Evaluation of vitamin B12 levels among severe obese and obese adolescents

Obesity, whose prevalence is increasing globally, is malnutrition that causes micro/macronutrients and vitamin deficiencies in adolescents. Vitamin B12 plays a prominent role in the body systems such as remethylation, deoxidation, and DNA synthesis. We aimed to examine the relationship between severe obese/obese adolescents and vitamin B12 levels in this study. This study was conducted as a case–control study consisting of 44 obese and 40 healthy control adolescents aged 11–17 years. Obesity was diagnosed using body mass index (BMI) charts defined by the World Health Organization according to age and gender. Vitamin B12 deficiency was found to be 34.1% in the patient obesity group, while it was 12.5% in the control group (p = 0.02). Homeostatic Model Assessment for Insulin Resistance levels were found to be 3.09 (1.9–5.29) higher in the severely obese group (p < 0.001). The median level of vitamin B12 in the obese group was 173 (122.5–220.7) in the severe obese group, 197 (146.5–302.7) in the obese group, and 252.5 (192.8–302) in the control group (p = 0.021). We found that obesity has a 1.6-fold decreasing effect on vitamin B12 levels. This study shows the clinician the importance of monitoring BMI and vitamin B12 levels in obese adolescents, given the effects of vitamin B12 on neuronal migration, metabolic reactions, and many systems in the body. Further researches are needed to investigate the pathophysiology and effect of low vitamin B12 levels in obese adolescents.