<p>Vitamin D Megadose: Definition, Efficacy in Bone Metabolism, Risk of Falls and Fractures</p>

Abstract

Introduction: Currently, approximately more than one billion people around the world are considered to have deficient levels of vitamin D. International consensus recommends vitamin D supplementation to high-risk patients (advanced age, osteoporosis, liver failure, malabsorption syndromes, etc.) and those with levels below 30 ng/mL. There are several vitamin D formulations and dosages available, including megadoses. At the moment, there is no consensus on the definition of megadoses. The purpose of this review is to define what is a megadose and analyze its effectiveness in bone metabolism, risk of fractures and falls. Conclusion: The administration of doses higher than 100,000 IU of vitamin D is considered a megadose. It is evident that the use of megadoses increases serum concentrations of vitamin D; however, there has been no evidence of a decrease in the risk of falls, vertebral fractures or changes in bone mineral density.

The possible double‐edged sword effects of vitamin D on COVID‐19: A hypothesis

“…On these premises, VitD supplementation could be potentially useful in states of vitD deficiency, despite the administration route, such as intramuscular, being questionable as it may change the physiologic effects of VitD (Zheng et al, 2015); As stressed by some randomized controlled trials (RCTs) and observational studies, high‐dose VitD is associated with increased incidence of pathological fractures in the elderly (Sanders et al, 2013), which might be a consequence of cerebellar neuron involvement due to high‐density VitD receptors and central nervous toxicity (Harms et al, 2011) and also that a high‐level of VitD causes 24‐hydroxylase over activation which leads to VitD resistance, which, in turn, can cause a higher cancer incidence as well (Tuohimaa et al, 2004). A newly published review also considered VitD supplements over 100,000 IU as a megadose, which is associated with some adverse effects, and there are no standard recommended dosage except for rough dose ranges than 800 to 6000 IU/day based on the individual's baseline serum VitD and risk factors (Narvaez et al, 2020). Although there is no evidence of VitD mega dose's effect on infectious and inflammatory diseases and the above‐mentioned adverse effect of VitD mega dose, we supposed that possible double‐edged sword effects of VitD on the immune system and infectious conditions might also arise from high/megadose administration which also is out of standard recommendations.…”

“…VitD receptors and central nervous toxicity (Harms et al, 2011) and also that a high-level of VitD causes 24-hydroxylase over activation which leads to VitD resistance, which, in turn, can cause a higher cancer incidence as well (Tuohimaa et al, 2004). A newly published review also considered VitD supplements over 100,000 IU as a megadose, which is associated with some adverse effects, and there are no standard recommended dosage except for rough dose ranges than 800 to 6000 IU/day based on the individual's baseline serum VitD and risk factors (Narvaez et al, 2020). Although there is no evidence of VitD mega dose's effect on infectious and inflammatory diseases and the above-mentioned adverse effect of VitD mega dose, we supposed that possible double-edged sword effects of VitD on the immune system and infectious conditions might also arise from high/megadose administration which also is out of standard recommendations.…”

Nutritional Support for Bariatric Surgery Patients: The Skin beyond the Fat

“…However, given the poor compliance shown by patients in taking supplementation in the post-surgical period, some studies suggest the effectiveness of intramuscular injections of mega doses of 600,000 IU once or twice yearly, without reported side effects or adverse events [ 96 , 98 ]. Vitamin D mega doses did not show any amelioration of the risk of fractures, and in some cases there was even an increasing risk of fractures [ 99 ].…”

Joint position statement on management of patient with osteoporosis during COVID-19 contingency from the AMMOM, CONAMEGER, FELAEN, FEMECOG, FEMECOT, and ICAAFYD

“…Since low serum calcidiol levels are common worldwide, including Latin American countries [ 65 – 67 ], and self-confinement probably decreases sun exposure, a vitamin D dose of 1500 to 2000 IU/day is recommended to reach or maintain adequate serum calcidiol levels, even without a recent determination of vitamin D levels [ 21 , 31 , 68 ]. However, if a marked vitamin D deficiency is observed (≤ 20 ng/mL), a higher supplementation pattern may apply [ 69 ].…”