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The Impact of Vitamin D Supplementation on the IFNγ-IP10 Axis in Women with Hashimoto's Thyroiditis Treated with Levothyroxine: A Double-blind Randomized Placebo-controlled Trial.
Robat-Jazi, B, Mobini, S, Chahardoli, R, Mansouri, F, Nodehi, M, Esfahanian, F, Saboor Yaraghi, AA
Iranian journal of allergy, asthma, and immunology. 2022;21(4):407-417
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Hashimoto’s thyroiditis is an autoimmune disease characterized by the presence of antibodies against thyroid proteins such as thyroperoxidase (TPO) and thyroglobulin (TG), the local accumulation of inflammatory cells and immune-mediated destruction of the thyroid gland. Disease manifestation is due to a genetic disposition but is also influenced by several environmental factors, including stress, smoking, infections, and levels of nutrients like iodine, selenium and vitamin D. Many cells of the immune system have receptors for Vitamin D and thus have the potential to be influenced by Vitamin D. Indeed, numerous findings demonstrated that vitamin D can exert anti-inflammatory effects on the immune system. This double-blind, randomized, placebo-controlled trial investigated 40 Hashimoto's thyroiditis subjects and the effect of Vitamin D supplementation on various markers of the immune system that mediate the inflammatory response as part of the interferon-gamma-induced protein 10 (IFNγ-IP10) axis. 20 of the enrolled candidates received 50000 IU of Vitamin D (cholecalciferol) once a week – an equivalent to about 7140 IU per day - over three months. The other half received a placebo. All candidates had a fixed dose of thyroid hormone replacement levothyroxine for the duration of the trial. Before and after the intervention several blood biomarkers were investigated relating to Vitamin D levels, D-receptors, immune activity and inflammation. Upon completion of the trial, the intervention group who supplemented Vitamin D had significantly higher Vitamin D levels, which had increased from an average of 25.29 ng/ml to 50.65ng/ml. In addition, several inflammatory factors were significantly decreased. These findings affirmed Vitamin D’s ability to favourably regulate the IFNγ-IP10 axis, which could slow disease progression. This effect may also be useful for the management of other autoimmune disorders involving IP10 overproduction, which attracts other inflammatory cells. More studies in larger groups would help to get more information on other variables not considered in this trial.
Abstract
Hashimoto's thyroiditis (HT) results from chemoattraction of inflammatory cells toward the thyroid gland by inducing the production of interferon-gamma (IFNγ)-induced protein 10 (IP10) by T helper (Th) 1 cells. Vitamin D may suppress the IFNγ-IP10 axis, but this new function of vitamin D has not yet been investigated in HT patients. In an intervention and control group, patients received 50000 IU cholecalciferol or placebo every week for three months, respectively. The CD4+ T cells of 40 patients were isolated, and the mRNA expression levels of vitamin D receptor (VDR), peroxisome proliferator-activated receptors (PPAR)-α, and PPAR-γ genes were determined by real-time PCR. ELISA method was used to determine serum levels of vitamin D, tumor necrosis factor-alpha (TNF-α), IFN-γ, and IP10. Vitamin D levels in the intervention group were significantly higher than in the placebo group after supplementation. PPAR-α and PPAR-γ gene expression levels did not differ significantly between the two groups. The serum levels of IP10, IFNγ, and TNF-α decreased significantly in the vitamin D group, as well as in the placebo group. During this study, vitamin D levels significantly increased in the intervention group and inflammatory factors decreased. Based on the similar results obtained in the placebo group, further studies with larger sample sizes and longer intervention times are recommended.
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Effects of vitamin C stimulation on rehabilitation of dysphagia after stroke: a randomized trial.
Wang, J, Chang, E, Jiang, Y
European journal of physical and rehabilitation medicine. 2022;58(4):558-564
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Stroke refers to a clinical syndrome of localized or global brain dysfunction caused by cerebrovascular disease. It has the characteristics of rapid onset, high morbidity, high mortality, and high disability. After a stroke, various dysfunction can be caused, and dysphagia is one of the most common symptoms. The acidity of vitamin C can promote the secretion of saliva by stimulating the tongue, which can accelerate the swallowing action, thereby improving the swallowing function. The aim of this study was to explore the effects of vitamin C stimulation on the rehabilitation process, Nourishment State Index and immune function indicator of stroke patients with dysphagia. This study is a randomised controlled trial which enrolled 120 participants with dysphagia. The participants were randomly assigned into control group and vitamin C stimulation group, with 60 cases in each group. Results show that vitamin C acid stimulation significantly improves rehabilitation, and the Nourishment State Index and Immune Function Index of stroke patients with dysphagia. Authors conclude that Vitamin C acid stimulation can further improve the nutritional status and immune function after stroke and promote post-operative recovery of patients. Thus, vitamin C stimulation therapy can be widely used in stroke rehabilitation management.
Abstract
BACKGROUND Stroke is a clinical syndrome of localized or global brain dysfunction caused by cerebrovascular disease. AIM: The aim of this study was to explore the effect of vitamin C acid stimulation on the rehabilitation process, Nourishment State Index and immune function indicators of stroke patients with dysphagia. DESIGN This is a prospective cohort study. SETTING This study was conducted at our hospital. POPULATION We analyzed stroke patients with dysphagia. METHODS A total of 120 stroke patients with dysphagia were randomly divided into a routine group and a test group, with 60 cases in each group. Routine swallowing training was performed in the routine group, and the test group was stimulated with vitamin C acid. The water swallow test (WST) and video fluoroscopic swallowing study (VFSS) were used to compare the rehabilitation of dysphagia in the two groups. Nourishment State Index was evaluated by BMI, serum albumin, total serum protein and hemoglobin. Immune Function Index was evaluated by IgA, IgM and IgG. RESULTS Compared with the control group, the WST level of patients treated with vitamin C acid stimulation intervention were significantly reduced, and the VFSS score were significantly increased. Serum levels of hemoglobin, albumin, total protein, IgA, IgM and IgG in the vitamin C acid stimulation group were remarkably increased than those in the control group. CONCLUSIONS Vitamin C acid stimulation exhibits a good application effect in patients with dysphagia after stroke. Moreover, vitamin C acid stimulation can further improve the nutritional status and immune function after stroke and promote postoperative recovery of patients. Therefore, we believe that vitamin C stimulation therapy can be widely used in stroke rehabilitation management. CLINICAL REHABILITATION IMPACT Vitamin C acid stimulation significantly improves rehabilitation of stroke patients with dysphagia and ameliorates the nutritional status and immune function of patients.
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Oxidative Stress and Inflammation Are Associated With Age-Related Endothelial Dysfunction in Men With Low Testosterone.
Babcock, MC, DuBose, LE, Witten, TL, Stauffer, BL, Hildreth, KL, Schwartz, RS, Kohrt, WM, Moreau, KL
The Journal of clinical endocrinology and metabolism. 2022;107(2):e500-e514
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Serum testosterone declines gradually with age at a rate of ~1% per year after the third decade. Vascular aging, featuring endothelial dysfunction mediated by oxidative stress and inflammation, is a major risk factor for the development of age-associated cardiovascular disease (CVD). The aim of this study was to examine the effects of low testosterone on cardiovascular aging in men. This study is a cross-sectional study which recruited 58 healthy men of all races/ethnic backgrounds aged 50-75 years (middle-aged/older) and 18-40 years (young). Results show that middle-aged/older men with lower testosterone have evidence of “accelerated” vascular aging, as indicated by a greater age-associated endothelial dysfunction of large arteries compared with their age-matched peers. The greater macrovascular endothelial dysfunction in middle-aged/older men with chronically low testosterone was independent of CVD risk factors or symptoms of androgen deficiency. Furthermore, increased systemic oxidative stress and inflammation are mechanistically linked to the greater age-associated endothelial dysfunction in middle-aged/older men with lower testosterone. Authors conclude that normal physiological levels of testosterone may be beneficial to cardiovascular health by attenuating the age-related decline in endothelial function.
Abstract
CONTEXT Vascular aging, including endothelial dysfunction secondary to oxidative stress and inflammation, increases the risk for age-associated cardiovascular disease (CVD). Low testosterone in middle-aged/older men is associated with increased CVD risk. OBJECTIVE We hypothesized that low testosterone contributes to age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation. METHODS This cross-sectional study included 58 healthy, nonsmoking men categorized as young (N = 20; age 29 ± 4 years; testosterone 500 ± 58 ng/dL), middle-aged/older with higher testosterone (N = 20; age 60 ± 6 years; testosterone 512 ± 115 ng/dL), and middle-aged/older lower testosterone (N = 18; age 59 ± 8 years; testosterone 269 ± 48 ng/dL). Brachial artery flow-mediated dilation (FMDBA) was measured during acute infusion of saline (control) and vitamin C (antioxidant). Markers of oxidative stress (total antioxidant status and oxidized low-density lipoprotein cholesterol), inflammation (interleukin [IL]-6 and C-reactive protein [CRP]), and androgen deficiency symptoms were also examined. RESULTS During saline, FMDBA was reduced in middle-aged/older compared with young, regardless of testosterone status (P < 0.001). FMDBA was reduced in middle-aged/older lower testosterone (3.7% ± 2.0%) compared with middle-aged/older higher testosterone (5.7% ± 2.2%; P = 0.021), independent of symptoms. Vitamin C increased FMDBA (to 5.3% ± 1.6%; P = 0.022) in middle-aged/older lower testosterone but had no effect in young (P = 0.992) or middle-aged/older higher testosterone (P = 0.250). FMDBA correlated with serum testosterone (r = 0.45; P < 0.001), IL-6 (r = -0.41; P = 0.002), and CRP (r = -0.28; P = 0.041). CONCLUSION Healthy middle-aged/older men with low testosterone appear to have greater age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation. These data suggest that low testosterone concentrations may contribute to accelerated vascular aging in men.
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The Effect of Combined Vitamin C and Vitamin E Supplementation on Oxidative Stress Markers in Women with Endometriosis: A Randomized, Triple-Blind Placebo-Controlled Clinical Trial.
Amini, L, Chekini, R, Nateghi, MR, Haghani, H, Jamialahmadi, T, Sathyapalan, T, Sahebkar, A
Pain research & management. 2021;2021:5529741
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Endometriosis (EMS) is a chronic and estrogen-dependent pelvic inflammatory disease that arises from ectopic endometrial implantation and growth outside the uterus cavity. Oxidative stress, an imbalance between reactive oxygen spices and biological antioxidants, could play a key role in EMS pathophysiology. The aim of this study was to evaluate the effect of vitamin C and vitamin E coadministration on oxidative stress (OS) markers as well as pain severity in women with endometriosis. This study is a randomized placebo-controlled clinical trial on 60 reproductive-aged (15–45 years) women with pelvic pain and 1–3 stages of laparoscopic-proven endometriosis. The participants, researchers, and statistician were blind about the groups. The participants were randomly assigned to two groups by the simple randomization method: group A - intervention (n = 30) or group B - palcebo (n = 30). Results show that supplementation with vitamin C and vitamin E effectively reduces systemic OS indices in women with endometriosis. Authors conclude that their findings further support the potential role of antioxidants in the management of EMS.
Abstract
Background: Endometriosis is a chronic and estrogen-dependent pelvic inflammatory disease, which may have various causes, such as oxidative stress. Dysmenorrhea, dyspareunia, and pelvic pain are well-known symptoms of endometriosis. The present clinical trial assessed the role of supplementation with antioxidant vitamins on the indices of oxidative stress as well as the severity of pain in women with endometriosis. Materials and Methods: We enrolled 60 reproductive-aged (15-45 years) women with pelvic pain in this triple-blind clinical trial. They had 1-3 stages of laparoscopic-proven endometriosis. The participants were randomized to group A (n = 30), given vitamin C (1000 mg/day, 2 tablets of 500 mg each) and vitamin E (800 IU/day, 2 tablets of 400 IU each) combination, or group B (n = 30), given placebo pills daily for 8 weeks. Results: Following treatment with vitamin C and vitamin E, we found a significant reduction in MDA and ROS compared with the placebo group. There was no significant decline in total antioxidant capacity after treatment. However, the severity of pelvic pain (p value <0.001), dysmenorrhea (p value <0.001), and dyspareunia (p value <0.001) significantly decreased in the treatment group after 8 weeks of supplementation. Conclusions: The present findings support the potential role of antioxidants in the management of endometriosis. The intake of vitamin C and vitamin E supplements effectively reduced dysmenorrhea severity and improved dyspareunia and severity of pelvic pain.
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The Effect of a Multivitamin and Mineral Supplement on Immune Function in Healthy Older Adults: A Double-Blind, Randomized, Controlled Trial.
Fantacone, ML, Lowry, MB, Uesugi, SL, Michels, AJ, Choi, J, Leonard, SW, Gombart, SK, Gombart, JS, Bobe, G, Gombart, AF
Nutrients. 2020;12(8)
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Vitamins and minerals are essential for a healthy immune system. The prevalence of vitamin and mineral deficiencies increases with age, and this may contribute to age-related decline of the immune system. The aim of this study was to investigate whether a daily multivitamin and mineral (MVM) supplement could improve the immune function of older people. 42 healthy adults aged between 55 and 75 took part in this single-centre, two-armed, parallel, randomised, double-blinded study. Half of the group was given a MVM supplement called Redoxon Vita Immune (VI) containing the vitamins A, D, E, C, B6, B12 and folate plus iron, copper, zinc and selenium daily for 12 weeks, whilst the other half was given placebo tablets for 12 weeks. Participants were instructed to avoid certain foods high in vitamins and minerals such as oily fish, red meat, liver, and citrus fruits during the study period. Blood and saliva samples were taken from all participants at the beginning and end of the study period, to measure vitamin and mineral status and markers of immune function. Participants also kept a diary to record any illnesses or symptoms. At the end of the study, participants given the MVM supplement had increased their blood levels of vitamin C by 126% and zinc by 43%. There was no significant change in blood levels of vitamin D. There was no significant difference in the potential of blood to kill the introduced bacteria Staphylococcus aureus, or in neutrophil activity, nor were there any significant changes in blood levels of cytokines and chemokines. Participants taking the supplement did however report a shorter length, and lower severity of illnesses compared to those taking the placebo. The authors concluded that their findings support further research to test whether MVM supplementation can improve immune outcomes in older adults.
Abstract
Older adults are at increased risk for vitamin and mineral deficiencies that contribute to age-related immune system decline. Several lines of evidence suggest that taking a multi-vitamin and mineral supplement (MVM) could improve immune function in individuals 55 and older. To test this hypothesis, we provided healthy older adults with either an MVM supplement formulated to improve immune function (Redoxon® VI, Singapore) or an identical, inactive placebo control to take daily for 12 weeks. Prior to and after treatment, we measured (1) their blood mineral and vitamin status (i.e., vitamin C, zinc and vitamin D); (2) immune function (i.e., whole blood bacterial killing activity, neutrophil phagocytic activity, and reactive oxygen species production); (3) immune status (salivary IgA and plasma cytokine/chemokine levels); and (4) self-reported health status. MVM supplementation improved vitamin C and zinc status in blood and self-reported health-status without altering measures of immune function or status or vitamin D levels, suggesting that healthy older adults may benefit from MVM supplementation. Further development of functional assays and larger study populations should improve detection of specific changes in immune function after supplementation in healthy older adults. Clinical Trials Registration: ClinicalTrials.gov #NCT02876315.
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Unusual Early Recovery of a Critical COVID-19 Patient After Administration of Intravenous Vitamin C.
Waqas Khan, HM, Parikh, N, Megala, SM, Predeteanu, GS
The American journal of case reports. 2020;21:e925521
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Coronavirus disease (Covid-19) continues to spread globally and to date there are no proven treatments. Current treatment focuses on the management of the associated acute respiratory distress syndrome (ARDS). There are many studies demonstrating that in severe sepsis and ARDS; Vitamin C reduces systemic inflammation, prevents lung damage, reduces the duration of mechanical ventilation (MV) and the length of intensive care unit (ICU) stay in patients. This is a case report where a critically ill patient received high-dose Vitamin C intravenous (IV) infusions and recovered. A 74 year-old woman with Covid-19, developed ARDS and septic shock. Usual medications were given. She needed MV and deteriorated rapidly. On Day 7 she was administered Vitamin C (11g per 24 hours as a continuous IV infusion). Her clinical condition improved slowly after this. In this case, high dose IV Vitamin C was associated with fewer days on mechanical intervention, a shorter ICU stay and earlier recovery. These results show the importance of further investigation of IV Vitamin C to assess its efficacy in critically ill Covid-19 patients requiring mechanical ventilation and ICU care.
Abstract
BACKGROUND Coronavirus disease 2019 (COVID-19) continues to spread, with confirmed cases now in more than 200 countries. Thus far there are no proven therapeutic options to treat COVID-19. We report a case of COVID-19 with acute respiratory distress syndrome who was treated with high-dose vitamin C infusion and was the first case to have early recovery from the disease at our institute. CASE REPORT A 74-year-old woman with no recent sick contacts or travel history presented with fever, cough, and shortness of breath. Her vital signs were normal except for oxygen saturation of 87% and bilateral rhonchi on lung auscultation. Chest radiography revealed air space opacity in the right upper lobe, suspicious for pneumonia. A nasopharyngeal swab for severe acute respiratory syndrome coronavirus-2 came back positive while the patient was in the airborne-isolation unit. Laboratory data showed lymphopenia and elevated lactate dehydrogenase, ferritin, and interleukin-6. The patient was initially started on oral hydroxychloroquine and azithromycin. On day 6, she developed ARDS and septic shock, for which mechanical ventilation and pressor support were started, along with infusion of high-dose intravenous vitamin C. The patient improved clinically and was able to be taken off mechanical ventilation within 5 days. CONCLUSIONS This report highlights the potential benefits of high-dose intravenous vitamin C in critically ill COVID-19 patients in terms of rapid recovery and shortened length of mechanical ventilation and ICU stay. Further studies will elaborate on the efficacy of intravenous vitamin C in critically ill COVID-19.
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Vitamin C levels in patients with SARS-CoV-2-associated acute respiratory distress syndrome.
Chiscano-Camón, L, Ruiz-Rodriguez, JC, Ruiz-Sanmartin, A, Roca, O, Ferrer, R
Critical care (London, England). 2020;24(1):522
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Sepsis related acute respiratory disease (ARDS) is associated with Covid-19. ARDS patients can present with decreased levels of vitamin C and so by association Covid-19 patients may also have low vitamin C levels. In this cohort study, 18 Covid-19 ARDS patients of which all survived were assessed for vitamin C levels. 17 patients had undetectable levels of vitamin C and one had low levels. It was concluded that more than 90% of the patients in this study had undetectable levels of vitamin C, which may be due to several reasons, such as reduced absorption of vitamin C in the gut and decreased production. Clinicians could use this study to understand the importance of monitoring vitamin C levels in patients with Covid-19.
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Behaviour change, weight loss and remission of Type 2 diabetes: a community-based prospective cohort study.
Dambha-Miller, H, Day, AJ, Strelitz, J, Irving, G, Griffin, SJ
Diabetic medicine : a journal of the British Diabetic Association. 2020;37(4):681-688
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Type 2 Diabetes is considered a lifelong condition, but calorie restriction or weight loss can lead to complete remission. Patients newly diagnosed with Type 2 Diabetic may benefit from behavioural change over the long run. When Type 2 Diabetes is diagnosed early in the disease trajectory, it may increase the patient's motivation and make them more receptive to weight-loss interventions. This prospective cohort study included 865 newly diagnosed Type 2 diabetic patients from the ADDICTION Cambridge Trial, a pragmatic, parallel-group cluster randomised controlled trial. The study assessed the relationship between behaviour change and weight loss and the prospect of type 2 diabetes remission in the first year, following four years and after five years without intense dietary or lifestyle intervention in patients. 30% of the patients achieved diabetes remission at 5-year follow-up, with a significant likelihood of remission among those who achieved ≥ 10% weight loss in the first year of diagnosis. A self-reported change in intake of alcohol units was found to be the only consistent association between behaviour change and remission in this study. The role of behaviour change in the remission of diabetes requires further robust research. This study will help healthcare professionals understand the association between weight loss and remission in diabetic patients.
Abstract
AIM: To quantify the association between behaviour change and weight loss after diagnosis of Type 2 diabetes, and the likelihood of remission of diabetes at 5-year follow-up. METHOD We conducted a prospective cohort study in 867 people with newly diagnosed diabetes aged 40-69 years from the ADDITION-Cambridge trial. Participants were identified via stepwise screening between 2002 and 2006, and underwent assessment of weight change, physical activity (EPAQ2 questionnaire), diet (plasma vitamin C and self-report), and alcohol consumption (self-report) at baseline and 1 year after diagnosis. Remission was examined at 5 years after diabetes diagnosis via HbA1c level. We constructed log binomial regression models to quantify the association between change in behaviour and weight over both the first year after diagnosis and the subsequent 1-5 years, as well as remission at 5-year follow-up. RESULTS Diabetes remission was achieved in 257 participants (30%) at 5-year follow-up. Compared with people who maintained the same weight, those who achieved ≥ 10% weight loss in the first year after diagnosis had a significantly higher likelihood of remission [risk ratio 1.77 (95% CI 1.32 to 2.38; p<0.01)]. In the subsequent 1-5 years, achieving ≥10% weight loss was also associated with remission [risk ratio 2.43 (95% CI 1.78 to 3.31); p<0.01]. CONCLUSION In a population-based sample of adults with screen-detected Type 2 diabetes, weight loss of ≥10% early in the disease trajectory was associated with a doubling of the likelihood of remission at 5 years. This was achieved without intensive lifestyle interventions or extreme calorie restrictions. Greater attention should be paid to enabling people to achieve weight loss following diagnosis of Type 2 diabetes.
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Estimating Vitamin C Status in Critically Ill Patients with a Novel Point-of-Care Oxidation-Reduction Potential Measurement.
Rozemeijer, S, Spoelstra-de Man, AME, Coenen, S, Smit, B, Elbers, PWG, de Grooth, HJ, Girbes, ARJ, Oudemans-van Straaten, HM
Nutrients. 2019;11(5)
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This cohort study examines Vitamin C status as a functional measure in critically ill ICU patients with those of healthy volunteers. Vitamin C deficiency is common in critically ill patients and so establishing vitC status in everyday clinical practise may help quickly identify patients who might benefit from vitamin C supplementation. Common practise is to measure plasma concentrations using timely and expensive high-pressure liquid chromatography. A new point-of-care device enables clinicians to measure the static oxidation-reduction potential (sORP), reflecting oxidative stress, and antioxidant capacity (AOC) as functional indicators of vitC status. This cohort study measured sORP and AOC in 211 samples taken from 103 subjects in stored plasma samples taken from two 2015 studies; an observational vitamin C status study and a randomized pharmacokinetics study. Normal plasma vitC concentrations were defined as 23 to 100 µmol/L whilst deficiency is defined as <11 µmol/L. The results showed that VitC concentrations were negatively associated with sORP (R2 = 0.816) and positively associated with AOC (R2 = 0.842) indicating oxidative stress and vitamin C deficiency. This novel device may help facilitate speedy measurement of vitC status to identify critically ill patients who could benefit from vitC therapy.
Abstract
Vitamin C deficiency is common in critically ill patients. Vitamin C, the most important antioxidant, is likely consumed during oxidative stress and deficiency is associated with organ dysfunction and mortality. Assessment of vitamin C status may be important to identify patients who might benefit from vitamin C administration. Up to now, vitamin C concentrations are not available in daily clinical practice. Recently, a point-of-care device has been developed that measures the static oxidation-reduction potential (sORP), reflecting oxidative stress, and antioxidant capacity (AOC). The aim of this study was to determine whether plasma vitamin C concentrations were associated with plasma sORP and AOC. Plasma vitamin C concentration, sORP and AOC were measured in three groups: healthy volunteers, critically ill patients, and critically ill patients receiving 2- or 10-g vitamin C infusion. Its association was analyzed using regression models and by assessment of concordance. We measured 211 samples obtained from 103 subjects. Vitamin C concentrations were negatively associated with sORP (R2 = 0.816) and positively associated with AOC (R2 = 0.842). A high concordance of 94-100% was found between vitamin C concentration and sORP/AOC. Thus, plasma vitamin C concentrations are strongly associated with plasma sORP and AOC, as measured with a novel point-of-care device. Therefore, measuring sORP and AOC at the bedside has the potential to identify and monitor patients with oxidative stress and vitamin C deficiency.
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Effects of ascorbic acid supplementation on oxidative stress markers in healthy women following a single bout of exercise.
Yimcharoen, M, Kittikunnathum, S, Suknikorn, C, Nak-On, W, Yeethong, P, Anthony, TG, Bunpo, P
Journal of the International Society of Sports Nutrition. 2019;16(1):2
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Moderately intense exercise often causes muscle damage, which initiates an acute inflammatory response. Vitamin C or ascorbic acid is suggested to provide antioxidant protection against oxidative stress. The efficacy of ascorbic acid supplementation on exercise-induced oxidative stress remains unclear. The aim of this crossover study was to determine the effects of ascorbic acid supplementation on circulating biomarkers of oxidative stress and muscle damage in 19 healthy women after a single bout of moderately-intense exercise. Participants performed 30 minutes of cycling after ingesting 1000 mg of ascorbic acid or placebo with a one-week washout period. Blood samples were taken before exercise, immediately after and 30 minutes post-exercise to determine various markers of oxidative stress and muscle damage. This study found ascorbic acid supplementation prior to moderately-intense exercise improves antioxidant capacity but does not prevent muscle damage. The exercise performed in this study did not induce systemic inflammation, only low-grade muscle damage. Based on these results, the authors suggest further investigation of the effects of ascorbic acid supplementation during exercise be done to better understand the molecular interactions of ascorbic acid during exercise.
Abstract
BACKGROUND Ascorbic acid is a water-soluble chain breaking antioxidant. It scavenges free radicals and reactive oxygen species (ROS), which are produced during metabolic pathways. Exercise can produce an imbalance between ROS and antioxidants, leading to oxidative stress-related tissue damages. This study was designed to determine the effects of ascorbic acid supplementation on circulating biomarkers of oxidative stress and muscle damage following a single bout of exercise. METHODS In a crossover design with a 1 wk. wash-out period, 19 healthy women performed 30 min moderate-intensity cycling after ingesting 1000 mg of ascorbic acid (AA) or placebo. Blood samples were taken immediately before, immediately after and 30 min post-exercise to determine plasma albumin, total protein, glucose, oxidative stress and muscle damage markers. RESULTS Plasma albumin and total protein levels increased immediately after exercise in placebo alongside slight reductions in glucose (p = 0.001). These effects were absent in AA cohort. Ferric reducing ability of plasma and vitamin C levels in AA cohort significantly increased after exercise (p < 0.05). Superoxide dismutase activity was significantly elevated after exercise (p = 0.002) in placebo but not AA. Plasma malondialdehyde did not change after exercise in placebo but was significantly decreased in AA (p < 0.05). The exercise protocol promoted slight muscle damage, reflected in significant increases in total creatine kinase in all subjects after exercise. On the other hand, plasma C-reactive protein and lactate dehydrogenase remained unchanged. CONCLUSION Supplementation with ascorbic acid prior exercise improves antioxidant power but does not prevent muscle damage.