Women with and without obesity have a similar distribution of vitamin D in their adipose tissue, as well as a similar correlation between serum 25-hydroxyvitamin D and total vitamin D in both subcutaneous and omental fat compartments, study data show.
In a single-center study, Angela Carrelli, MD, of the division of endocrinology, department of medicine at Columbia University College of Physicians and Surgeons in New York, and colleagues analyzed data from 21 women with obesity referred for bariatric surgery (BMI > 35 kg/m²; mean BMI, 44 kg/m²; mean age, 42 years) and 15 normal-weight women who served as controls (BMI < 25 kg/m²; mean BMI, 23 kg/m²; mean age, 41 years) undergoing laparoscopic abdominal surgery for benign gynecologic indications. Researchers measured total fat mass, lean mass and percent fat mass via DXA and serum 25-(OH)D concentrations; biopsies of subcutaneous and omental fat were obtained intraoperatively to assess distribution of vitamins D2 and D3.
Researchers observed no between-group differences in serum 25-(OH)D, likely reflecting the 71% of women in the obesity group using supplemental vitamin D.
Researchers found no between-group differences in total vitamin D concentrations in either the subcutaneous adipose tissue (34.2 ng/g vs. 25.7 ng/g) or omental adipose tissue (50.6 ng/g vs. 29.7 ng/g). The concentration of vitamin D in subcutaneous tissue was correlated with serum 25-(OH)D levels in woman with obesity (r = 0.66; P < .01) and controls (r = 0.64; P < .03), as was the concentration of vitamin D in omental tissue (r = 0.61; P < .01 and r = 0.68; P < .01, respectively).
When calculating body composition measurements and fat biopsy data, researchers found that total body vitamin D stores were greater in women with obesity vs. controls (2.29 mg vs. 0.44 mg).
“The data extend the limited prior information on vitamin D in the adipose tissue of the obese, confirming with increased accuracy their substantially greater total body stores of vitamin D, and demonstrating that concentrations of vitamin D varied according to compartment,” the researchers wrote. “Specifically, vitamin D was higher in omental as compared to subcutaneous fat. The findings suggest that vitamin D metabolism has more similarities than differences across the weight spectrum.” – by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.