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Park JH, Lee Y, Choi M, Park E. The Role of Some Vitamins in Respiratory-related Viral Infections: A Narrative Review. Clin Nutr Res 2023; 12:77-89. [PMID: 36793782 PMCID: PMC9900078 DOI: 10.7762/cnr.2023.12.1.77] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 01/19/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023] Open
Abstract
This study aimed to find out the effect of vitamins on respiratory-related viral infections, including coronavirus disease 2019 (COVID-19), through the literature reviews. From January 2000 to June 2021, the studies (cohort studies, cross-sectional studies, case-control studies, randomized control trials) related to vitamins (vitamin A, D, E, C, B6, folate, and B12) and COVID-19/severe acute respiratory syndrome/Middle East respiratory syndrome/cold/influenza were selected from the PubMed, Embase, and Cochrane libraries and analyzed. The relationship between vitamins and virus-related respiratory diseases was identified. Through the review, 39 studies were selected on vitamin D, one study on vitamin E, 11 studies on vitamin C, and 3 studies on folate. Regarding COVID-19, 18 studies on vitamin D, 4 studies on vitamin C, and 2 studies on folate showed significant effects of the intake of these nutrients in preventing COVID-19. Regarding colds and influenza, 3 studies on vitamin D, 1 study on vitamin E, 3 studies on vitamin C, and 1 study on folate demonstrated that the intake of these nutrients significantly prevents these diseases. Therefore, this review suggested the intake of vitamins D, E, C, and folate is important for preventing respiratory diseases related to viruses, such as COVID-19, colds, and influenza. The relationship between these nutrients and virus-related respiratory diseases should be continuously monitored in the future.
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Affiliation(s)
- Jae-Hee Park
- Department of Food and Nutrition, Kyungnam University, Changwon 51767, Korea
| | - Yunjung Lee
- Department of Food and Nutrition, Kyungnam University, Changwon 51767, Korea
| | - Mijoo Choi
- Department of Food and Nutrition, Kyungnam University, Changwon 51767, Korea
| | - Eunju Park
- Department of Food and Nutrition, Kyungnam University, Changwon 51767, Korea
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Majdan M, Bobrowska-Korczak B. Active Compounds in Fruits and Inflammation in the Body. Nutrients 2022; 14:nu14122496. [PMID: 35745226 PMCID: PMC9229651 DOI: 10.3390/nu14122496] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 12/10/2022] Open
Abstract
Inflammation plays an important role in the pathogenesis of many diseases, including cardiovascular diseases, atherosclerosis, diabetes, asthma, and cancer. An appropriate diet and the active compounds contained in it can affect various stages of the inflammatory process and significantly affect the course of inflammatory diseases. Recent reports indicate that polyphenolic acids, vitamins, minerals, and other components of fruits may exhibit activity stimulating an anti-inflammatory response, which may be of importance in maintaining health and reducing the risk of disease. The article presents the latest data on the chemical composition of fruits and the health benefits arising from their anti-inflammatory and antioxidant effects. The chemical composition of fruits determines their anti-inflammatory and antioxidant properties, but the mechanisms of action are not fully understood.
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High-Dose Vitamin C for Cancer Therapy. Pharmaceuticals (Basel) 2022; 15:ph15060711. [PMID: 35745630 PMCID: PMC9231292 DOI: 10.3390/ph15060711] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 12/24/2022] Open
Abstract
In recent years, the idea that Vitamin C (Vit-C) could be utilized as a form of anti-cancer therapy has generated many contradictory arguments. Recent insights into the physiological characteristics of Vit-C, its pharmacokinetics, and results from preclinical reports, however, suggest that high-dose Vit-C could be effectively utilized in the management of various tumor types. Studies have shown that the pharmacological action of Vit-C can attack various processes that cancerous cells use for their growth and development. Here, we discuss the anti-cancer functions of Vit-C, but also the potential for the use of Vit-C as an epigenetic regulator and immunotherapy enhancer. We also provide a short overview of the current state of systems for scavenging reactive oxygen species (ROS), especially in the context of their influencing high-dose Vit-C toxicity for the inhibition of cancer growth. Even though the mechanisms of Vit-C action are promising, they need to be supported with robust randomized and controlled clinical trials. Moreover, upcoming studies should focus on how to define the most suitable cancer patient populations for high-dose Vit-C treatments and develop effective strategies that combine Vit-C with various concurrent cancer treatment regimens.
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Vlieg‐ Boerstra B, Jong N, Meyer R, Agostoni C, De Cosmi V, Grimshaw K, Milani GP, Muraro A, Oude Elberink H, Pali‐ Schöll I, Roduit C, Sasaki M, Skypala I, Sokolowska M, Splunter M, Untersmayr E, Venter C, O’Mahony L, Nwaru BI. Nutrient supplementation for prevention of viral respiratory tract infections in healthy subjects: A systematic review and meta-analysis. Allergy 2022; 77:1373-1388. [PMID: 34626488 DOI: 10.1111/all.15136] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/08/2021] [Accepted: 08/24/2021] [Indexed: 12/11/2022]
Abstract
It remains uncertain as to whether nutrient supplementation for the general population considered healthy could be useful in the prevention of RTIs, such as COVID-19. In this systematic review and meta-analysis, the evidence was evaluated for primary prevention of any viral respiratory tract infection (RTI) such as SARS-CoV-2, through supplementation of nutrients with a recognized role in immune function: multiple micronutrients, vitamin A, folic acid, vitamin B12, C, D, E, beta-carotene, zinc, iron and long-chain polyunsaturated fatty acids. The search produced 15,163 records of which 93 papers (based on 115 studies) met the inclusion criteria, resulting in 199,055 subjects (191,636 children and 7,419 adults) from 37 countries. Sixty-three studies were included in the meta-analyses, which was performed for children and adults separately. By stratifying the meta-analysis by world regions, only studies performed in Asia showed a significant but heterogeneous protective effect of zinc supplementation on RTIs (RR 0.86, 95% CI 0.7-0.96, I2 = 79.1%, p = .000). Vitamin D supplementation in adults significantly decreased the incidence of RTI (RR 0.89, 95% CI 0.79-0.99, p = .272), particularly in North America (RR 0.82 95% CI 0.68-0.97), but not in Europe or Oceania. Supplementation of nutrients in the general population has either no or at most a very limited effect on prevention of RTIs. Zinc supplementation appears protective for children in Asia, whilst vitamin D may protect adults in the USA and Canada. In 10/115 (8.7%) studies post-hoc analyses based on stratification for nutritional status was performed. In only one study zinc supplementation was found to be more effective in children with low zinc serum as compared to children with normal zinc serum levels.
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Affiliation(s)
| | - Nicolette Jong
- Internal Medicine Allergology & Clinical Immunology Erasmus MC University Medical Centre Rotterdam Rotterdam The Netherlands
- Paediatric Allergology Sophia Children Hospital ErasmusMC University Medical Centre Rotterdam Rotterdam The Netherlands
| | - Rosan Meyer
- National Heart & Lung Institute Imperial College London London UK
| | - Carlo Agostoni
- Pediatric Unit Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
- Department of Clinical Sciences and Community Health Università degli Studi di Milano Milan Italy
| | - Valentina De Cosmi
- Pediatric Unit Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
- Department of Clinical Sciences and Community Health Università degli Studi di Milano Milan Italy
| | - Kate Grimshaw
- University Child Health University of Southampton Southampton General Hospital Southampton UK
| | - Gregorio Paolo Milani
- Pediatric Unit Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan Italy
- Department of Clinical Sciences and Community Health Università degli Studi di Milano Milan Italy
| | - Antonella Muraro
- Food Allergy Referral Centre Department of Woman and Child Health Padua University Hospital Padua Italy
| | - Hanneke Oude Elberink
- Department of Internal Medicine, Allergology University Medical Centre Groningen Groningen The Netherlands
| | - Isabella Pali‐ Schöll
- Interuniversity Messerli Research Institute Comparative Medicine University of Veterinary Medicine and Medical University Vienna Vienna Austria
- Institute of Pathophysiology and Allergy Research Center for Pathophysiology, Infectiology and Immunology Medical University of Vienna Vienna Austria
| | - Caroline Roduit
- University Children's Hospital Zurich Zurich Switzerland
- Christine Kühne‐Center for Allergy Research and Education (CK‐CARE) Davos Switzerland
- Children's Hospital of Eastern Switzerland St Gallen Switzerland
| | - Mari Sasaki
- Department of Immunology and Allergy University Children's Hospital Zurich Zurich Switzerland
| | - Isabel Skypala
- National Heart & Lung Institute Imperial College London London UK
- Department of Allergy & Clinical Immunology Royal Brompton & Harefield NHS Foundation Trust London UK
| | - Milena Sokolowska
- Swiss Institute of Allergy and Asthma Research (SIAF) University of Zurich Davos Switzerland
| | - Marloes Splunter
- Internal Medicine Allergology & Clinical Immunology Erasmus MC University Medical Centre Rotterdam Rotterdam The Netherlands
| | - Eva Untersmayr
- Institute of Pathophysiology and Allergy Research Center for Pathophysiology, Infectiology and Immunology Medical University of Vienna Vienna Austria
| | - Carina Venter
- Section of Allergy and Immunology Children’s Hospital Colorado University of Colorado Denver Colorado USA
| | - Liam O’Mahony
- Department of Medicine and Microbiology APC Microbiome Ireland National University of Ireland Cork Ireland
| | - Bright I Nwaru
- Krefting Research Centre Institute of Medicine University of Gothenburg Gothenburg Sweden
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Michailides C, Velissaris D. Common anti-oxidant vitamin C as an anti-infective agent with remedial role on SARS-CoV-2 infection. An update. Monaldi Arch Chest Dis 2021; 91. [PMID: 34284566 DOI: 10.4081/monaldi.2021.1808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/26/2021] [Indexed: 01/08/2023] Open
Abstract
Coronavirus disease -2019 (COVID-19) has led to a worldwide multifaceted crisis. The medical world agonizes to contend with the problem, but a string of tested medications has been proven unavailing. Vitamin C is well described as a salutary antioxidant and some trials conclude that it may be a potential antiviral drug. In high doses, Vitamin C can alternate crucial steps in the pathogenesis of sepsis and acute respiratory distress syndrome. This dynamic was the driving force behind trials around the world that tried immunonutrition as a weapon against clinical entities. We summarize the mechanisms of action of Vitamin C and its role against infections and the current literature referring to the potential role of Vitamin C in SARS-CoV-2 infection, also as a contingent treatment agent.
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Investigation of Serum and Leukocyte Ascorbic Acid, Plasma and Intra-Erythrocyte Cholinesterase Levels in Obese Persons. JOURNAL OF CONTEMPORARY MEDICINE 2021. [DOI: 10.16899/jcm.841743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abioye AI, Bromage S, Fawzi W. Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis. BMJ Glob Health 2021; 6:bmjgh-2020-003176. [PMID: 33472840 PMCID: PMC7818810 DOI: 10.1136/bmjgh-2020-003176] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 11/30/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
Acute respiratory tract infections (ARIs) are a leading cause of ill-health and death globally. Individual or multiple micronutrients have been shown to modulate immune function and affect the risk and severity of a number of infectious diseases. We systematically reviewed the evidence on the impact of micronutrient supplements to reduce the occurrence of ARIs and shorten the duration of ARI symptoms among adults. Random effects meta-analyses were conducted to estimate the pooled effects of vitamin D, vitamin C, zinc and multiple micronutrient supplementation (MMS) on the occurrence of ARIs and the duration of ARI symptoms. Vitamin D supplementation reduced the risk of ARI (risk ratio (RR)=0.97; 95% CI 0.94 to 1.00; p=0.028) and shortened the duration of symptoms (per cent difference: −6% (95% CI −9% to −2%; p=0.003)). The RR of vitamin D to prevent ARI was farther from the null when diagnosis was based on clinical diagnosis or laboratory testing, compared with self-report and when the loading dose was <60 000 IU. Vitamin C supplementation reduced the risk of ARIs (RR=0.96; 95% CI 0.93 to 0.99; p=0.01) and shortened the duration of symptoms (per cent difference: −9% (95% CI −16% to −2%; p=0.014)). The effect of vitamin C on preventing ARI was stronger among men and in middle-income countries, compared with women and high-income countries, respectively. Zinc supplementation did not reduce the risk of ARIs but shortened the duration of symptoms substantially (per cent difference: −47% (95% CI −73% to −21%; p=0.0004)). Our synthesis of global evidence from randomised controlled trials indicates that micronutrient supplements including zinc, vitamins C and D, and multiple micronutrient supplements may be modestly effective in preventing ARIs and improving their clinical course. Further research is warranted to better understand the effectiveness that individual or multiple micronutrients have on SARS-CoV-2 infection and treatment outcomes.
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Affiliation(s)
- Ajibola Ibraheem Abioye
- Department of Nutrition, Harvard University T H Chan School of Public Health, Boston, Massachusetts, USA
| | - Sabri Bromage
- Department of Nutrition, Harvard University T H Chan School of Public Health, Boston, Massachusetts, USA
| | - Wafaie Fawzi
- Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, Massachusetts, USA
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Holford P, Carr AC, Jovic TH, Ali SR, Whitaker IS, Marik PE, Smith AD. Vitamin C-An Adjunctive Therapy for Respiratory Infection, Sepsis and COVID-19. Nutrients 2020; 12:E3760. [PMID: 33297491 PMCID: PMC7762433 DOI: 10.3390/nu12123760] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/27/2020] [Accepted: 12/03/2020] [Indexed: 12/15/2022] Open
Abstract
There are limited proven therapies for COVID-19. Vitamin C's antioxidant, anti-inflammatory and immunomodulating effects make it a potential therapeutic candidate, both for the prevention and amelioration of COVID-19 infection, and as an adjunctive therapy in the critical care of COVID-19. This literature review focuses on vitamin C deficiency in respiratory infections, including COVID-19, and the mechanisms of action in infectious disease, including support of the stress response, its role in preventing and treating colds and pneumonia, and its role in treating sepsis and COVID-19. The evidence to date indicates that oral vitamin C (2-8 g/day) may reduce the incidence and duration of respiratory infections and intravenous vitamin C (6-24 g/day) has been shown to reduce mortality, intensive care unit (ICU) and hospital stays, and time on mechanical ventilation for severe respiratory infections. Further trials are urgently warranted. Given the favourable safety profile and low cost of vitamin C, and the frequency of vitamin C deficiency in respiratory infections, it may be worthwhile testing patients' vitamin C status and treating them accordingly with intravenous administration within ICUs and oral administration in hospitalised persons with COVID-19.
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Affiliation(s)
- Patrick Holford
- Institute for Optimum Nutrition, Ambassador House, Richmond TW9 1SQ, UK
| | - Anitra C. Carr
- Nutrition in Medicine Research Group, Department of Pathology & Biomedical Science, University of Otago, Christchurch 8140, New Zealand;
| | - Thomas H. Jovic
- Reconstructive Surgery & Regenerative Medicine Research Group, Institute of Life Sciences, Swansea University Medical School, Swansea University, Swansea SA2 8PY, UK; (T.H.J.); (S.R.A.); (I.S.W.)
- Welsh Centre for Burns & Plastic Surgery, Morriston Hospital, Swansea SA6 6NL, UK
| | - Stephen R. Ali
- Reconstructive Surgery & Regenerative Medicine Research Group, Institute of Life Sciences, Swansea University Medical School, Swansea University, Swansea SA2 8PY, UK; (T.H.J.); (S.R.A.); (I.S.W.)
- Welsh Centre for Burns & Plastic Surgery, Morriston Hospital, Swansea SA6 6NL, UK
| | - Iain S. Whitaker
- Reconstructive Surgery & Regenerative Medicine Research Group, Institute of Life Sciences, Swansea University Medical School, Swansea University, Swansea SA2 8PY, UK; (T.H.J.); (S.R.A.); (I.S.W.)
- Welsh Centre for Burns & Plastic Surgery, Morriston Hospital, Swansea SA6 6NL, UK
| | - Paul E. Marik
- Division of Pulmonary and Critical Care Medicine, Eastern Virginia Medical School, Norfolk, VA 23507, USA;
| | - A. David Smith
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK;
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Kim TK, Lim HR, Byun JS. Vitamin C supplementation reduces the odds of developing a common cold in Republic of Korea Army recruits: randomised controlled trial. BMJ Mil Health 2020; 168:117-123. [PMID: 32139409 DOI: 10.1136/bmjmilitary-2019-001384] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 11/03/2022]
Abstract
INTRODUCTION The Republic of Korea (ROK) military has a high incidence of respiratory diseases at training centres. Vitamin C has been reported to reduce the incidence of colds. For the purpose of preventing soldiers' respiratory diseases, this study aimed to investigate whether vitamin C intake can prevent common colds in the ROK Army soldiers. METHODS This was a randomised, placebo-controlled, and double-blind trial of soldiers who enlisted in the Korea Army Training Centre for 30 days from 12 February to 13 March 2018. The study participants were divided into groups (vitamin C vs placebo). The military medical records were searched to determine whether the participants had a common cold. Multiple logistic regression analysis was performed to identify the association between vitamin C intake and diagnosis of common colds. In addition, subgroup analysis on the relationship between vitamin C intake and common cold according to smoking status, training camp and physical rank was conducted. RESULTS A total of 1444 participants were included in our study. Of these participants, 695 received vitamin C (6000 mg/day, vitamin C group), while 749 participants received placebo (0 mg/day, placebo group). The vitamin C group had a 0.80-fold lower risk of getting a common cold than did the placebo group. Subgroup analyses showed that this effect was stronger among subjects in camp A, among never smokers and among those in physical rank 3. CONCLUSION Vitamin C intake provides evidence to suggest that reducing the common colds in Korean Army soldiers. Our results may serve as a basis for introducing military healthcare policies that can provide vitamin C supplementation for military personnel in basic military training.
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Affiliation(s)
- Tae Kyung Kim
- Department of Public Health, Yonsei University, Seoul, South Korea .,Department of Health policy & Management, Armed Forces Medical Command, Seongnam, South Korea
| | - H R Lim
- Department of Clinical Medicine, Armed Forces Medical School, Daejeon, South Korea
| | - J S Byun
- Department of Inspection, Armed Forces Medical Command, Seongnam, South Korea
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Abstract
In the early literature, vitamin C deficiency was associated with pneumonia. After its identification, a number of studies investigated the effects of vitamin C on diverse infections. A total of 148 animal studies indicated that vitamin C may alleviate or prevent infections caused by bacteria, viruses, and protozoa. The most extensively studied human infection is the common cold. Vitamin C administration does not decrease the average incidence of colds in the general population, yet it halved the number of colds in physically active people. Regularly administered vitamin C has shortened the duration of colds, indicating a biological effect. However, the role of vitamin C in common cold treatment is unclear. Two controlled trials found a statistically significant dose-response, for the duration of common cold symptoms, with up to 6-8 g/day of vitamin C. Thus, the negative findings of some therapeutic common cold studies might be explained by the low doses of 3-4 g/day of vitamin C. Three controlled trials found that vitamin C prevented pneumonia. Two controlled trials found a treatment benefit of vitamin C for pneumonia patients. One controlled trial reported treatment benefits for tetanus patients. The effects of vitamin C against infections should be investigated further.
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Affiliation(s)
- Harri Hemilä
- Department of Public Health, University of Helsinki, Helsinki FI-00014, Finland.
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Mitmesser SH, Ye Q, Evans M, Combs M. Determination of plasma and leukocyte vitamin C concentrations in a randomized, double-blind, placebo-controlled trial with Ester-C(®). SPRINGERPLUS 2016; 5:1161. [PMID: 27512620 PMCID: PMC4960105 DOI: 10.1186/s40064-016-2605-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 06/16/2016] [Indexed: 01/21/2023]
Abstract
Background Rapid uptake of vitamin C into blood and retention in tissues are important indicators of the efficacy of vitamin C supplementation and its immune-supporting role. The objective of this study was to evaluate the bioavailability of vitamin C in plasma (reflective of recent intake) and leukocytes (reflective of tissue stores and influences on immune function) from a novel vitamin C formulation, Ester-C®. Methods The study was a double-blind, placebo-controlled, crossover trial. Thirty-six subjects, 18–60 years of age, were randomized to receive placebo (PL, 0 mg vitamin C), ascorbic acid (AA, 1000 mg vitamin C), and Ester-C® (EC, 1000 mg vitamin C). Plasma and leukocyte vitamin C were measured baseline and at 2, 4, 8 and 24 h postdose. Results The concentration and percent change from baseline in plasma were significantly higher with EC at all time points when compared to PL. No significant differences between EC and AA were observed in plasma concentration. Maximum plasma concentration was higher for EC compared to AA (P = 0.039) and PL (P < 0.001). Plasma area under the curve (AUC0–24h) was higher for EC (P < 0.001) compared to PL. The concentration change from baseline in leukocyte vitamin C was increased with EC at 24 h post-dose (P = 0.036) while no significant within-group changes were observed in AA or PL at any time point. The percent change in leukocyte vitamin C concentration was higher for EC at 8 and 24 h compared to AA (P = 0.028 and P = 0.034, respectively) and PL (P = 0.042 and P = 0.036, respectively). Conclusions A single dose of EC resulted in favorable percent change in leukocyte vitamin C concentration compared to AA and PL, indicating EC is retained longer within leukocytes. Trial registration ClinicalTrials.gov Identifier NCT01852903
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Affiliation(s)
- Susan H Mitmesser
- Department of Nutrition & Scientific Affairs, NBTY, Inc., Ronkonkoma, NY 11779 USA
| | - Qian Ye
- Department of Nutrition & Scientific Affairs, NBTY, Inc., Ronkonkoma, NY 11779 USA
| | - Mal Evans
- KGK Synergize, Suite 1440, One London Place 255 Queens Avenue, London, ON N6A 5R8 Canada
| | - Maile Combs
- Department of Nutrition & Scientific Affairs, NBTY, Inc., Ronkonkoma, NY 11779 USA
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High dietary intake of vitamin C suppresses age-related thymic atrophy and contributes to the maintenance of immune cells in vitamin C-deficient senescence marker protein-30 knockout mice. Br J Nutr 2015; 113:603-9. [PMID: 25608928 DOI: 10.1017/s0007114514003857] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Vitamin C (VC) is an essential nutrient for humans and certain other animals. It has antioxidant properties and has been reported to ameliorate oxidative damage to lipids, DNA and proteins. However, the effects of VC on immune function are poorly understood, especially the influence of long-term high-dose VC intake on the number and function of immune cells. In the present study, to evaluate the immune effects of VC, VC-deficient senescence marker protein-30 knockout (SMP30KO) mice were fed a diet containing the recommended level of VC (20 mg/kg per d; 0·02 % VC) or a high level of VC (200 mg/kg per d; 0·2 % VC) for 1 year. The plasma VC concentration of the 0·02 % group was the same as that of age-matched C57BL/6 mice after 1 year of feeding; however, plasma VC concentration and thymus weight were significantly higher in the 0·2 % VC group than in the 0·02 % VC group. The total counts of leucocytes, lymphocytes, granulocytes and monocytes in the peripheral blood, as well as the number of splenocytes and thymocytes, were all significantly higher in the 0·2 % VC group than in the 0·02 % VC group. In addition, the number of naive T cells in peripheral blood lymphocytes, the number of memory T-cell populations in splenocytes, and the number of cluster of differentiation (CD)4⁺CD8⁺ or CD4⁺CD8⁻ or CD4⁻CD8⁺ T cells in thymocytes were all markedly higher in the 0·2 % VC group than in the 0·02 % VC group after 1 year of dietary treatment. These results suggest that a long-term high-dose intake of VC is effective in the maintenance of immune cells, partly through the suppression of age-related thymic involution in VC-deficient SMP30KO mice.
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Talbott SM, Talbott JA. Baker's yeast beta-glucan supplement reduces upper respiratory symptoms and improves mood state in stressed women. J Am Coll Nutr 2013; 31:295-300. [PMID: 23378458 DOI: 10.1080/07315724.2012.10720441] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Several studies have shown a baker's yeast beta-1,3/1,6-d-glucan, extracted from Saccharomyces cerevisiae, is effective in reducing the incidence of cold and flu symptoms. This study evaluated the effect of a specific beta-glucan supplement (Wellmune) on upper respiratory tract symptoms and psychological well-being in women with moderate levels of psychological stress. METHODS Healthy women (38 ± 12 years old) prescreened for moderate levels of psychological stress, self-administered a placebo (n = 38) or 250 mg of Wellmune (n = 39) daily for 12 weeks. We used the Profile of Mood States (POMS) psychological survey to assess changes in mental/physical energy levels (vigor) and overall well-being (global mood state). A quantitative health perception log was used to track upper respiratory symptoms. RESULTS Subjects in the Wellmune group reported fewer upper respiratory symptoms compared to placebo (10% vs 29%), better overall well-being (global mood state: 99 ± 19 vs 108 ± 23, p < 0.05), and superior mental/physical energy levels (vigor: 19.9 ± 4.7 vs 15.8 ± 6.3, p < 0.05). CONCLUSIONS These data show that daily dietary supplementation with Wellmune reduces upper respiratory symptoms and improves mood state in stressed subjects, and thus it may be a useful approach for maintaining immune protection against daily stressors.
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Abstract
BACKGROUND Vitamin C (ascorbic acid) for preventing and treating the common cold has been a subject of controversy for 70 years. OBJECTIVES To find out whether vitamin C reduces the incidence, the duration or severity of the common cold when used either as a continuous regular supplementation every day or as a therapy at the onset of cold symptoms. SEARCH METHODS We searched CENTRAL 2012, Issue 11, MEDLINE (1966 to November week 3, 2012), EMBASE (1990 to November 2012), CINAHL (January 2010 to November 2012), LILACS (January 2010 to November 2012) and Web of Science (January 2010 to November 2012). We also searched the U.S. National Institutes of Health trials register and WHO ICTRP on 29 November 2012. SELECTION CRITERIA We excluded trials which used less than 0.2 g per day of vitamin C and trials without a placebo comparison. We restricted our review to placebo-controlled trials. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data. We assessed 'incidence' of colds during regular supplementation as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean number of days of illness of cold episodes. MAIN RESULTS Twenty-nine trial comparisons involving 11,306 participants contributed to the meta-analysis on the risk ratio (RR) of developing a cold whilst taking vitamin C regularly over the study period. In the general community trials involving 10,708 participants, the pooled RR was 0.97 (95% confidence interval (CI) 0.94 to 1.00). Five trials involving a total of 598 marathon runners, skiers and soldiers on subarctic exercises yielded a pooled RR of 0.48 (95% CI 0.35 to 0.64).Thirty-one comparisons examined the effect of regular vitamin C on common cold duration (9745 episodes). In adults the duration of colds was reduced by 8% (3% to 12%) and in children by 14% (7% to 21%). In children, 1 to 2 g/day vitamin C shortened colds by 18%. The severity of colds was also reduced by regular vitamin C administration.Seven comparisons examined the effect of therapeutic vitamin C (3249 episodes). No consistent effect of vitamin C was seen on the duration or severity of colds in the therapeutic trials.The majority of included trials were randomised, double-blind trials. The exclusion of trials that were either not randomised or not double-blind had no effect on the conclusions. AUTHORS' CONCLUSIONS The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise. Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them. Further therapeutic RCTs are warranted.
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Affiliation(s)
- Harri Hemilä
- Department of Public Health, POB 41, University of Helsinki, Helsinki, Finland.
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Ouchi E, Niu K, Kobayashi Y, Guan L, Momma H, Guo H, Chujo M, Otomo A, Cui Y, Nagatomi R. Frequent alcohol drinking is associated with lower prevalence of self-reported common cold: a retrospective study. BMC Public Health 2012; 12:987. [PMID: 23158193 PMCID: PMC3533961 DOI: 10.1186/1471-2458-12-987] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 11/13/2012] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Alcohol intake has been associated with reduced incidence of common cold symptoms in 2 European studies. However, no study has addressed the association between the frequency of alcohol intake and the incidence of common cold. This study aimed to investigate the association between the amount and frequency of alcohol drinking and the retrospective prevalence of common cold in Japanese men. METHODS This retrospective study included men who participated in an annual health examination conducted in Sendai, Japan. The frequency of common cold episodes in the previous year was self-reported. The weekly frequency and amount of alcohol consumed, as well as the type of alcoholic drink, were reported by a brief-type self-administered diet history questionnaire. Logistic regression models were used to analyze the association between the amount and frequency of alcohol intake and the retrospective prevalence of common cold. RESULTS Among 899 men, 83.4% of the subjects reported drinking alcohol, and 55.4% of the subjects reported having experienced at least one episode of common cold in the previous year. Compared with non-drinkers, the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for having had 1 or more episodes of common cold during the past year across categories of alcohol intake frequency of 3 or less, 4-6, and 7 days/week were 0.827 (0.541-1.266), 0.703 (0.439-1.124), and 0.621 (0.400-0.965), respectively (P for trend = 0.025); the adjusted ORs with 95% CIs for having had of 2 or more episodes of common cold across the same categories were 0.642 (0.395-1.045), 0.557 (0.319-0.973), and 0.461 (0.270-0.787), respectively (P for trend = 0.006). Compared with subjects who consumed 11.5-35.8 g of alcohol per day, the non-drinkers were significantly more likely to experience 2 or more episodes of common cold (OR, 1.843; 95% CI, 1.115-3.047). CONCLUSION The frequency, not the amount, of alcohol intake was significantly related to lower prevalence of self-reported common cold episodes in Japanese men.
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Affiliation(s)
- Eriko Ouchi
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Kaijun Niu
- Division of Biomedical Engineering for Health & Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, 980-8575, Japan
- Lab of Nutritional Epidemiology, Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, 300070, People’s Republic of China
| | - Yoritoshi Kobayashi
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Lei Guan
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Haruki Momma
- Division of Biomedical Engineering for Health & Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, 980-8575, Japan
| | - Hui Guo
- Division of Biomedical Engineering for Health & Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, 980-8575, Japan
| | - Masahiko Chujo
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Atsushi Otomo
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Yufei Cui
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Ryoichi Nagatomi
- Department of Medicine & Science in Sports & Exercise, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
- Division of Biomedical Engineering for Health & Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, 980-8575, Japan
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Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev 2012; 2012:CD007176. [PMID: 22419320 PMCID: PMC8407395 DOI: 10.1002/14651858.cd007176.pub2] [Citation(s) in RCA: 284] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Our systematic review has demonstrated that antioxidant supplements may increase mortality. We have now updated this review. OBJECTIVES To assess the beneficial and harmful effects of antioxidant supplements for prevention of mortality in adults. SEARCH METHODS We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to February 2011. We scanned bibliographies of relevant publications and asked pharmaceutical companies for additional trials. SELECTION CRITERIA We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. DATA COLLECTION AND ANALYSIS Three authors extracted data. Random-effects and fixed-effect model meta-analyses were conducted. Risk of bias was considered in order to minimise the risk of systematic errors. Trial sequential analyses were conducted to minimise the risk of random errors. Random-effects model meta-regression analyses were performed to assess sources of intertrial heterogeneity. MAIN RESULTS Seventy-eight randomised trials with 296,707 participants were included. Fifty-six trials including 244,056 participants had low risk of bias. Twenty-six trials included 215,900 healthy participants. Fifty-two trials included 80,807 participants with various diseases in a stable phase. The mean age was 63 years (range 18 to 103 years). The mean proportion of women was 46%. Of the 78 trials, 46 used the parallel-group design, 30 the factorial design, and 2 the cross-over design. All antioxidants were administered orally, either alone or in combination with vitamins, minerals, or other interventions. The duration of supplementation varied from 28 days to 12 years (mean duration 3 years; median duration 2 years). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (21,484 dead/183,749 (11.7%) versus 11,479 dead/112,958 (10.2%); 78 trials, relative risk (RR) 1.02, 95% confidence interval (CI) 0.98 to 1.05) but significantly increased mortality in a fixed-effect model (RR 1.03, 95% CI 1.01 to 1.05). Heterogeneity was low with an I(2)- of 12%. In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. Meta-regression analysis did not find a significant difference in the estimated intervention effect in the primary prevention and the secondary prevention trials. In the 56 trials with a low risk of bias, the antioxidant supplements significantly increased mortality (18,833 dead/146,320 (12.9%) versus 10,320 dead/97,736 (10.6%); RR 1.04, 95% CI 1.01 to 1.07). This effect was confirmed by trial sequential analysis. Excluding factorial trials with potential confounding showed that 38 trials with low risk of bias demonstrated a significant increase in mortality (2822 dead/26,903 (10.5%) versus 2473 dead/26,052 (9.5%); RR 1.10, 95% CI 1.05 to 1.15). In trials with low risk of bias, beta-carotene (13,202 dead/96,003 (13.8%) versus 8556 dead/77,003 (11.1%); 26 trials, RR 1.05, 95% CI 1.01 to 1.09) and vitamin E (11,689 dead/97,523 (12.0%) versus 7561 dead/73,721 (10.3%); 46 trials, RR 1.03, 95% CI 1.00 to 1.05) significantly increased mortality, whereas vitamin A (3444 dead/24,596 (14.0%) versus 2249 dead/16,548 (13.6%); 12 trials, RR 1.07, 95% CI 0.97 to 1.18), vitamin C (3637 dead/36,659 (9.9%) versus 2717 dead/29,283 (9.3%); 29 trials, RR 1.02, 95% CI 0.98 to 1.07), and selenium (2670 dead/39,779 (6.7%) versus 1468 dead/22,961 (6.4%); 17 trials, RR 0.97, 95% CI 0.91 to 1.03) did not significantly affect mortality. In univariate meta-regression analysis, the dose of vitamin A was significantly associated with increased mortality (RR 1.0006, 95% CI 1.0002 to 1.001, P = 0.002). AUTHORS' CONCLUSIONS We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.
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Affiliation(s)
- Goran Bjelakovic
- Department of InternalMedicine,Medical Faculty, University ofNis,Nis, Serbia.
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17
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Mathes A, Bellanger R. Herbs and other dietary supplements: current regulations and recommendations for use to maintain health in the management of the common cold or other related infectious respiratory illnesses. J Pharm Pract 2011; 23:117-27. [PMID: 21507804 DOI: 10.1177/0897190009358711] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Herbal preparations are sold as dietary supplements in the United States and are subject to the rules and regulations of various health care and economic government agencies that monitor the sale of these products. One approach to assessing the usefulness of these substances is to focus on one particular disease state and then review both the primary literature and expert opinion. The common cold is an important illness due to its recurring nature, the number of people it afflicts, and its economic impact on patients. Dietary supplements have been shown to decrease the duration, the severity, and the frequency of symptoms of the common cold. The most commonly available supplements are zinc, ginseng, echinacea, and vitamin C. Data from expert opinion suggested that certain supplements are more beneficial than others to maintain one's health during episodes of the common cold. Expert opinion regarding the use of dietary supplements in other related infectious respiratory illnesses, such as the flu, when aggregated with expert opinion findings regarding the common cold were not contradictory. The primary literature provided insights into specific dosages and compounds that may be used in practice.
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Affiliation(s)
- Angelo Mathes
- Consultation Angelo Inc, Town of Mount Royal, QC, Canada.
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19
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Abstract
Vitamin C functions in enzyme activation, oxidative stress reduction, and immune function. There is considerable evidence that vitamin C protects against respiratory tract infections and reduces risk for cardiovascular disease and some cancers. Current trials are examining the efficacy of intravenous vitamin C as cancer therapy. Many experts believe that the recommended intakes for vitamin C (45 to 90 mg daily) are several orders of magnitude too low to support optimal vitamin C functionality. Also, there is a misperception that vitamin C deficiency disease (scurvy) is largely historical and rarely observed in developed nations. Physical symptoms of scurvy include swelling of the lower extremities, bleeding gums, fatigue, and hemorrhaging, as well as psychological problems, including depression, hysteria, and social introversion. The long-term safety of vitamin C supplementation seems evident as large investigations have noted reduced risk of mortality in vitamin C supplementing populations and in those with elevated plasma vitamin C concentrations.
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Kurihara S, Hiraoka T, Akutsu M, Sukegawa E, Bannai M, Shibahara S. Effects of (L)-cystine and (L)-theanine supplementation on the common cold: a randomized, double-blind, and placebo-controlled trial. JOURNAL OF AMINO ACIDS 2010; 2010:307475. [PMID: 22331996 PMCID: PMC3275984 DOI: 10.4061/2010/307475] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 02/25/2010] [Indexed: 11/23/2022]
Abstract
The common cold is one of the most frequent illnesses caused by viral infection. Recently, we have reported that oral administration of cystine and theanine (CT) to mice enhanced the humoral immune response associated with antibody production. Based on this mouse study, we investigated the effects of CT supplementation on the common cold in humans as a pilot study. A total of 176 healthy male volunteers were randomized to receive either placebo or CT (490 mg) tablets twice daily for 35 days. The incidence outcome was assessed using the definition in our laboratory based on questionnaires regarding cold symptoms. The incidence of subjects with colds during the trial was significantly lower in the CT group than in the placebo group, although the duration of the colds was not significantly different between the groups. These results suggest that CT supplementation may be useful for the prevention of the common cold.
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Affiliation(s)
- Shigekazu Kurihara
- Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Kanagawa 210-8681, Japan
| | - Takenori Hiraoka
- Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Kanagawa 210-8681, Japan
| | - Masahisa Akutsu
- Wellness Promotion Center, Ajinomoto Co., Inc., Kanagawa 210-8681, Japan
| | - Eiji Sukegawa
- Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Kanagawa 210-8681, Japan
| | - Makoto Bannai
- Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Kanagawa 210-8681, Japan
| | - Susumu Shibahara
- Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Kanagawa 210-8681, Japan
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21
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Douglas RM, Hemilä H, Chalker E, Treacy B. Cochrane review: Vitamin C for preventing and treating the common cold. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/ebch.266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev 2008:CD007176. [PMID: 18425980 DOI: 10.1002/14651858.cd007176] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival. OBJECTIVES To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials. SEARCH STRATEGY We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials. SELECTION CRITERIA We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials). DATA COLLECTION AND ANALYSIS Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity. MAIN RESULTS Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09). AUTHORS' CONCLUSIONS We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.
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Affiliation(s)
- G Bjelakovic
- Copenhagen University Hospital, Rigshospitalet, Department 3344,Copenhagen Trial Unit, Centre for Clinical Intervention Research, Blegdamsvej 9, Copenhagen, Denmark, DK-2100.
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Abstract
BACKGROUND The role of vitamin C (ascorbic acid) in the prevention and treatment of the common cold has been a subject of controversy for 60 years, but is widely sold and used as both a preventive and therapeutic agent. OBJECTIVES To discover whether oral doses of 0.2 g or more daily of vitamin C reduces the incidence, duration or severity of the common cold when used either as continuous prophylaxis or after the onset of symptoms. SEARCH STRATEGY We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2006); MEDLINE (1966 to December 2006); and EMBASE (1990 to December 2006). SELECTION CRITERIA Papers were excluded if a dose less than 0.2 g per day of vitamin C was used, or if there was no placebo comparison. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data and assessed trial quality. 'Incidence' of colds during prophylaxis was assessed as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean days of illness of cold episodes. MAIN RESULTS Thirty trial comparisons involving 11,350 study participants contributed to the meta-analysis on the relative risk (RR) of developing a cold whilst taking prophylactic vitamin C. The pooled RR was 0.96 (95% confidence intervals (CI) 0.92 to 1.00). A subgroup of six trials involving a total of 642 marathon runners, skiers, and soldiers on sub-arctic exercises reported a pooled RR of 0.50 (95% CI 0.38 to 0.66). Thirty comparisons involving 9676 respiratory episodes contributed to a meta-analysis on common cold duration during prophylaxis. A consistent benefit was observed, representing a reduction in cold duration of 8% (95% CI 3% to 13%) for adults and 13.6% (95% CI 5% to 22%) for children. Seven trial comparisons involving 3294 respiratory episodes contributed to the meta-analysis of cold duration during therapy with vitamin C initiated after the onset of symptoms. No significant differences from placebo were seen. Four trial comparisons involving 2753 respiratory episodes contributed to the meta-analysis of cold severity during therapy and no significant differences from placebo were seen. AUTHORS' CONCLUSIONS The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence suggests that it could be justified in people exposed to brief periods of severe physical exercise or cold environments.
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Moyad MA, Combs MA. Vitamin C Dietary Supplements: An Objective Review of the Clinical Evidence. Part I. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.spre.2007.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Gruenwald J, Graubaum HJ, Busch R, Bentley C. Safety and tolerance of ester-C compared with regular ascorbic acid. Adv Ther 2006; 23:171-8. [PMID: 16644619 DOI: 10.1007/bf02850358] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The goal of this randomized, double-blind crossover clinical trial in 50 healthy volunteers sensitive to acidic foods was to evaluate whether Ester-C calcium ascorbate causes fewer epigastric adverse effects than are produced by regular ascorbic acid (AA). Volunteers were randomly separated into 2 groups of 25. The study comprised an observation period of 9 days (phase 1 medication for 3 consecutive days, washout phase for 3 consecutive days, phase 2 medication for 3 consecutive days). Participants took 1000 mg vitamin C as Ester-C during phase 1 of the study followed by 1000 mg of vitamin C as AA during phase 2, or vice versa. During the course of the study, 3 examinations for the evaluation of epigastric adverse effects were performed (on days 0, 3, and 9). Participants used a diary to record epigastric adverse effects on a daily basis. In total, 28 (56%) of 50 participants reported 88 epigastric adverse effects of mild to moderate intensity. Of these 88 adverse effects, 33 (37.5%) occurred after intake of Ester-C and 55 (62.5%) were noted after intake of AA. The tolerability of Ester-C was rated "very good" by 72% of participants, whereas AA was rated "very good" by only 54%. This difference is statistically significant (P<.05). Investigators concluded that Ester-C compared with AA caused significantly fewer epigastric adverse effects in participants sensitive to acidic foods and that Ester-C is much better tolerated.
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The vitamin mystique: an analysis of beliefs and reputations of vitamin supplements among a regional sample of grocery shoppers. Food Qual Prefer 2005. [DOI: 10.1016/j.foodqual.2004.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Douglas RM, Hemila H, D'Souza R, Chalker EB, Treacy B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev 2004:CD000980. [PMID: 15495002 DOI: 10.1002/14651858.cd000980.pub2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The role of oral vitamin C (ascorbic acid) in the prevention and treatment of the common cold has been a subject of controversy for at least sixty years. Public interest in the topic continues to be high and vitamin C continues to be widely sold and used as a preventive and therapeutic agent for this common ailment. OBJECTIVES To discover whether oral vitamin C in doses of 200 mg or more daily, reduces the incidence, duration or severity of the common cold when used either as continuous prophylaxis or after the onset of cold symptoms. SEARCH STRATEGY This updated review added to earlier searches, a full search of the following electronic databases: the Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2004); MEDLINE (January 1966 to June 2004); and EMBASE (1990 to June 2004). SELECTION CRITERIA Papers were excluded if a dose less than 200 mg daily of vitamin C was used; if there was no placebo comparison; if methods of outcome assessment were inadequately described; and if the report did not record any of the three study outcomes (incidence, duration or severity) in sufficient detail to enter into the meta-analysis. Three criteria of study quality were assessed: Jadad scores, placebo distinguish-ability, and allocation concealment. DATA COLLECTION AND ANALYSIS Two reviewers independently extracted data and assessed trial quality. 'Incidence' of colds during prophylaxis was assessed as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean days of illness of cold episodes and 'severity' of these episodes was assessed by days confined indoors, off work or school. or by symptom severity scores. MAIN RESULTS Twenty-nine trial comparisons involving 11,077 study participants contributed to the meta-analysis on the relative risk (RR) of developing a cold while taking prophylaxis. The pooled RR was 0.96 (95% CI 0.92 to 1.00). A subgroup of six trials that involved a total of 642 marathon runners, skiers, and soldiers on sub-arctic exercises reported a pooled RR of 0.50 (95%CI 0.38 to 0.66). Thirty comparisons that involved 9,676 respiratory episodes contributed to the meta-analysis on common cold duration during prophylaxis . A consistent benefit was observed, representing a reduction in cold duration of 8% (95% CI 3% to 13%) for adult participants and 13.5% (95% CI 5% to 21%) for child participants. Fifteen trial comparisons that involved 7,045 respiratory episodes contributed to the meta-analysis of severity of episodes experienced while on prophylaxis. The pooled results revealed a difference favouring those on vitamin C when days confined to home and off work or school were taken as a measure of severity (p = 0.02), and when restricting to studies which used symptom severity scores (p = 0.16), and for the both measures of severity combined (p = 0.004). Seven trial comparisons that involved 3,294 respiratory episodes contributed to the meta-analysis of cold duration during therapy with vitamin C that was initiated after the onset of cold symptoms, and no significant difference from placebo was seen. Four trial comparisons that involved 2,753 respiratory episodes, contributed to the meta-analysis of cold severity during therapy and no significant difference from placebo was seen.In laboratory studies, differing methods of artificial transmission of virus to vitamin C or placebo treated volunteers in residential experiments gave different results. Volunteers infected by nasal installation showed small or no benefit from vitamin C, whereas a group who were infected more naturally, reported less severe symptom severity scores (p = 0.04). REVIEWERS' CONCLUSIONS The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence shows that it could be justified in persons exposed to brief periods of severe physical exercise and/or cold environments. Also, the consistent and statistically significant small benefits on duration and severity for those using regular vitamin C prophylaxis indicates that vitamin C plays some role in respiratory defence mechanisms. The trials in which vitamin C was introduced at the onset of colds as therapy did not show any benefit in doses up to 4 grams daily, but one large trial reported equivocal benefit from an 8 gram therapeutic dose at onset of symptoms.
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Affiliation(s)
- R M Douglas
- National Centre for Epidemiology and Population Health, Australian National University, 34 Nungara Place, Aranda, ACT, Australia, 2614
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Rohde G, Schultze-Werninghaus G, Bauer TT. [Treatment for viral respiratory infections: Principles of action, strategies, and future prospects]. Internist (Berl) 2004; 45:468-75. [PMID: 15021931 PMCID: PMC7079889 DOI: 10.1007/s00108-003-1111-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pulmonary viral infections are associated with substantial morbidity and socioeconomic costs. Rhinovirus, influenza A and B, adenovirus, parainfluenza, respiratory syncytial virus (RSV), and coronavirus are etiologies most often associated with infections of the upper and lower respiratory tract. Therapy of viral infections in nonimmunocompromised hosts has only developed slowly during recent years, despite the enormous socioeconomic impact. This is in part due to the complex virus/host interactions and numerous and varying mechanisms of infection. Neuraminidase inhibitors have produced notable progress in the therapeutic approaches to influenza-associated pulmonary infections and are at least able to shorten the duration of symptoms in selected patients. However, neuraminidase inhibitors can only be applied in specific infections and the spectrum of agents with antiviral activity is broad. This article summarizes major principles of antiviral efficacy and reviews recent clinical trials.
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Affiliation(s)
- G Rohde
- Medizinische Klinik III, Berufsgenossenschaftliche Kliniken Bergmannsheil, Klinikum der Ruhr-Universität Bochum.
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