title: Influence of vitamin D and estrogen receptor gene polymorphisms on calcium absorption: BsmI predicts a greater decrease during energy restriction.
abstract: Low calcium absorption is associated with low bone mass and fracture. In this study, we use gold standard methods of fractional calcium absorption (FCA) to determine whether polymorphisms of intestinal receptors, vitamin D receptor (VDR) and estrogen receptor α (ESR1), influence the response to energy restriction. Fractional calcium absorption was measured using dual stable isotopes ((42)Ca and (43)Ca) in women given adequate calcium and vitamin D and examined at baseline and after 6 weeks of energy restriction or no intervention. After genotyping, the relationship between VDR and ESR1 genotypes/haplotypes and FCA response was assessed using several genetic models. One-hundred and sixty-eight women (53 ± 11 years of age) were included in this analysis. The ESR1 polymorphisms, PvuII and XbaI and VDR polymorphisms (TaqI, ApaI) did not significantly influence FCA. The BB genotype of the VDR polymorphism, BsmI, was associated with a greater decrease in FCA than the Bb/bb genotype. Multiple linear regression showed that the BsmI polymorphism or the VDR haplotype, BAt, in addition to changes in weight and vitamin D intake explained ~16% of the variation in changes in FCA. In conclusion, the reduction in calcium absorption due to energy restriction is greatest for those with the BB genotype. Previous candidate gene studies show that VDR polymorphisms are associated with higher risk for osteoporosis, and the current study supports the notion that the BsmI polymorphism in intestinal VDR may be contributing to alterations in bone health.
authors.affiliation: Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, USA.
authors.forename: B
authors.initials: B
authors.lastname: Chang
authors.affiliation: Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Schlussel
authors.affiliation: Drexel University, Philadelphia, PA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Sukumar
authors.affiliation: Department of Medicine, Rutgers-Robert Wood Johnson University Hospital, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Schneider
authors.affiliation: Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, USA. Electronic address: shapses@aesop.rutgers.edu.
authors.forename: S A
authors.initials: SA
authors.lastname: Shapses
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D002118:Calcium / Q000378:metabolism*; D031204:Caloric Restriction; D047628:Estrogen Receptor alpha / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011863:Radioimmunoassay; D018167:Receptors, Calcitriol / Q000235:genetics*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D018167:Receptors, Calcitriol; C579457:VDR protein, human; D002118:Calcium
keywords: Calcium absorption; Estrogen receptor (ESR1); Gene polymorphism; Vitamin D receptor (VDR)