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The Effects of Increasing Serum Calcitriol on Energy and Fat Metabolism and Gene Expression
Author(s) -
Boon Niels,
Hul Gabby B. J.,
Sicard Audrey,
Kole Eveline,
Berg Elisa R.,
Viguerie Nathalie,
Langin Dominique,
Saris Wim H. M.
Publication year - 2006
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2006.200
Subject(s) - medicine , endocrinology , calcitriol , cholecalciferol , adipose tissue , lipid metabolism , metabolism , vitamin d and neurology , thermogenesis
Objective: Evidence from a number of investigations indicates that calcium intake could be inversely related to body weight through alterations in the 1,25‐OH 2 ‐D 3 metabolism. The objective of this study was to test whether energy and substrate metabolism and adipose tissue enzyme mRNA expression can be altered by changes in serum 1,25‐OH 2 ‐D 3 through oral cholecalciferol supplementation in non‐obese human subjects. Research Methods and Procedures: An intervention study was used with a treatment period of 7 days. During this intervention, energy expenditure (EE) and substrate metabolism were measured using indirect calorimetry at t = 0, 1, 3, and 7 days, and blood samples were obtained at t = −1, 0, 1, 2, 3, 5 and 7 days. Fat biopsies were obtained at t = 0 and 7 days for determination of expression of genes involved in lipolytic and lipogenic pathways. Subjects from the general community were studied in an ambulatory setting at a university hospital. Ten healthy young men (age, 28 ± 3 years; BMI, 25.5 ± 0.5 kg/m 2 ) were recruited by local announcement, and all completed the study. All subjects received 2000 IU cholecalciferol/d for 7 days, and they were instructed to consume a low‐cholecalciferol, low‐calcium diet. EE, fat oxidation, and adipose tissue enzyme mRNA were the main outcome measures. Results: Despite a significant increase in serum 1,25‐OH 2 ‐D 3 concentration at t = 5 and 7 days, no significant differences in substrate and energy metabolism nor mRNA concentrations of different lipid metabolism‐related proteins were observed. Discussion: Seven‐day supplementation with 2000 IU cholecalciferol/d together with a decrease in dietary calcium intake does not affect EE or substrate metabolism nor gene expression of proteins related to fat metabolism, despite a significant increase in serum 1,25‐OH 2 ‐D 3 concentration.