Vitamin D: not just the bone. Evidence for beneficial pleiotropic extraskeletal effects

Abstract

Vitamin D is a fat-soluble vitamin and a steroid hormone that plays a central role in maintaining calcium-phosphorus and bone homeostasis in close interaction with parathyroid hormone, acting on its classical target tissues, namely, bone, kidney, intestine, and parathyroid glands. However, vitamin D endocrine system regulates several genes (about 3 % of the human genome) involved in cell differentiation, cell-cycle control, and cell function and exerts noncalcemic/pleiotropic effects on extraskeletal target tissues, such as immune and cardiovascular system, pancreatic endocrine cells, muscle, and adipose tissue. Several studies have demonstrated the role of vitamin D supplementation in the prevention/treatment of various autoimmune diseases and improvement of glucose metabolism, muscle, and adipose tissue function. Hence, this review aims to elucidate the effects of vitamin D on extraskeletal target tissues and to investigate the potential therapeutic benefit of vitamin D supplementation among a broad group of pathological conditions, especially with regard to metabolic and autoimmune diseases. In addition, we focused on the best daily intakes and serum levels of vitamin D required for extraskeletal benefits which, even if still controversial, appear to be higher than those widely accepted for skeletal effects.

Association between physical activity and vitamin D: A narrative literature review

“…Obesity has a negative correlation with plasma vitamin D levels, and vitamin D deficiency causes an increased risk for the development of metabolic syndrome, as well as increased oxidative burden. 4 …”

“…Today, this substance is called vitamin D. 4 Physical activity has always existed throughout history, both indoors ( Figure 1) and outdoors 5 ( Figure 2). Millennial accounts of Greeks, Chinese and Indians in relation to the practice of physical activity affirm the idea that a stimulated body becomes strong regardless of variation in the environment.…”

“…It also acts in noncalcemic effects, such as strengthening the immune system, improving balance and preventing premature aging. 4 Researchers' interest in vitamin D has been enhanced by recent advances related to biology, as it plays an important role far beyond calcium metabolism in various extraskeletal tissues such as adipocytes, skeletal striated muscle, and pancreatic tissue. It also participates in the modulation of immunity and inflammation, which shows its therapeutic potential in diseases such as multiple sclerosis, type 1 FIGURE 1 Indoor physical activity.…”

Associations of Vitamin D Receptor Polymorphism rs1544410 with Adiposity Phenotypes

“…Several studies demonstrated the role of vitamin D in obesity through different genetic, experimental, epidemiological and metabolic data linking adipokines with Vitamin D [2][3][4][5]. Vitamin D produces its effects through its binding to vitamin D receptor (VDR); a nuclear transcription factor [6].…”

Structural basis for specific gene regulation by Auxin Response Factors

“…For example, in animals, perception of the hormone acetylcholine triggers contraction in striated muscles, reduces contractions in heart muscle and promotes secretion of digestive enzymes in pancreatic acinar cells 265 ; the hormone progesterone is involved in control of reproduction and sexual behavior but also has effects in the nervous system where it is involved in adult neurogenesis, astroglial and synaptic plasticity, and the myelination process 266 ; vitamin D is involved in calcium-phosphorus maintenance and bone homeostasis, cell differentiation, cell-cycle control, glucose metabolism, muscle and adipose tissue function 267 . This variety of responses is seen also for plant hormones, like auxin.…”