Vitamin D: Experimental Research and Its Practical Application

High vitamin D and calcium intakes increase bone mineral (Ca and P) content in high-fat diet-induced obese mice

“…It implies that an increased PTH in DIO is not sufficient to increase the 1,25(OH) 2 D 3 production in the kidneys and 1,25(OH) 2 D 3 concentration in blood. Moreover, an increased PTH can be associated with an increased bone resorption, whereas a decreased 1,25(OH) 2 D 3 can impede bone mineralization directly and via reduced intestinal Ca 2+ absorption [5,6].…”

“…The role of mechanical loading in bone formation and remodeling is well established [1][2][3][4][5][6][7][8][9]. In obesity, the excess body weight imposes greater static mechanical loads on bones and is accompanied by an increased bone mineral content and bone mineral density in adults, implying that obesity can be protective against osteoporosis [10].…”

Vitamin D-mediated apoptosis in cancer and obesity

“…Vitamin D status should be carefully defined as sufficient, insufficient, or deficient based on mechanistic studies and direct and indirect evidence-based approach. The US Institute of Medicine (IOM) [22,23], the Endocrine Society [24], the European Food Safety Authority [25], and health regulatory agencies of other European countries [26,27] [1,26,29,30]. Extra-renal production of 1,25(OH) 2 D 3 and its possible significance for paracrine/autocrine regulation of cellular functions is plausible [1,3], but this production does not appear to contribute to maintaining circulating 1,25(OH) 2 It is also worth mentioning that rickets and osteomalacia are observed when 25(OH)D is "undetectable" in blood (usually, it means below 0.5-5 ng/mL depending on the assay) and that the optimal bone growth and remodeling as well as maximum intestinal Ca 2+ absorption [the major physiological functions of 1,25(OH) 2 D 3 ] can be maintained in healthy individuals at 25(OH)D concentrations in the range of 10-20 ng/mL [probably, the lower limit is sufficient because it will not limit the 1,25(OH) 2 D 3 production].…”

Riboflavin‐photosensitized singlet oxygen oxidation product of vitamin D2

“…Both cholecalciferol, D 3 , and ergocalciferol, D 2 , are used in the fortification of milk and infant formulas to help prevent rickets in children and osteomalacia in adults (1). Increased levels of free radicals in animal tissues after dosage with excess levels of vitamin D have been observed by electron spin resonance spectroscopy (3). Increased levels of free radicals in animal tissues after dosage with excess levels of vitamin D have been observed by electron spin resonance spectroscopy (3).…”