Fat-soluble vitamin deficiencies after bariatric surgery could be misleading if they are not appropriately adjusted

To evaluate the differences in frequency of fat-soluble vitamin deficiencies if we adjust their levels by its main carriers in plasma in patients undergoing Biliopancreatic diversion (BPD) and Roux-en-Y gastric bypass (RYGB).

We recruited 178 patients who underwent RYGB (n = 116 patients) and BPD (n = 62 patients) in a single centre. Basal data information and one-year after surgery included: anthropometric measurements, fat-soluble vitamins A, E and D, retinol binding protein (RBP) and total cholesterol as carriers of vitamin A and E respectively. Continuous data were compared using T-Student and proportions using chisquare test.

There was a vitamin D deficiency of 96% of all patients, 10% vitamin A deficiency and 1.2% vitamin E deficiency prior to surgery. One year after surgery, 33% of patients were vitamin A deficient but the frequency reduced to 19% when we adjusted by RBP. We found a vitamin E deficiency frequency of 0% in RYGB and 4.8% in DBP one year after surgery. However, when we adjusted the serum levels to total cholesterol, we found an increased frequency of 8.7% in RYGB group for vitamin E deficiency and 21.4% in DBP (p = 0.04).

We have found a different frequency of deficit for fat-soluble vitamin both in BPD and RYGB once we have adjusted for its main carriers. This is clinically relevant to prevent from overexposure and toxicity. We suggest that carrier molecules should be routinely requested when we assess fat-soluble vitamin status in patients who undergo malabsorptive procedures.