitted to Roux-en-Y gastric shunt (bariatric surgery). Food and protein intake, anthropometric and bioimpedance data (body composition analysis), and serum total protein, albumin, and plasma amino acids levels were collected before the surgery (preoperative) and 3, 6, and 12 months after the surgical procedure.

Results: The mean protein intake was 47±2 g/day. The total weight loss during the study period was 39±8 kg; the fat-free mass decreased 7±5 kg. The amino acid profile showed increased concentrations of most amino acids 3 months after surgery; at 6 months, glutamic acid, serine, arginine, alanine, methionine, valine, phenylalanine, isoleucine, and tyrosine concentrations decreased. The total protein and albumin concentrations dropped along the 12-month follow-up.

Conclusion: The amino acid profile changes after RYGB are evidence that total protein and albumin levels may not be good indicators of protein profile after the surgery.