1.
The Role of Vitamin C in Two Distinct Physiological States: Physical Activity and Sleep.
Otocka-Kmiecik, A, Król, A
Nutrients. 2020;(12)
Abstract
This paper is a literature overview of the complex relationship between vitamin C and two opposing physiological states, physical activity and sleep. The evidence suggests a clinically important bidirectional association between these two phenomena mediated by different physiological mechanisms. With this in mind, and knowing that both states share a connection with oxidative stress, we discuss the existing body of evidence to answer the question of whether vitamin C supplementation can be beneficial in the context of sleep health and key aspects of physical activity, such as performance, metabolic changes, and antioxidant function. We analyze the effect of ascorbic acid on the main sleep components, sleep duration and quality, focusing on the most common disorders: insomnia, obstructive sleep apnea, and restless legs syndrome. Deeper understanding of those interactions has implications for both public health and clinical practice.
2.
Effects of the Lysulin™ supplementation on pre-diabetes: A randomized double-blind, placebo-controlled clinical trial.
Ranasinghe, P, Jayawardena, R, Chandrasena, L
Diabetes & metabolic syndrome. 2020;(5):1479-1486
Abstract
BACKGROUND AND AIMS Diabetes is a leading cause of morbidity and mortality worldwide. Recent studies have demonstrated that nutraceutical products have beneficial effects in diabetes. Present study aims to investigate whether a product (Lysulin™) containing amino acid lysine, micronutrient zinc and vitamin C will have beneficial effects in pre-diabetes. METHODS A randomized, double-blind, placebo-controlled trial was conducted for a period of 6 months. The two parallel groups (1:1) were Lysulin™ (Interventional group-IG) and placebo (control group-CG). Evaluations were done at baseline, 1, 3 and 6 months. Primary outcome was defined as change in glycaemic control measured by HbA1c from baseline. Other outcomes included change in; fasting plasma glucose (FPG), 2-h OGTT plasma glucose and lipid profile from baseline. Three multiple regression analyses were performed, where change in FPG, 2-h OGTT, and HbA1c post intervention from baseline respectively were the continuous dependent variable with other independent variables. RESULTS One hundred and ten participants were recruited, 50% (n = 55) were males and mean age (±SD) was 46.7 ± 9.9 years. A significantly higher percentage of participants in CG (25.4%, n = 14) developed diabetes in comparison to IG (7.3%, n = 4) (p = 0.018). FPG, 2-h OGTT and HbA1c significantly reduced in the IG only. Both total cholesterol and LDL cholesterol decreased significantly from baseline only in the IG. In all three regression models the best predictor of respective dependent variable was Lysulin™ treatment. CONCLUSIONS Lysulin™ improved glycaemic control, with reduced progression to diabetes, in those with pre-diabetes. Treatment also showed a beneficial reduction in total and LDL cholesterol levels. TRIAL REGISTRATION Sri Lanka Clinical Trials Registry, identifier: SLCTR/2018/022 (http://slctr.lk/trials/1290). Registered on 13th July 2018; Study protocol version 2.0 (23rd March 2018).
3.
Decreased Nuclear Ascorbate Accumulation Accompanied with Altered Genomic Methylation Pattern in Fibroblasts from Arterial Tortuosity Syndrome Patients.
Németh, CE, Nemoda, Z, Lőw, P, Szabó, P, Horváth, EZ, Willaert, A, Boel, A, Callewaert, BL, Coucke, PJ, Colombi, M, et al
Oxidative medicine and cellular longevity. 2019;:8156592
Abstract
Ascorbate requiring Fe2+/2-oxoglutarate-dependent dioxygenases located in the nucleoplasm have been shown to participate in epigenetic regulation of gene expression via histone and DNA demethylation. Transport of dehydroascorbic acid is impaired in the endomembranes of fibroblasts from arterial tortuosity syndrome (ATS) patients, due to the mutation in the gene coding for glucose transporter GLUT10. We hypothesized that altered nuclear ascorbate concentration might be present in ATS fibroblasts, affecting dioxygenase activity and DNA demethylation. Therefore, our aim was to characterize the subcellular distribution of vitamin C, the global and site-specific changes in 5-methylcytosine and 5-hydroxymethylcytosine levels, and the effect of ascorbate supplementation in control and ATS fibroblast cultures. Diminished nuclear accumulation of ascorbate was found in ATS fibroblasts upon ascorbate or dehydroascorbic acid addition. Analyzing DNA samples of cultured fibroblasts from controls and ATS patients, a lower global 5-hydroxymethylcytosine level was found in ATS fibroblasts, which could not be significantly modified by ascorbate addition. Investigation of the (hydroxy)methylation status of specific regions in six candidate genes related to ascorbate metabolism and function showed that ascorbate addition could stimulate hydroxymethylation and active DNA demethylation at the PPAR-γ gene region in control fibroblasts only. The altered DNA hydroxymethylation patterns in patient cells both at the global level and at specific gene regions accompanied with decreased nuclear accumulation of ascorbate suggests the epigenetic role of vitamin C in the pathomechanism of ATS. The present findings represent the first example for the role of vitamin C transport in epigenetic regulation suggesting that ATS is a compartmentalization disease.
4.
The effect of vitamin C and/or E supplementations on type 2 diabetic adult males under metformin treatment: A single-blinded randomized controlled clinical trial.
El-Aal, AA, El-Ghffar, EAA, Ghali, AA, Zughbur, MR, Sirdah, MM
Diabetes & metabolic syndrome. 2018;(4):483-489
Abstract
BACKGROUND AND AIM Recently, there has been an increasing interest in the influence of antioxidant vitamins on the efficacy of oral hypoglycemic therapy in type 2 diabetic patients (T2DM). This single-blinded randomized controlled clinical trial aimed to investigate the effect of vitamin C and/or E supplementation on the efficacy of oral hypoglycemic therapy in T2DM Palestinian male patients from the Gaza Strip. METHODS Forty T2DM male patients aged 40-60 years on metformin treatment were randomly divided into four groups, each group received an additional one of the following daily oral supplements for 90 days: placebo; vitamin C; vitamin E and vitamin C plus vitamin E. After overnight fasting, venous blood specimens were collected from all individuals into K3-EDTA tubes and serum tubes for measuring the biochemical and hematological parameters of the study at baseline and after 90 days of vitamins supplementation. RESULTS The results revealed that vitamin C and/or E improve fasting blood sugar (FBS), HbA1c, lipid profile, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), reduced glutathione (GSH); and Quantitative Insulin Sensitivity Check Index (QISCI) compared with diabetic patients group that received placebo. CONCLUSION This study provided additional evidence on the beneficial effects of supplementing antioxidant vitamins in T2DM which could improve the clinical condition and attenuate or prevent diabetic pathogenesis and complications that, secondly to poor glycemic control, could attribute to the imbalance between the decline in the endogenous antioxidants and increasing production of the reactive oxygen species leading to the oxidant-mediated damage present in the diabetic context.