Pre-operative micronutrient deficiencies in patients with severe obesity candidates for bariatric surgery

In patients with obesity, micronutrient deficiencies have been reported both before and after bariatric surgery (BS). Obesity is a chronic pro-inflammatory status, and inflammation increases the risk of micronutrient malnutrition. Our objective was to assess in pre-BS patients the prevalence of micronutrient deficiencies and their correlation with blood values of C-reactive protein (CRP).

Anthropometric data, instrumental examinations, and blood variables were centrally measured in the first 200 patients undergoing a pre-BS evaluation at the "Città della Salute e della Scienza" Hospital of Torino, starting from January 2018.

At least one micronutrient deficiency was present in 85.5% of pre-BS patients. Vitamin D deficiency was the most prevalent (74.5%), followed by folate (33.5%), iron (32%), calcium (13%), vitamin B12 (10%), and albumin (5.5%) deficiency. CRP values were high (> 5 mg/L) in 65% of the patients. These individuals showed increased rate of iron, folate, vitamin B12 deficiency, and a higher number of micronutrient deficiencies. In a multiple logistic regression model, increased CRP levels were significantly associated with deficiencies of vitamin B12 (OR = 5.84; 95% CI 1.25-27.2; p = 0.024), folate (OR = 4.02; 1.87-8.66; p < 0.001), and with the presence of ≥ 2 micronutrient deficiencies (OR = 2.31; 1.21-4.42; p = 0.01).

Micronutrient deficiencies are common in patients with severe obesity undergoing BS, especially when inflammation is present. In the presence of increased CRP values before surgery, it might be advisable to search for possible multiple micronutrient deficiencies.