Dissertation committee:
Δρακούλης Νικόλαος
Αναπληρωτής Καθηγητής, Τομέας Φαρμακευτικής Τεχνολογίας, Τμήμα Φαρμακευτικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Δεμέτζος Κωνσταντίνος
Καθηγητής, Τομέας Φαρμακευτικής Τεχνολογίας, Τμήμα Φαρμακευτικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Χήνου Ιωάννα
Καθηγήτρια, Τομέας Φαρμακογνωσίας και Χημείας Φυσικών Προιόντων, Τμήμα Φαρμακευτικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Χαρμανδάρη Ευαγγελία
Καθηγήτρια, Τμήμα Παιδιατρικής και Εφηβικής Ενδοκρινολογίας, Α’ Παιδιατρική Κλινική, Ιατρική Σχολή, ΕΚΠΑ
Χασαπίδου Μαρία
Καθηγήτρια, Τμήμα Επιστημών Διατροφής και Διαιτολογίας, Διεθνές Πανεπιστήμιο της Ελλάδος
Μπενέτου Βασιλική
Αναπληρώτρια Καθηγήτρια, Εργαστήριο Υγιεινής, Επιδημιολογίας & Ιατρικής Στατιστικής, Ιατρική Σχολή ΕΚΠΑ
Κοντογιάννη Μερόπη
Επίκουρη Καθηγήτρια, Τμήμα Κλινικής Διατροφής, Χαροκόπειο Πανεπιστήμιο
Summary:
Vitamin D is a fat soluble vitamin that can be obtained from dietary sources or synthesized endogenously in the skin from 7-dehydrocholesterol, following exposure to UVB irradiation. Serum concentration of 25(OH)D is the indicated diagnostic biomarker of vitamin D status. Vitamin D is essential for calcium metabolism, skeletal health and neuromuscular function. In addition, vitamin D plays an important role in multiple physiological functions and vitamin D deficiency has been associated with various pathological conditions. Recent data indicate an association between vitamin D deficiency and obesity. In particular, increased Body Mass Index (BMI) has been associated with reduced serum 25(OH)D concentration, but it remains unknown whether reduced serum levels of 25(OH)D are responsible for obesity or vice versa. Also, some studies suggest that body fat mass is inversely related to serum 25(OH)D concentration.
The aim of the present study was to investigate the effect of vitamin D3 supplementation at a dose of 3000 IU via an oral spray on serum 25(OH)D levels, fat mass, total weight loss, BMI and REE during a personalised weight-loss diet program in adult overweight and obese Caucasians with vitamin D deficiency or insufficiency, taking into consideration the possible effect of adrenergic and vitamin D receptor genetic polymorphisms.
This randomized, double-blind, placebo-controlled clinical trial was conducted in the “Athens Euroclinic” hospital and approved by Ethics Committee of “Athens Euroclinic” hospital. After signing informed consent, 125 volunteers who met the inclusion criteria, received the oral vitamin D dietary supplement (Dlux 3000, Better You LTD) or placebo (xylitol, water, mint, Better You LTD) on a daily basis for 3 months, and weight loss program (600 calories less than the total energy expenditure of each volunteer). Fat mass, total body weight, BMI, REE and serum 25(OH)D concentration were measured on starting point and at the end of the study. During the study, REE, BMI and the body fat percentage were measured on a monthly basis. DNA samples were extracted from buccal swabs and genotyped for the rs2228570 (VDR), rs1544410 (VDR), rs731236 (VDR), rs1800544 (ADRA2Α), rs1801252 (ADRB1), rs1042713 (ADRB2) and rs4994 (ADRB3) polymorphisms.
Within group analyses showed a statistically significant increase in serum 25(OH)D concentration (p<0.001) and a decrease in weight, BMI, fat percentage and REE (p<0.001) in the vitamin D group. Accordingly, in the placebo group, a much lower increase in serum 25(OH)D levels (p=0.031) was observed, while a statistically significant decrease in weight, BMI, body fat percentage and REE (p<0.001) was also observed. Between group comparisons revealed statistically significant differences in serum 25(OH)D levels, weight, BMI and body fat percentage. Significant improvement in vitamin D status and reduction in weight, BMI and fat percentage were observed in the vitamin D group compared to placebo group (p<0.05). In the vitamin D group, carriers of the rs2228570 T allele tended to have greater vitamin D level improvement compared with the homozygous C allele (p=0.067). Furthermore, heterozygous (CT) for the rs731236 tended to have lesser weight loss (p=0.068) and for the rs1042713, a significant lower decline in fat percentage was observed for homozygous AA carriers compared with the heterozygous (p=0.051). In the control group, differences in weight loss (p=0.055) and BMI (p=0.045) were observed between rs1544410 AA and GG homozygous.
In conclusion, the results of the present study indicate that vitamin D 3000 IU oral spray supplementation on a daily basis for 3 months in combination with a weight loss program improved 25(OH)D levels and contributed to a greater reduction in body weight, BMI and fat percentage in overweight and obese Caucasian volunteers with vitamin D deficiency or insufficiency. Also, genetic polymorphisms seem to influence vitamin D supplementation response and obesity markers. Further, larger scale studies in Caucasian and non-Caucasian populations are needed in order to validate the results of the present study.
Keywords:
Vitamin D, weight loss, VDR, ADR, pharmacogenomics, obesity
