Effects of vitamin D supplementation on metabolic parameters, serum irisin and obesity values in women with subclinical hypothyroidism: a double-blind randomized controlled trial

Abstract

PurposeSubclinical hypothyroidism is an early, mild form of hypothyroidism that may progress to overt hypothyroidism if untreated. The current study aimed to assess the effects of vitamin D supplementation on hormonal (thyroid stimulating hormone [TSH], triiodothyronine, thyroxine, and free thyroxine) parameters, lipid profiles, serum irisin, and obesity indices in women with subclinical hypothyroidism.MethodsThe present randomized, double-blind, placebo-controlled clinical trial was carried out on 44 women with subclinical hypothyroidism. The participants were allocated to two groups (22 patients in each group) that received vitamin D (50,000 IU/week) or placebo for 12 weeks. Fasting blood samples, anthropometric and body composition measurements, physical activity levels, and dietary intakes were collected at baseline and at the end of the study.ResultsVitamin D supplementation significantly decreased TSH, total cholesterol, and fat mass percentage, and significantly increased serum vitamin D and irisin levels and fat-free mass percentage compared to the control group (all, p<0.05). Changes in thyroid hormones, other lipid profiles, and anthropometric indices were not significantly different between the groups.ConclusionOur study indicates that vitamin D administration improves serum TSH, total cholesterol, irisin, and body composition in women with subclinical hypothyroidism. More well-designed clinical trials are required to confirm these findings and clarify the effects of vitamin D supplementation on both genders of patients.Clinical trial registrationhttps://www.irct.ir/trial/57482, Identifier IRCT20100408003664N25.

Vitamin D and Dyslipidemia: Is There Really a Link? A Narrative Review

“…In 2016, in a randomized placebo-controlled trial conducted on 511 subjects with prediabetes, Jorde also found a significant decrease in LDL-C in the vitamin D supplementation group [ 116 ]. Moreover, the most recent papers show conflicting results on the effect of vitamin D supplementation on dyslipidemia [ 117 , 118 , 119 ]. Table 2 describes the main characteristics of interventional studies.…”

Autoimmunity, New Potential Biomarkers and the Thyroid Gland—The Perspective of Hashimoto’s Thyroiditis and Its Treatment

“…It increases the production of anti-inflammatory cytokines (e.g., IL-10) and T-cell inhibitory molecules (programmed death-1, PD-1), and inhibits the secretion of pro-inflammatory cytokines IL-12, IL-23, TNF-α and IFN-γ, which are involved in the differentiation of T helper cells: Th1 and Th17 [62,63]. According to available literature, vitamin D supplementation may significantly lower TSH and total cholesterol levels, as well as reduce fat mass percentage, increasing irisin levels and fat-free mass percentage in women with subclinical hypothyroidism [64]. According to systematic review and metaanalysis of 12 studies, performed by a group of Tang et al, vitamin D supplementation caused the reduction of anti-TPO and anti-TG antibodies in patients with HT.…”