Nutrient Deficiency After Bariatric Surgery in Adolescents: A Systematic Review and Meta-Analysis.

Objective: This systematic review and meta-analysis study aimed to estimate changes in blood nutrient concentrations and nutrient deficiencies in adolescents following bariatric surgery.

Methods: We searched PubMed, Scopus, and the Web of Science to find studies published between January 2000 and August 2023. Observational studies reporting the mean blood concentration of nutrients before and after bariatric surgery or the proportion of nutrient deficiencies after the surgery in healthy adolescents were selected.

Results: Fifteen studies were included. Gastric bypass and sleeve gastrostomy were the most common types of surgery. Vitamin D, iron, or ferritin, vitamin B12, calcium, and folic acid were the most studied nutrients, respectively. Other nutrients examined in the studies included zinc, phosphorus, and albumin. The serum ferritin increased by 21 mcg/L (95% CI = 10.0, 32.0 mcg/L) after the surgery, but there were no significant alterations in other nutrients. The postoperative prevalence of low albumin, ferritin, vitamin D, and vitamin B12 levels was 10%, 49%, 41%, and 20%, respectively. Also, 23% had an iron deficiency, and 10% had a calcium deficiency after bariatric surgery.

Conclusions: The serum ferritin level increased following bariatric surgery in adolescents. Vitamin D and ferritin deficiencies were estimated to be present in more than one-third of adolescents after the surgery.