Background

Patients with morbid obesity have a low blood 25(OH)D level with a high frequency of Vitamin D (VD) deficiency (less than 20ng/mL of 25(OH)D), but the actual condition remains unknown in Japan because the measurement of a blood 25(OH)D level was not covered by national health insurance until recent years. Furthermore, VD profile after bariatric surgery (BS), adequate VD replacement has not been clarified yet. The study aims to clarify the actual condition of VD profile before/after bariatric surgery for Japanese patients with morbid obesity and also investigated the appropriate VD replacement after BS.

Methods

For 39 consecutive Japanese patients with morbid obesity (BMI>35kg/m2) treated with BS, the study retrospectively examined the results based on nutrient intake including VD as well as a blood 25(OH)D level for 1 year before/after BS (22 cases). Moreover, in 5 cases with VD deficiency after BS, the study investigated change in a blood 25(OH)D level for those patients with VD supplement (2,000IU/day) for average 3 months in addition to ordinary dietary therapy.

Results

Although average VD intake (292IU/day) before BS exceeded the intake (220IU/day) recommended by the Ministry of Health, Labor and Welfare of Japan, a blood 25(OH)D level indicated lower as average 13.6ng/ml and 87% of the patients were included in the criteria of VD deficiency. Body weight was decreased (-28kg), glycolipid metabolism index was significantly improved within 1 year after BS while there was no change in 25(OH)D level and the frequency of VD deficient patients (14.5→14.6ng/ml, 87%). In 5 cases with VD deficiency after BS, additional intake of VD supplement increased a blood 25(OH)D level in all cases, but the increase level was small in bypass surgeries compared to sleeve surgeries.

Conclusions

VD deficiency in Japanese patients with morbid obesity demonstrates a high frequency and a blood 25(OH)D level does not increase after BS. Yet, it is necessary to consider appropriate VD replacement before/after the BS.