Impact of Bariatric Surgery on Micronutrient Levels: Evidence from NHANES 2015-2018, a Cross-Sectional Study

The 2022 updates from the American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) have revised the indications for metabolic and bariatric surgery (MBS). This study investigated the association between a history of MBS and micronutrient status in a nationally representative U.S. adult population.

The study included 2,970 adults aged ≥ 18 years from the National Health and Nutrition Examination Survey (2015-2018). Participants were categorized into three groups: (1) individuals with a BMI within the normal weight range (18.5-24.9 kg/m²); (2) individuals with a history of MBS; and (3) individuals who met the eligibility criteria for MBS but had not undergone the procedure. Weighted logistic regression models were used to compare between-group differences in the prevalence of micronutrient abnormalities.

Compared to the individuals with normal weight group, individuals eligible for MBS but without a history of surgery exhibited an increased likelihood of hyperferritinemia (OR, 1.779; 95% CI: 1.168-2.709), high transferrin receptor levels (OR, 2.145; 95% CI: 1.175-3.917), hypocalcemia (OR, 3.415; 95% CI: 1.306-8.929), and vitamin D deficiency (OR, 2.126; 95% CI: 1.522-2.969). In contrast, no statistically significant differences in the prevalence of these conditions were observed between the group with a history of MBS and the individuals with normal weight group.

In this cross-sectional analysis, individuals eligible for MBS who had not undergone surgery showed a higher prevalence of several micronutrient abnormalities compared to individuals with normal weight. This pattern was not observed in individuals with a history of MBS, suggesting that postoperative management, including micronutrient supplementation, may mitigate these deficiencies. However, these findings should be interpreted with caution due to the study's limitations.