The Effect of Ferritin on Weight Loss in Patients Undergoing Bariatric Surgery: A Prospective Cohort Study

Weight loss may cause nutrient deficiencies that hinder further weight loss. This study aimed to assess serum ferritin, folate, and vitamin B12 levels and examine their roles in weight loss after bariatric surgery (BS).

In 135 obese patients, serum ferritin, folate, and vitamin B12 levels were measured from baseline to 12 months post-BS. Weight loss was measured by percentage of total weight loss (%TWL) and excess weight loss (%EWL) using linear regression.

The median %TWL and %EWL were 30.66 (26.63-35.30) and 88.44 (76.12-108.17), respectively. Ferritin, folate, and vitamin B12 deficiencies were recorded in 6.67%, 0.74%, and 8.15% at baseline and 27.61%, 5.19%, and 18.52% at 12 months post-BS, respectively. Serum ferritin at 12 months post-BS was positively correlated with %EWL (β 0.07, 95% CI 0.00-0.14, p = 0.041). The difference in ferritin levels (baseline subtracted from 12 months post-BS) was negatively correlated with %TWL (β -0.02, 95% CI -0.04 to -0.01, p = 0.010) and %EWL (β -0.11, 95% CI -0.18 to -0.05, p < 0.001).

Serum ferritin levels were positively associated with weight loss after BS. Monitoring and appropriate iron supplementation are recommended in patients undergoing BS.