Rising Serum 25-Hydroxy-Vitamin D Levels after Weight Loss in Obese Women Correlate with Improvement in Insulin Resistance

Tzotzas, Themistoklis; Papadopoulou, Fotini; Tziomalos, Kostantinos; Karras, Spyridon Ν.; Gastaris, Kostantinos; Perros, Petros; Krassas, Gerasimos E

doi:10.1210/jc.2010-0757

Cited by 143 publications

(103 citation statements)

References 41 publications

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“…Similar findings were reported by others after diet and/or exerciseinduced weight loss. 9,10,12 These findings are in agreement with the hypothesis that VD is being stored in the AT 24,26 and confirm previous data on how plasma 25OHD depends on the volume of distribution. 23 The increase in 25OHD fits very well with the observed increased expression of the degrading enzyme, the 24-hydroxylase CYP24A1, as CYP24A1 expression is induced by 1,25-OH 2 D. 36,37 As CYP24A1 degrades both 25OHD and 1,25(OH) 2 D, these findings suggest a higher turnover of both 25OHD and 1,25(OH) 2 D following weight loss.…”

Section: Discussionsupporting

confidence: 91%

“…However, results are inconsistent. After diet-and exercise-induced weight loss, both increased [9][10][11] and unaltered 12,13 circulating levels of 25OHD have been reported. 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.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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OBJECTIVE: Low vitamin D (VD) levels are common in obesity. We hypothesized that this may be due to metabolism of VD in adipose tissue (AT). Thus, we studied (1) whether the VD-metabolizing enzymes were expressed differently in AT of lean and obese individuals and in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and (2) whether their expression was influenced by weight loss. METHODS: Samples of SAT and VAT were analyzed for expression of the vitamin-D-25-hydroxylases CYP2R1, CYP2J2, CYP27A1 and CYP3A4, the 25-vitamin-D-1a-hydroxylase CYP27B1, the catabolic vitamin-D-24-hydroxylase CYP24A1, and the vitamin D receptor, using reverse transcriptase-PCR. Moreover, plasma 25-hydroxy-vitamin D (25OHD) level was measured and related to the expression of these enzymes. Samples of SAT and VAT from 20 lean women and 20 obese women, and samples of SAT from 17 obese subjects before and after a 10% weight loss were analyzed. RESULTS: A plasma 25OHD level o50 nmol l À 1 was highly prevalent in both lean (45%) and obese (90%) women (Po0.01). Plasma 25OHD increased by 27% after weight loss in the obese individuals (Po0.05). Expression levels of the 25-hydroxylase CYP2J2 and the 1a-hydroxylase CYP27B1 were decreased by 71% (Po0.0001) and 49% (Po0.05), respectively, in SAT of the obese. CYP24A1 did not differ between lean and obese women, but the expression was increased by 79% (Po0.05) after weight loss. CONCLUSION: Obesity is characterized by a decreased expression of the 25-hydroxylase CYP2J2 and the 1a-hydroxylase CYP27B1 in SAT, whereas the catabolic CYP24A1 does not differ between lean and obese women. However, the expression of CYP24A1 is increased after weight loss. Accordingly, AT has the capacity to metabolize VD locally, and this can be dynamically altered during obesity and weight loss. INTRODUCTIONLow levels of circulating 25-hydroxy-vitamin D (25OHD) are associated with increased fat mass and body mass index, 1-5 but the underlying mechanism for this association is not fully elucidated. 6 Vitamin D (VD) is stored in adipose tissue (AT), and release of VD from AT is proposed to serve as an endogenous source of VD during the winter, when cutaneous production is low or absent in several parts of the world. 7 As low circulating levels of 25OHD are common in association with the obese state, 8 several studies have examined the effect of weight loss on circulating levels of 25OHD. However, results are inconsistent. After diet-and exercise-induced weight loss, both increased 9-11 and unaltered 12,13 circulating levels of 25OHD have been reported. Likewise, after major weight loss by bariatric surgery, both temporary 14-16 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 ...

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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“…The demonstrated inverse relationship between BMI and vitamin D status has been established in earlier reports (48,49). It has been shown that in obese individuals a higher proportion of vitamin D, which is fat soluble, is sequestered in adipose tissue and thereby the bioavailability of vitamin D is low.…”

Section: Discussionmentioning

confidence: 67%

The role of vitamin D in metabolic disturbances in polycystic ovary syndrome: a systematic review

Krul-Poel

Snackey

Louwers

et al. 2013

European Journal of Endocrinology

115

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Context: Metabolic disturbances, in particular, insulin resistance (IR) and dyslipidemia, are common in women suffering from polycystic ovary syndrome (PCOS). Evidence is accumulating that vitamin D status may contribute to the development of metabolic disturbances in PCOS. Objective: The aim of this study was to carry out a systematic review addressing the association between vitamin D status, vitamin D receptor polymorphisms, and/or polymorphisms related to vitamin D metabolism and metabolic disturbances in women with PCOS. Design and methods: A systematic search of electronic databases was carried out up to January 2013 for observational studies and clinical trials in women suffering from PCOS with outcome measures that were related to vitamin D status. We conducted univariate and multivariate regression analyses of the weighted means to gain insights into the association between vitamin D, BMI, and IR based on existing literature. Results: We found 29 eligible trials with inconsistency in their results. One well-designed randomized controlled trial has been carried out until now. Univariate regression analyses of the weighted means revealed vitamin D to be a significant and independent predictor of IR in both PCOS and control women. The significance disappeared after adjustment for BMI in PCOS women. Conclusions: Current evidence suggests an inverse association between vitamin D status and metabolic disturbances in PCOS. Owing to the heterogeneity of the studies, it is hard to draw a definite conclusion. The causal relationship between vitamin D status and metabolic disturbances in PCOS remains to be determined in well-designed placebo-controlled randomized clinical trials.

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“…The observation that obesity is associated with below-normal serum 25-hydroxyvitamin D concentrations and/or overt deficiency is not new; however, as obesity prevalence has grown, so have the number of reports in the literature regarding this phenomenon. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Some of the most recent information about low vitamin D status and obesity comes from studies in bariatric surgery patients, reporting low preoperative circulating levels of 25-hydroxyvitamin D. [21][22][23][24][25][26][27][33][34][35][36][37][38] In fact, a recent systematic review of 14 studies with about 1500 patients undergoing bariatric surgical procedures confirmed that obese individuals have serum 25-hydroxyvitamin D levels below 80 nmol l À1 preoperatively. 39 Other investigators have reported that body mass index (BMI) 25,26,[40][41][42][43][44][45][46] and body fat 20,45,…”

Section: Methodsmentioning

confidence: 99%

“…They reported an initial increase (at 6 weeks and 6 months after surgery) in serum 25-hydroxyvitamin D concentrations, which declined toward baseline by 1 year after RYGB. Tzotzas et al 66 reported that serum 25-hydroxyvitamin D concentrations increased with nonbariatric surgery-induced weight loss. Taken together, these studies provide some level of support for the notion that adipose tissue could be sequestering vitamin D, and that, at least during the early phases of weight loss, it is possible that vitamin D may be released into circulation.…”

Section: Methodsmentioning

confidence: 99%

The link between obesity and low circulating 25-hydroxyvitamin D concentrations: considerations and implications

et al. 2011

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Obesity and vitamin D deficiency have both been recognized as major public health issues worldwide, and there is growing evidence that they are related, although the cause-effect relationship remains unclear. Could obesity be contributing to low circulating 25-hydroxyvitamin D concentrations? Alternatively, could low vitamin D status predispose to obesity? In this review, the relationship between low circulating 25-hydroxyvitamin D and obesity, and possible underlying reasons from both perspectives, is presented. One potential mechanism by which obesity could contribute to low serum 25-hydroxyvitamin D is adipose sequestration of vitamin D. On the other hand, adipose tissue has both the vitamin D receptor and the ability to synthesize 1,25-dihydroxyvitamin D, and there is evidence that vitamin D may regulate adipose tissue mass, differentiation and metabolism in ways that might contribute to obesity. Of particular interest, vitamin D deficiency is common both before and after bariatric surgery, and is often difficult to treat, particularly with the more malabsorptive procedures. Additional research is needed to elucidate the complex and multifaceted factors underlying the association between low circulating 25-hydroxyvitamin D and obesity, and to identify optimal treatment approaches in obese individuals and in bariatric surgical patients both before and after surgery.

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Rising Serum 25-Hydroxy-Vitamin D Levels after Weight Loss in Obese Women Correlate with Improvement in Insulin Resistance

Abstract: Blood 25OHD levels were low in obese women and correlated inversely with severity measures of obesity. Weight loss of 10% after low-calorie diet increased 25OHD levels, and this increase was mainly associated with improvement of insulin resistance.

Cited by 143 publications

References 41 publications

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

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

The role of vitamin D in metabolic disturbances in polycystic ovary syndrome: a systematic review

The link between obesity and low circulating 25-hydroxyvitamin D concentrations: considerations and implications

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