Micronutrient Status in Patients with Severe Obesity Before and After Laparoscopic Sleeve Gastrectomy

Background: Micronutrient deficiencies (MNDs) are commonly reported after bariatric and metabolic surgery, including laparoscopic sleeve gastrectomy (LSG). Nevertheless, the micronutrient status changes over time and the influence of sex or initial body mass index (BMI) on these changes are less explored. This study aims to investigate the changes in micronutrient levels at 6 and 12 months after LSG and the potential influence of sex or baseline BMI (≥40 kg/m²) on these changes in patients submitted to LSG. Additionally, the frequency of MNDs before and at 12 months after the procedure was investigated. Materials and methods: Fifty patients with obesity underwent LSG and were assessed anthropometrically and nutritionally at baseline and at 6 and 12 months, respectively, after LSG. The changes in micronutrients levels over time were tested by a linear mixed model. Results: Vitamin B₁₂ and vitamin D [25(OH)D] did not change significantly, while iron (p < 0.001), calcium (p = 0.01), and parathormone (p < 0.001) differed significantly from baseline to 12 months after LSG. Ferritin significantly decreased from baseline to 6 months and 12 months after LSG (LS-means, 95% CI: 202 [163, 240] vs. 160 [130, 191] vs. 150 [115, 185]). Sex or initial severe obesity (BMI ≥ 40 kg/m²) exhibited significant modifying effects for 25(OH)D and calcium, respectively. The 25(OH)D levels increased significantly in men, but not in women, while the calcium plasma concentration changed significantly only in patients with initial severe obesity. No significant changes over time were found for MNDs' frequency (p > 0.05). The most consistent deficiency frequency was observed for 25(OH)D both before and after LSG. Conclusions: Overall, our findings revealed changes in micronutrient status across the follow-up period, except for vitamin B₁₂. Variations in 25(OH)D levels were reported exclusively in men, suggesting that they depend on sex. The calcium plasma concentration showed significant changes exclusively in patients with BMI ≥ 40 kg/m². MNDs' frequency was not significantly altered during the study follow-up. Our results reinforce the need for developing national dietary guidelines tailored for Romanian patients following LSG.