Circulating pro-inflammatory cytokines are elevated and peak power output correlates with 25-hydroxyvitamin D in vitamin D insufficient adults

Abstract

The purpose of this study was to identify circulating cytokines, skeletal muscle strength, and peak power output in young adults with contrasting serum 25-hydroxyvitamin D (25(OH)D) concentrations. Serum 25(OH)D, inflammatory cytokines, muscle strength, and peak power output were, therefore, measured in young adults (25-42 years). Data were collected during the winter to avoid the seasonal influence on serum 25(OH)D. After serum 25(OH)D concentration measurements, subjects were separated into one of two groups: (1) vitamin D insufficient [serum 25(OH)D ≤32 ng/mL, n = 14], or (2) vitamin D sufficient [serum 25(OH)D >32 ng/mL, n = 14]. Following group allocation, serum 25(OH)D concentrations were significantly (p < 0.05) lower and pro-inflammatory cytokines [interleukin (IL)-2, IL-1β, tumor necrosis factor-α, and interferon-γ] were significantly (all p < 0.05) greater in vitamin D insufficient adults. An anti-inflammatory cytokine (i.e., IL-10; p > 0.05), peak isometric forces (p > 0.05), and peak power outputs (p > 0.05) were not significantly different between vitamin D groups. However, peak power outputs correlated with serum 25(OH)D concentrations in vitamin D insufficient (r = 0.55, p < 0.05) but not in vitamin D sufficient adults (r = -0.27, p = 0.36). Based on these data, we conclude that vitamin D insufficiency, in part, could result in pro-inflammatory stress without altering muscular strength or function in young adults. Future research investigating the causality of the correlation between low-serum 25(OH)D and peak power output in young adults is required.

Supplemental vitamin D increases serum cytokines in those with initially low 25-hydroxyvitamin D: A randomized, double blind, placebo-controlled study

“…In healthy adults, muscle strength was not significantly different despite contrasting serum 25(OH)D with [10] or without [5] supplemental vitamin D. However, a serum 25(OH)D concentration P 30 ng/mL improved strength recovery following anterior cruciate ligament surgery in otherwise healthy adults [46], and supplemental vitamin D (4000 IU/d of cholecalciferol) increased serum 25(OH)D (%47 ng/mL) and enhanced strength recovery following exercise-induced muscle damage in young adults [31]. Based on the evidence, muscle performance at rest or in the absence of injury may not be impaired with a low serum 25(OH)D concentration (e.g., >6 but <29 ng/mL), but maintaining or achieving a sufficient serum 25(OH)D concentration (i.e., P30 ng/mL) could be beneficial on the physical rehabilitation from a muscular or ligamentous injury in physically active and otherwise healthy adults.…”

“…In a previous study, we found a pro-inflammatory cytokine increase in subjects with an insufficient serum 25(OH)D concentration [5]. Therefore, we examined the influence of supplemental vitamin D status at Bsl on serum cytokine changes after supplemental vitamin D. Subjects categorized as vitamin D deficient (serum 25(OH)D < 20 ng/mL) and insufficient (serum 25(OH)D 20-29 ng/mL) before supplementation were pooled into one group due to few subjects in each group respectively (see Table 1).…”

“…The identification of the vitamin D receptor on immune cells [1,2] and the increase in circulating 1,25-dihydroxyvitamin D (1,25(OH)D) concentrations in patients with sarcoidosis [3,4] triggered the regulatory interest of vitamin D on cytokines. Previously, in young adults, low vitamin D (serum 25-hydroxyvitamin D (25(OH)D) 6 32 ng/mL) associated with an increase in tumor necrosis factor (TNF)-a, interferon (IFN)-c, interleukin (IL)-1b, and IL-2 [5]. Consistent with that finding, the seasonal increase in serum 25(OH)D and 1,25(OH)D concentrations during summer associated with a down-regulation in cytokine production [6].…”

The Emerging Biomolecular Role of Vitamin D in Skeletal Muscle

“…Vitamin D status has been associated with reduced circulatory inflammatory markers and concomitant impairments in peak power in healthy adults (4). Serum 25OHD also has been implicated in skeletal muscle recovery after exercise and injury (3,16,41).…”

Influence of Vitamin D Metabolites on Plasma Cytokine Concentrations in Endurance Sport Athletes and on Multiantigen Stimulated Cytokine Production by Whole Blood and Peripheral Blood Mononuclear Cell Cultures

“…Within the general population it has been reported that circulating proinflammatory cytokine concentrations, such as TNF- α , IFN- γ , IL-1 β , and IL-2, were significantly higher in vitamin D insufficient adults compared with those who were vitamin D sufficient [9]. However, to our knowledge, there has been no study to compare the difference in circulating cytokine levels between vitamin D insufficient and sufficient athletes.…”