Malnutrition in Bariatric Surgery Candidates: Multiple Micronutrient Deficiencies Prior to Surgery

Over 78 million American adults have obesity. Bariatric surgery is the leading means of durable weight loss. Nutritional deficiencies are commonly treated post-operatively but are often undiagnosed pre-operatively. Malnutrition is correlated with adverse surgical outcomes.

The aim of this study is to assess pre-operative nutritional status in our bariatric surgery candidates in a cross-sectional study.

We recruited 58 bariatric candidates approved to undergo the Roux-en Y gastric bypass. Nutritional status was determined for vitamins A, B₁₂, D, E-α, and E-β/γ as well as thiamine, folate, and iron. We used clinical as well as frank deficiency cut-offs based on the Institute of Medicine and the World Health Organization guidelines.

This cohort was largely female (77.6 %) and white (63.8 %). Median age was 42.2 years. Median body mass index (BMI) was 46.3 kg/m². Multiple comorbidities (MCM) were present in 41.4 %, 54.0 % hypertension, 42.0 % diabetic, 34.0 % sleep apnea. Men had more comorbidities, 69.2 % with MCM. Folate and iron saturation varied significantly by sex. Vitamins A, D, E-α, and thiamine significantly varied by race. Vitamin D negatively correlated with BMI (p = 0.003) and age (p = 0.030). Vitamin A negatively correlated with age (p = 0.001) and number of comorbidities (p = 0.003). These pre-operative bariatric candidates had significant malnutrition, particularly in vitamin D (92.9 %) and iron (36.2 to 56.9 %). Multiple micronutrient deficiency (MMND) was more common in blacks (50.0 versus 39.7 % overall). Number of comorbidities did not correlate with MMND.

Malnutrition in one or multiple micronutrients is pervasive in this pre-operative bariatric cohort. The effect of pre-operative supplementation, especially vitamin D and iron, should be explored.