Micronutrient intake and biochemistry in adolescents adherent or nonadherent to supplements 5 years after Roux-en-Y gastric bypass surgery.

Background: Roux-en-Y gastric bypass (RYGB) is an effective obesity treatment in adults and has become established in adolescents. Lower adherence to supplementation in adolescents confers a risk for long-term nutritional deficiencies.

Objectives: To assess adherence to supplementation, micronutrient intake, and biochemistry in adolescents through 5 years after RYGB.

Setting: University hospitals, multicenter study, Sweden.

Methods: Micronutrient intake and adherence to supplementation were assessed by diet history interviews and biochemistry preoperatively, 1, 2, and 5 years after RYGB in 85 adolescents (67% females), aged 16.5 years (± 1.2) with a body mass index of 45.5 kg/m (± 6.0). Adherence was defined as taking prescribed supplements ≥3 times a week. Micronutrient intake and biochemistry were compared with matched controls at 5 years.

Results: Over 75% completed the dietary assessments across 5 years after RYGB. Adherence ranged between 44-61% through 5 years. At 5 years, ferritin and hemoglobin decreased (P < .04) and 61% had iron deficiency (P ≤ .001). Among females with iron deficiency, most did not adhere to supplementation (P = .005), and 59% of these had anemia (P < .001). Vitamin D insufficiency continued after surgery and 80% of participants who did not adhere to supplementation had insufficiency (P = .002). Adolescents not adhering had lower levels of vitamin D, B, and ferritin (females) compared with both adhering adolescents and the control group (all P < .04).

Conclusions: Half of adolescents after RYGB reported sufficient long-term adherence to supplementation. Adhering to supplements and reporting a higher micronutrient intake were associated with more favorable biochemistry. Results support the recommendations for monitoring micronutrient intake and biochemistry in all patients who have undergone RYGB surgery, and the recommendation of higher preventive supplementation of vitamin D and iron in both sexes. As hypothesized, adolescents not adhering had a higher prevalence of long-term micronutrient deficiencies.