Vitamin status after gastric bypass and lifestyle intervention: a comparative prospective study

Bariatric surgery can lead to vitamin deficiencies. We aimed to assess the changes in blood vitamin concentrations in patients who were taking predefined supplements after gastric bypass surgery.

A total of 29 patients underwent gastric bypass and 24 unmatched controls underwent lifestyle intervention in a prospective, nonrandomized trial. The patients in the surgical group received multivitamin, iron, calcium, vitamin D, and vitamin B(12) supplements. No supplements were prescribed to the lifestyle group. The median body mass index decreased from 46 to 32 kg/m(2) after surgery and from 40 to 39 kg/m(2) after lifestyle intervention.

Of the 53 included patients, 50 completed the 1-year follow-up examination (94%). Compared with the lifestyle patients, the surgical patients had increased vitamin B(6), folic acid, vitamin B(12), and lipid-adjusted vitamin E (P <.02 for each) concentrations but decreased vitamin A concentrations (P <.01) during follow-up. No significant difference between the 2 groups was found for vitamin B(1), vitamin C, or 25-hydroxyvitamin D. Most surgical patients reported taking their supplements.

Gastric bypass patients adhering to a set of dietary supplements had mostly stable or increased vitamin concentrations compared with both their baseline values and the changes in a nonsurgical control group.