Background: Bariatric surgery is considered the most effective treatment for obesity class II and III. However, postoperative side effects may occur, such as nutritional deficiencies resulting from reduced gastric capacity and alterations in nutrient absorption along the gastrointestinal tract.
Methods: A total of 170 patients (136 women and 34 men) submitted to Roux-en-Y gastric bypass (RYGB) between 2000 and 2005 were retrospectively assessed. Anthropometric and laboratory data were evaluated and the use of vitamin and mineral supplements, before and 1, 6, 12, 24, and 36 months following surgery, was assessed, as well.
Results: Mean excess weight loss at 24 and 36 months was 81.5 ± 19.2 and 78.5 ± 20.8 %, respectively. Anemia was present in 6.5 % of subjects prior to the surgery and increased to 33.5 % at 36 months. The levels of total cholesterol, low-density lipoprotein cholesterol, triglycerides, and glycemia were reduced, while high-density lipoprotein cholesterol was increased. Albumin and vitamin B12 levels showed no significant differences at the end of the study compared to the preoperative evaluation. Folic acid levels increased significantly during the follow-up. Almost 6 % of the patients had used standard vitamin and mineral supplements in the preoperative period and 72.4, 85.3, 74.7, 77.1, and 72.4 % at 1, 6, 12, 24, and 36 months following RYGB, respectively.
Conclusions: Bariatric surgery is an effective treatment for long-term weight loss. However, nutritional deficiency is one of its side effects and should be properly diagnosed and handled, aimed at improving the patient's quality of life and preventing severe complications.