Vitamin D in Adipose Tissue and Serum 25‐Hydroxyvitamin D After Roux‐en‐Y Gastric Bypass

Abstract

articles Bariatric surgery vitamin D reserve as body fat mass declines after surgery. The purpose of this study is to determine the amount of vitamin D in adipose tissue of severely obese patients at the time of RYGB, and to describe changes in serum 25(OH)D during a follow-up period of up to 1 year as it relates to the subject's initial fat vitamin D content and amount of fat mobilization as determined by weight loss. Methods and ProceduresThe study was reviewed and approved by the institutional review board of Boston University Medical Center, and written informed consent was obtained from each subject. Severely obese patients from the Nutrition and Weight Management Center at Boston Medical Center in Boston, MA (latitude 42° 19' N) who were already scheduled to undergo RYGB surgery, as part of their treatment, were invited to participate in this prospective, observational study. Patients whose plan of obesity treatment did not include surgery were not invited. Subjects were not compensated for participating in this study. Exclusion criteria included age of less than 18 years old, pregnancy, liver disease, and kidney disease.At the preoperative visit, patients were consented and demographic and medical history was obtained. Subjects were asked to provide blood which was used to determine 25(OH)D level. All surgeries were performed by a single surgeon at Boston University Medical Center from years 2003 to 2007. RYGB was performed with approximate roux limb length of 100 cm, gastric pouch size of 30 ml, and gastrojejunostomy anastomosis size of 10-11 mm. Discarded abdominal subcutaneous, omental, and mesenteric adipose tissue was obtained at the time of surgery, and was flash frozen using liquid nitrogen and stored at −80 °C for determination of vitamin D concentration.Subjects were scheduled for study visits at 3, 6, 9, and 12 months after surgery and were contacted to reschedule if they missed an appointment. At each visit, patients were weighed, BMI was calculated, and blood was drawn and used to determine serum 25(OH)D. Amount of vitamin D intake was assessed at each visit by patient self-report and their medical and prescription records. Subjects who were found to be vitamin D deficient were treated at the discretion of the physician, either before or during the study period. Treatment regimen used at this institution was 50,000 IU of vitamin D 2 , taken continuously at a weekly interval (4).

Expression of vitamin D-metabolizing enzymes in human adipose tissue—the effect of obesity and diet-induced weight loss

“…Likewise, after major weight loss by bariatric surgery, both temporary [14][15][16] and long-term increases [16][17][18] in circulating levels of 25OHD have been reported, along with reports of no changes one year after surgery. 13,19 Taken together, these findings indicate that body weight is an important factor for circulating 25OHD levels. Several other explanations for the low levels of 25OHD in obesity have been proposed: a decreased exposure to sun light, 20 or a decreased hepatic 25-hydroxylation of VD in obesity inhibited by elevated levels of 1,25-OH 2 D and PTH 21 could contribute to the decreased levels of 25OHD in obesity.…”

“…4,5,19,[48][49][50][51][52] The high prevalence of low VD levels in obesity is proposed to be due to volumetric dilution in obesity, as the volume of distribution of VD increases with increased body weight. 23 Our study aimed to elucidate whether low plasma 25OHD levels in obesity could be further explained by an altered VD metabolism.…”

Vitamin D modulates adipose tissue biology: possible consequences for obesity?

“…Alternatively, VD 3 is produced endogenously in the skin after UVB irradiation from the precursor 7-dehydrocholesterol to give pre-VD 3 , which is further isomerised to VD 3 before being released into the circulation (4) . Classical estimates have assigned a majority (70-90 %) of VD supply to dermal synthesis, but a recent paper revised this figure down to just 10-25 % of VD supply (5) and posited that dietary intake of 25-hydroxy-vitamin D (25(OH)D) is a significant contributor to total VD input.Adipose tissue is a major storage site for vitamin D Despite limited data, it is widely accepted that adipose tissue is a reservoir for VD in human subjects and rats (6)(7)(8)(9)(10) . Interestingly, visceral fat was found to contain 20 % more VD than subcutaneous fat (11) .…”

“…Adipose tissue is a major storage site for vitamin D Despite limited data, it is widely accepted that adipose tissue is a reservoir for VD in human subjects and rats (6)(7)(8)(9)(10) . Interestingly, visceral fat was found to contain 20 % more VD than subcutaneous fat (11) .…”

Association of the Metabolic Syndrome and Vitamin D Receptor Gene Polymorphisms: A Cross Sectional Study

“…Karatas et al (2013) (Wortsman et al, 2000;Blum et al, 2008). Contradictory opinion was proposed by Pramyothin et al (2011) who assessed for the vitamin D levels in the subcutaneous abdominal fat taken from 17 patients undertaking gastric bypass surgery. In addition to measuring Vitamin D at surgery, it was also monitored over a 12-month follow-up period.…”