An update on vitamin D for clinicians

Abstract

Purpose of review The clinical benefits of vitamin D therapy have received substantial attention over the past decade. Recently, several trials looked to clarify the optimal vitamin D dose or serum level needed to promote human health. The purpose of this review is to highlight selected studies published since January 2015. Recent findings Several recent trials challenge whether serum vitamin D levels ≥30 ng/mL promote human health. In postmenopausal women with 25(OH)D levels 21±3 ng/mL, high-dose vitamin D for one year increased calcium absorption by 1%, without changes in bone mineral density, physical function, or falls when compared to low-dose vitamin D and placebo. High-dose vitamin D increased risk of falling, in 200 adults 78±5 years old with baseline 25(OH)D levels of ~19±9 ng/mL. High-dose vitamin D in adults increased the number and duration of upper respiratory tract infections, compared to placebo. Asthma patients achieving 25(OH)D levels >30 ng/mL during a trial experienced more respiratory infections than those not achieving such levels. Summary Recent studies are congruent with the Institute of Medicine’s conclusion that humans are vitamin D replete when their serum 25(OH)D levels are ≥20 ng/mL. Higher levels seem to promote falls and respiratory infections.

Vitamin D Levels in COVID-19 Outpatients from Western Mexico: Clinical Correlation and Effect of Its Supplementation

“…Alterations in vitamin D concentrations, either deficiency (serum levels < 20 ng/mL) or insufficiency (serum levels 20–29.9 ng/mL), represent a global health problem [ 27 ]. According to the committee of the Institute of Medicine, people are at risk of the condition called “hypovitaminosis D” at serum concentrations of 25(OH)D < 30 nmol/L (<12 ng/mL) [ 46 ]. It is also well known that differences in geographic location, skin color, and type of diet play an important role in the body disposition and metabolism of vitamin D [ 13 , 14 , 24 ].…”

Vitamin D Daily versus Monthly Administration: Bone Turnover and Adipose Tissue Influences

“…However, after including ethnicity in the model, maternal 25(OH) D during pregnancy was no longer associated with birth weight [21]. On the other hand, optimal serum levels in postmenopausal women could be fundamental for reducing the number falls and preserving muscle function, as well as reducing the occurrence of respiratory infections and colorectal adenomas [22,23]. The complex of ligand-bound VDR with the retinoid-X receptor (RXR) is able to influence gene expression by targeting the response element in the promoter region of specific genes [5]; in addition, calcitriol can activate the intracellular pathways in a manner independent of nuclear VDR binding [17].…”

The Role of Vitamin D in the Immune System as a Pro-survival Molecule

“…[188][189][190] The possibility, therefore, of ascertaining vitamin D's actual part in chronic allergy seems to be hampered by the complex role exerted by this hormonal molecule in innate immunity. [191][192][193][194] Particularly controversial is the role of vitamin D in atopic dermatitis. Vitamin D participates in inducing the thymic stromal lymphopoietin (TSLP)-mediated activation of basophils.…”