Vitamin C for preventing and treating the common cold

Plant-based diet and COVID-19 severity: results from a cross-sectional study

Although previous findings have shown the beneficial role of healthy eating pattern on the human immune system, the association between plant-based diet and COVID-19 severity has not yet been elucidated. This study aimed to determine the possible role of plant-based diet index (PDI) in COVID-19 severity. This cross-sectional, multicentral study was conducted on 141 patients with confirmed COVID-19. Dietary intakes of the patients were evaluated using a validated food frequency questionnaire. Then, PDI was compared between patients who needed to be hospitalised (considered severe cases), and those who got treatment at home (considered non-severe cases). After adjustment for confounders including age, sex, energy intake and body mass index, lower odds of hospitalisation were found for participants having a greater score of overall PDI (OR per 10 units increase: 0.42; 95% CI 0.22 to 0.80) and healthy PDI (OR per 10 unit increase: 0.45; 95% CI 0.26 to 0.78). In conclusion, our data presented that there is a relation between PDI and lower risk of hospitalisation in COVID-19 patients, possibly through boosting the immune function.

Dietary supplements to reduce symptom severity and duration in people with SARS-CoV-2: a double-blind randomised controlled trial

BACKGROUND

COVID-19 has caused morbidity, hospitalisation and mortality worldwide. Despite effective vaccines, there is still a need for effective treatments, especially for people in the community. Dietary supplements have long been used to treat respiratory infections, and preliminary evidence indicates some may be effective in people with COVID-19. We sought to evaluate whether a combination of vitamin C, vitamin D3, vitamin K2 and zinc could improve overall health and decrease symptom burden in outpatients diagnosed with COVID-19.

METHODS

Participants were randomised to receive either vitamin C (6 g), vitamin D3 (1000 units), vitamin K2 (240 μg) and zinc acetate (75 mg) or placebo daily for 21 days and were followed for 12 weeks. An additional loading dose of 50 000 units vitamin D3 (or placebo) was given on day one. The primary outcome was participant-reported overall health using the EuroQol Visual Assessment Scale summed over 21 days. Secondary outcomes included health status, symptom severity, symptom duration, delayed return to usual health, frequency of hospitalisation and mortality.

RESULTS

90 patients (46 control, 44 treatment) were randomised. The study was stopped prematurely due to insufficient capacity for recruitment. The mean difference (control-treatment) in cumulative overall health was -37.4 (95% CI -157.2 to 82.3), p=0.53 on a scale of 0-2100. No clinically or statistically significant differences were seen in any secondary outcomes.

INTERPRETATION

In this double-blind, placebo-controlled, randomised trial of outpatients diagnosed with COVID-19, the dietary supplements vitamin C, vitamin D3, vitamin K2 and zinc acetate showed no clinically or statistically significant effects on the documented measures of health compared with a placebo when given for 21 days. Termination due to feasibility limited our ability to demonstrate the efficacy of these supplements for COVID-19. Further research is needed to determine clinical utility.

TRIAL REGISTRATION NUMBER

NCT04780061.

The Role of Vitamin C in Human Immunity and Its Treatment Potential Against COVID-19: A Review Article

The outbreak of the COVID-19 pandemic has left clinicians around the world searching for viable prevention and treatment options to use against the virus. The important physiologic properties of vitamin C have been well documented regarding its use by immune cells and its role as an antioxidant. It has previously shown potential as a prophylactic and treatment option for other respiratory viruses, and because of this, there has been intrigue into whether these positive outcomes translate into a cost-effective prevention and treatment option for COVID-19. To this point, there have only been a few clinical trials performed to assess the validity of this notion, with very few showing definitive positive outcomes when vitamin C has been incorporated into prophylactic or treatment protocols to use against coronavirus. When being used to specifically treat the severe complications that arise from COVID-19, vitamin C is a reliable option to treat COVID-19-induced sepsis but not pneumonia or acute respiratory distress syndrome (ARDS). As a treatment option, high-dose therapy has shown flashes of promise in a few studies although investigators in these studies often subject the testing group to multimodal therapies that include vitamin C as opposed to just vitamin C alone. Given the role that vitamin C has shown to uphold regarding the human immune response, it is currently advised for all individuals to maintain a normal physiologic range of plasma vitamin C through diet or supplements for adequate prophylactic protection against the virus. More research with definitive outcomes will be needed before it is recommended to provide high-dose vitamin C therapy to prevent or treat COVID-19.

Prevention of New Respiratory Episodes in Children with Recurrent Respiratory Infections: An Expert Consensus Statement

In healthy infants and young children, the development of respiratory tract infections (RTIs) is extremely common. In this paper, we present an international consensus of the available approaches for the prevention of recurrent RTIs in children, including the atopic/allergic ones as well as those with asthma. Few convincing measures for reducing the frequency and clinical relevance of recurrent respiratory episodes in RTI-prone children have been developed until now. Among the most recently suggested measures, immunotherapy is attractive, but only for OM-85 is there a sufficient number of well-conducted clinical trials confirming efficacy in RTIs prevention with an adequate safety profile. In the case of probiotics, it is not clear which bacteria can offer the best results and which dosage and schedule of administration are the most effective. The problems of dosage and the schedule of administration are not solved also for vitamin D, despite some promising efficacy results. While we wait for new knowledge, the elimination or reduction as much as possible of the environmental factors that favor RTIs, vaccination when available and/or indicated, and the systematic application of the traditional methods for infection prevention, such as hand washing, remain the best measures to prevent recurrent infections in RTI-prone children.

L-Ascorbic Acid Inhibits Breast Cancer Growth by Inducing IRE/JNK/CHOP-Related Endoplasmic Reticulum Stress-Mediated p62/SQSTM1 Accumulation in the Nucleus

Anticancer effects of L-ascorbic acid (Vitamin C, L-AA) have been reported in various types of cancers. L-AA intake reduces breast cancer recurrence and mortality; however, the role of L-AA in the treatment of breast cancer remains poorly understood. In this study, we investigated the effect and mechanism action of L-AA on breast cancer growth. L-AA inhibited the growth of breast cancer cells by inducing apoptotic cell death at the evaluated treatment concentrations without affecting normal cells. Moreover, L-AA induces autophagosome formation via regulation of mammalian target of rapamycin (mTOR), Beclin1, and autophagy-related genes (ATGs) and increased autophagic flux. Notably, we observed that L-AA increased p62/SQSTM1 (sequestosome 1) protein levels. Accumulation of p62 protein in cancer cells in response to stress has been reported, but its role in cancer regulation remains controversial. Here, we demonstrated that L-AA-induced p62 accumulation is related to L-AA-induced breast cancer growth inhibition. Furthermore, L-AA induced endoplasmic reticulum (ER) stress via the IRE–JNK–CHOP (inositol-requiring endonuclease–c-Jun N-terminal kinase–C/EBP homologous protein) signaling pathways, which increased the nuclear levels of p62/SQSTM1. These findings provide evidence that L-AA-induced ER stress could be crucial for p62 accumulation-dependent cell death, and L-AA can be useful in breast cancer treatment.

Plasma concentrations of ascorbic acid in a cross section of the German population

Objectives Vitamin C deficiency is considered extremely rare in modern industrialized countries. This study was performed to assess vitamin C concentrations in the German population. Methods As part of a consultant-patient seminar on nutrition and food intolerances, patients were asked to participate in this study on a voluntary basis. Blood samples were taken for analysis of serum vitamin C concentrations, and all patients were asked to complete a questionnaire. The vitamin C concentration was determined by high-performance liquid chromatography. Results Of approximately 300 patients attending the seminar, 188 (62.6%) consented to vitamin C blood sample analysis and 178 (59.3%) answered the questionnaire. The mean vitamin C concentration was 7.98 mg/L (range, 0.50-17.40; reference range, 5-15 mg/L). A low plasma level with vitamin C insufficiency (<5 mg/L) was found in 31 patients (17.4%), and a potential scorbutogenic deficiency (<1.5 mg/L) was found in 6 (3.3%). Conclusions Potential vitamin C insufficiency and deficiency is common. It is therefore possible, even in modern developed populations, that certain individuals may require a higher intake of vitamin C.

Duration of the common cold and similar continuous outcomes should be analyzed on the relative scale: a case study of two zinc lozenge trials

BACKGROUND

The relative scale has been used for decades in analysing binary data in epidemiology. In contrast, there has been a long tradition of carrying out meta-analyses of continuous outcomes on the absolute, original measurement, scale. The biological rationale for using the relative scale in the analysis of binary outcomes is that it adjusts for baseline variations; however, similar baseline variations can occur in continuous outcomes and relative effect scale may therefore be often useful also for continuous outcomes. The aim of this study was to determine whether the relative scale is more consistent with empirical data on treating the common cold than the absolute scale.

METHODS

Individual patient data was available for 2 randomized trials on zinc lozenges for the treatment of the common cold. Mossad (Ann Intern Med 125:81-8, 1996) found 4.0 days and 43% reduction, and Petrus (Curr Ther Res 59:595-607, 1998) found 1.77 days and 25% reduction, in the duration of colds. In both trials, variance in the placebo group was significantly greater than in the zinc lozenge group. The effect estimates were applied to the common cold distributions of the placebo groups, and the resulting distributions were compared with the actual zinc lozenge group distributions.

RESULTS

When the absolute effect estimates, 4.0 and 1.77 days, were applied to the placebo group common cold distributions, negative and zero (i.e., impossible) cold durations were predicted, and the high level variance remained. In contrast, when the relative effect estimates, 43 and 25%, were applied, impossible common cold durations were not predicted in the placebo groups, and the cold distributions became similar to those of the zinc lozenge groups.

CONCLUSIONS

For some continuous outcomes, such as the duration of illness and the duration of hospital stay, the relative scale leads to a more informative statistical analysis and more effective communication of the study findings. The transformation of continuous data to the relative scale is simple with a spreadsheet program, after which the relative scale data can be analysed using standard meta-analysis software. The option for the analysis of relative effects of continuous outcomes directly from the original data should be implemented in standard meta-analysis programs.

Vitamins, Are They Safe?

The consumption of a daily multivitamin among people all over the world is dramatically increasing in recent years. Most of the people believe that if vitamins are not effective, at least they are safe. However, the long term health consequences of vitamins consumption are unknown. This study aimed to assess the side effects and possible harmful and detrimental properties of vitamins and to discuss whether vitamins can be used as safe health products or dietary supplements. We performed a MEDLINE/PubMed, EMBASE, Scopus and Google Scholar search and assessed reference lists of the included studies which were published from 1993 through 2015. The studies, with an emphasis on RCTs (randomized controlled clinical trials), were reviewed. As some vitamins such as fat-soluble vitamins (vitamin A, vitamin D, vitamin E), and also some of the water-soluble vitamins like folic acid may cause adverse events and some like vitamin C is widely taken assuming that it has so many benefits and no harm, we included relevant studies with negative or undesired results regarding the effect of these vitamins on health. Our recommendation is that taking high-dose supplements of vitamins A, E, D, C, and folic acid is not always effective for prevention of disease, and it can even be harmful to the health.

Evaluation of the prescriptions written for upper respiratory tract infections

OBJECTIVE:

We aimed to determine frequency of antibiotic use and retrospectively evaluate prescriptions written for the patients with diagnosis of acute pharyngitis, acute nasopharyngitis and acute tonsillitis by our hospital emergency department physicians in January 2014.

METHODS:

Records of the patients who were admitted to the education and research hospital between January 1^st, 2014 to January 31^st 2014 were analyzed in this study. Records of all the patients with the diagnosis of acute nasopharyngitis (J.00), acute pharyngitis (J.02) and acute tonsillitis (J.03) were analyzed, and patients with a second diagnosis or haven’t any prescription were excluded from the study. Frequency of antibiotic and other symptomatic medications use were analyzed in prescriptions of 5261 patients.

RESULTS:

Antibiotics were prescribed for 63.5% of the patients included in the study, and the most preferred antibiotics were penicilin and beta-lactamase combination (38.8%) and cephalosporins (26.2%). Combined preparations were the most preferred medications in symptomatic treatment (65.9%). Dexketoprofen was the most preferred among nonsteroidal anti-inflammatory drugs (63%). In each prescription, average number of 3.26 drugs were prescribed.

CONCLUSION:

Excessive and improrer use of antibiotics in the treatment of respiratuary tract infection is a global problem. The use of excess agents in symptomatic medication leads to polypharmacy. Training of physicians and patients on principles of rational drug use will contribute to the solution of this problem.

Intravenous infusion of ascorbic acid decreases serum histamine concentrations in patients with allergic and non-allergic diseases

Histamine plays an important role in the development of symptoms in allergic, infectious, neoplastic and other diseases. Empirical findings have suggested beneficial effects of ascorbic acid supplementation in those diseases, and these effects are assumed to be related to a possible decrease in systemic histamine concentration. In the present study, we systematically investigated for the first time the effect of 7.5 g of intravenously administered ascorbic acid on serum histamine levels (as detected by ELISA) in 89 patients (19 with allergic and 70 with infectious diseases). When all patients were grouped together, there was a significant decline in histamine concentration from 0.83 to 0.57 ng/ml×m2 body surface area (BSA, p<0.0001). The decrease in serum histamine concentration in patients with allergic diseases (1.36 to 0.69 ng/ml×m2 BSA, p=0.0007) was greater than that in patients with infectious diseases (0.73 to 0.56 ng/ml×m2 BSA, p=0.01). Furthermore, the decline in histamine concentration after ascorbic acid administration was positively correlated with the basal, i.e. pre-therapeutic, histamine concentration. Intravenous infusion of ascorbic acid clearly reduced histamine concentrations in serum, and may represent a therapeutic option in patients presenting with symptoms and diseases associated with pathologically increased histamine concentration.

Vitamin C for preventing and treating the common cold

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.

George K, Walsh TJ. Human rhinoviruses

Human rhinoviruses (HRVs), first discovered in the 1950s, are responsible for more than one-half of cold-like illnesses and cost billions of dollars annually in medical visits and missed days of work. Advances in molecular methods have enhanced our understanding of the genomic structure of HRV and have led to the characterization of three genetically distinct HRV groups, designated groups A, B, and C, within the genus Enterovirus and the family Picornaviridae. HRVs are traditionally associated with upper respiratory tract infection, otitis media, and sinusitis. In recent years, the increasing implementation of PCR assays for respiratory virus detection in clinical laboratories has facilitated the recognition of HRV as a lower respiratory tract pathogen, particularly in patients with asthma, infants, elderly patients, and immunocompromised hosts. Cultured isolates of HRV remain important for studies of viral characteristics and disease pathogenesis. Indeed, whether the clinical manifestations of HRV are related directly to viral pathogenicity or secondary to the host immune response is the subject of ongoing research. There are currently no approved antiviral therapies for HRVs, and treatment remains primarily supportive. This review provides a comprehensive, up-to-date assessment of the basic virology, pathogenesis, clinical epidemiology, and laboratory features of and treatment and prevention strategies for HRVs.

Guidelines for the management of adult lower respiratory tract infections--summary

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.

Guidelines for the management of adult lower respiratory tract infections--full version

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. Background sections and graded evidence tables are also included. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.

Echinacea purpurea along with zinc, selenium and vitamin C to alleviate exacerbations of chronic obstructive pulmonary disease: results from a randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

Upper respiratory tract infections (URTI) frequently cause exacerbations of chronic-obstructive pulmonary disease (COPD). Stimulation of the innate immune system may provide an early defence against such infections. The objective of this study was to determine whether Echinacea purpurea (EP) along with micronutrients may alleviate COPD exacerbations caused by acute URTI.

METHODS

This was a double-blind, randomized, placebo-controlled trial in COPD patients with acute URTI. Patients were given ciprofloxacin for 7 days and additionally one tablet per day of EP, of EP along with zinc, selenium and ascorbic acid (EP+), or of placebo until day 14. Serum levels of TNF α and interleukins 1β, 6 and 10 were measured before and after treatment. Until week 4 post-end of treatment, all patients had to daily report on COPD symptoms in diaries.

RESULTS AND DISCUSSION

In total, 108 mostly male patients with a mean age of 65·8 years (40-81 years) were enrolled. Patients of the three treatment arms did not vary significantly in baseline characteristics. EP+, but not EP resulted in significantly less severe and shorter exacerbation episodes following URTI as compared with placebo suggesting a synergistic effect of Echinacea and micronutrients. Large variations in biomarkers in-between and within groups were unrelated to treatment. Study medication was safe and well tolerated with overall 15 adverse events one of which was serious. Among those, sleeping disorders were most frequent and likely related to the underlying disease.

WHAT IS NEW AND CONCLUSION

The combination of EP, zinc, selenium and vitamin C may alleviate exacerbation symptoms caused by URTI in COPD. Further studies are warranted to investigate the interactions among Echinacea, zinc, selenium and vitamin C.

High-dose vitamin C: does it exacerbate the effect of psychosocial stress on liver? Biochemical and histological study

AIM

Chronic stress has been implicated as a contributing factor in liver injury. However, other factors that can contribute to the severity of stress effect in liver injury have not been well characterized. In this study, the combined effect of chronic psychosocial stress and variable dosing levels of vitamin C on liver injury, have been studied.

METHODS

Stress was chronically induced using intruder method. Vitamin C was administered by oral gavage. Both biochemical and histopathological measures were undertaken.

RESULTS

The results showed that low (50mg/kg/day) and moderate (150 mg/kg/day) doses of vitamin C alone or in combination with chronic stress had no effect on liver. However, combination of high dose of vitamin C (500 mg/kg/day) and chronic stress induced various histopathological liver lesions in most of animals in the group that was stressed and supplemented with high dose vitamin C.

CONCLUSION

Results of this study show a dose-dependent effect for vitamin C in exacerbating stress contribution to liver injury.

Comparative effectiveness of medical interventions in adults versus children

OBJECTIVE

To estimate the comparative effectiveness of medical interventions in adults versus children.

STUDY DESIGN

We identified from the Cochrane Database of Systematic Reviews (Issue 1, 2007) meta-analyses with data on at least 1 adult and 1 pediatric randomized trial with binary primary efficacy outcome. For each meta-analysis, we calculated the summary odds ratio of the adult trials and the pediatric trials, respectively; the relative odds ratio (ROR) of the adult versus pediatric odds ratios per meta-analysis; and the summary ROR across all meta-analyses. ROR <1 means that the experimental intervention is more unfavorable in children than adults.

RESULTS

Across 128 eligible meta-analyses (1051 adult and 343 pediatric trials), the summary ROR did not show a statistically significant difference between adults and children (0.96; 95% confidence intervals, 0.86 to 1.08). However, in all meta-analyses except for 1, the individual ROR's 95% confidence intervals could not exclude a relative difference in efficacy over 20%. In two-thirds, the relative difference in observed point estimates exceeded 50%. Nine statistically significant discrepancies were identified; 4 of them were also clinically important.

CONCLUSIONS

Treatment effects are on average similar in adults and children, but available evidence leaves large uncertainty about their relative efficacy. Clinically important discrepancies may occur.

Regular vitamin C supplementation during pregnancy reduces hospitalization: outcomes of a Ugandan rural cohort study

Background

Vitamin C or ascorbic acid is a hydro-soluble lactone (synthesized from glucose) essential to human body and available from diet. Despite its broad availability in fruits and vegetables, in many developing countries the incidence of clinical symptoms due to the vitamin deficiency is still very high. Also, pregnant women in the developing countries are frequently hospitalized for several preventable reasons such as anemia in pregnancy, mostly iron-deficient anemia (IDA) and the upper/lower respiratory tract infections (RTI). The aim of the study was to investigate, in a Ugandan rural pregnant women cohort, the preventive effects of vitamin C supplementation on hospital admission.

Methods

384 pregnant women met the inclusion criteria and were randomly assigned to receive either 400 mg of vitamin C daily (187) or not (197) in addition to their standard antenatal vitamins until delivery. The primary outcome measure of this study was to assess the prevention of hospitalization during pregnancy in the group of women supplemented with vitamin C compared to the controls. Fisher‘s exact test was employed in this assessment.

Results

42.2% women in the vitamin C group and 27.9% in the control group were not hospitalized during pregnancy; this difference was found statistically significant.

Conclusion

The results of this study suggest including vitamin C in the guidelines of multivitamin prevention for pregnant women, especially in developing countries where seasonal availability of fruits and vegetables could result in adverse clinical outcomes.

Combined inhalational and oral supplementation of ascorbic acid may prevent influenza pandemic emergency: a hypothesis

Occurrence of influenza pandemics is a worldwide phenomenon and a significant cause of mortality and morbidity throughout the globe. It is due to mutations in the influenza virus genetic material creating antigenic drift of pathogenic viral proteins resulting in emergence of new influenza virus strains. Therefore, the vaccines available for prevention of influenza offer no protection against influenza pandemics caused by new virus strains. Moreover, the existing drugs used to combat influenza may be ineffective to treat influenza pandemics due to the emergence of drug resistance in the pandemic virus strain. Therefore, a working strategy must be developed to combat influenza pandemics. In this review we have addressed this problem and reviewed the published studies on ascorbic acid in the common cold and influenza and laboratory studies on the effect of ascorbic acid on influenza virus. We have also correlated the clinical and laboratory studies and developed a hypothesis to prevent influenza pandemics.

Examining the evidence for the use of vitamin C in the prophylaxis and treatment of the common cold

Purpose: To present a critical evaluation of the current evidence concerning the therapeutic value of vitamin C for the prophylaxis and treatment of the common cold.

Data sources: Cochrane, PubMed, Natural Standard, and the National Center for Complementary and Alternative Medicine databases were searched to identify and acquire primary research reports, literature reviews, and secondary analyses related to the clinical objective. Published clinical trials, literature reviews, meta‐analyses, and systematic reviews were evaluated for evidence‐based practice implications.

Conclusions: Vitamin C is frequently used for the treatment and prophylaxis of the common cold; however, no published recommendations were found in a review of the nurse practitioner literature that specifically address the efficacy of vitamin C for the common cold. Our literature review revealed that vitamin C is not effective at preventing the common cold in the general adult population; however, it is effective at preventing colds when consumed regularly by athletes training in subarctic conditions. We also found that regular vitamin C consumption may reduce the duration of cold symptoms in both adults and children, but it does not decrease the severity of cold symptoms.

Implications for practice: NPs should counsel their patients that regular vitamin C consumption may decrease the duration of cold symptoms, but does not affect symptom severity or act as a prophylaxis.

Clinical cough V: complementary and alternative medicine: therapy of cough

We review the actions of complementary and alternative medicines (CAMs) in the treatment of cough and of the conditions associated with it; in particular asthma and upper respiratory tract infections. These therapies may work (1) peripherally, at the sites in the airways and lungs at which cough is being activated, (2) in the brainstem, where the neural "cough center" is situated, or (3) at the cerebral cortex, where cough can be initiated, suppressed or modified by conscious or unconscious controls. Of the large number of trials of CAMs against cough, most are inadequate in design. It may be difficult to randomize selection. Blinding is often impossible both for the patient and the therapist, and adequate placebo controls may be difficult to devise. The patient can usually identify the "active" treatment by the taste or smell of a medicine, or from the approach and apparatus being used. Pure chemicals can be extracted from many of the herbs used as antitussives, and can be shown to be effective in randomized, blind, and controlled trials, but it does not follow that the herb itself, used in the recommended formula and shown to be antitussive, acts by this agency unless a placebo effect is ruled out. A few herbs are identified where the evidence points to a true antitussive action. Of nonherbal treatments, the few positive results are usually outweighed by the larger number of negative ones. Thus, in general, CAMs for cough are welcomed enthusiastically by the patient but lack sound evidence for their efficacy. Antitussive chemicals can be extracted from many herbs, but it is no more than a reasonable hypothesis that the herb itself acts through this pathway.

Evaluating the quality of randomized controlled trials that examine the efficacy of natural health products: a systematic review of critical appraisal instruments

The purpose of this project was to conduct a systematic review to identify instruments designed to evaluate the quality of randomized controlled trials (RCTs) of natural health products (NHPs). Instruments were examined for inclusion of items assessing methods, identity and content of the NHP, generalizability of results and instructions for use. Online databases, websites, textbooks and reference lists were searched to identify instruments. Relevance assessment and data extraction of articles were completed by two investigators and disagreements were settled by the third investigator. Data were analyzed using descriptive statistics. Of the 4442 citations identified, 29 were potentially relevant with 16 meeting the criteria for inclusion. None of the instruments stated they were validated; content in the four areas of interest varied considerably. The most common items included randomization sequence generation (100%), blinding (100%), allocation concealment (75%) and participant flow (75%). Only nine of the NHP instruments included at least one item to appraise the specific content of the NHP. The CONSORT Statement for Herbal Interventions most closely addressed the four areas of interest; however, this instrument was specific for herbs. There is a need for the development of a validated instrument for assessment of the quality of RCTs that would be useful for herbs as well as other NHPs.

Respiratory Infections, Acute

Acute respiratory tract infections are an extremely common and important source of morbidity and mortality. Despite advances in our understanding of microbial pathogens and the development of novel antimicrobial agents, acute respiratory tract infections continue to place an enormous burden on global health expenditure. Acute respiratory tract infections can be divided into infections that predominantly affect the upper respiratory tract above the vocal cords and those that affect the lower respiratory tract. The clinical features, causative pathogens, and therapies of common acute respiratory tract infections are detailed in this article.

Vitamin C for preventing and treating the common cold

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.

Update: effects of antioxidant and non-antioxidant vitamin supplementation on immune function

The purpose of this manuscript is to review the impact of supplementation with vitamins E and C, carotenoids, and the B vitamins on parameters of innate and adaptive immune function as reported from clinical trials in humans. There is evidence to support causal effects of supplementation with vitamins E and C and the carotenoids singly and in combination on selected aspects of immunity, including the functional capacity of innate immune cells, lymphocyte proliferation, and the delayed-type hypersensitivity (DTH) response. Controlled intervention trials of B vitamin-containing multivitamin supplements suggest beneficial effects on immune parameters and clinical outcomes in HIV-positive individuals.

Upper respiratory tract infections in athletes

Upper respiratory tract infections (URTIs) represent the most common acute illnesses in the general population and account for the leading acute diagnoses in the outpatient setting. Given the athlete's expectation to return to activity as soon as possible, the sports medicine physician should be able to accurately diagnose and aggressively treat these illnesses. This article discusses the common pathogens, diagnosis, treatment options, and return-to-play decisions for URTIs, with a focus on the common cold, sinusitis, pharyngitis, and infectious mononucleosis in the athlete.

Acute rhinosinusitis in adults: an update on current management

Acute rhinosinusitis is a common disease with worldwide prevalence. It is a significant burden on the health services. It is most commonly caused by viruses and is self-limiting in nature. The diagnosis of acute rhinosinusitis is clinical and sinus radiography is not indicated routinely. Most cases of acute rhinosinusitis are treated symptomatically. However, symptoms may persist beyond 10 days when secondary bacterial infection prevails. Antibiotics are reserved for moderate or severe cases or when there is development of complications of acute rhinosinusitis. This paper provides an update on the current management of acute rhinosinusitis.

Sufficiently important difference for common cold: severity reduction

PURPOSE

We undertook a study to estimate the sufficiently important difference (SID) for the common cold. The SID is the smallest benefit that an intervention would require to justify costs and risks.

METHODS

Benefit-harm tradeoff interviews (in-person and telephone) assessed SID in terms of overall severity reduction using evidence-based simple-language scenarios for 4 common cold treatments: vitamin C, the herbal medicine echinacea, zinc lozenges, and the unlicensed antiviral pleconaril.

RESULTS

Response patterns to the 4 scenarios in the telephone and in-person samples were not statistically distinguishable and were merged for most analyses. The scenario based on vitamin C led to a mean SID of 25% (95% confidence interval [CI] 0.23-0.27). For the echinacea-based scenario, mean SID was 32% (95% CI, 0.30-0.34). For the zinc-based scenario, mean SID was 47% (95% CI, 0.43-0.51). The scenario based on preliminary antiviral trials provided a mean SID of 57% (95% CI, 0.53-0.61). Multivariate analyses suggested that (1) between-scenario differences were substantive and reproducible in the 2 samples, (2) presence or severity of illness did not predict SID, and (3) SID was not influenced by age, sex, tobacco use, ethnicity, income, or education. Despite consistencies supporting the model and methods, response patterns were diverse, with wide spreads of individual SID values within and among treatment scenarios.

CONCLUSIONS

Depending on treatment specifics, people want an on-average 25% to 57% reduction in overall illness severity to justify costs and risks of popular cold treatments. Randomized trial evidence does not support benefits this large. This model and these methods should be further developed for use in other disease entities.

Warned, but not well armed: preventing viral upper respiratory infections in households

ABSTRACT The purpose of this state‐of‐the‐science review was to identify strategies and household‐level interventions for public health nurses to help prevent the acquisition and spread of viral upper respiratory infections (URI) in the community. Even though viral URI are a major global economic and social problem, surprisingly little research has been conducted to attempt to prevent them or reduce their transmission, probably because URI (with the exception of epidemic influenza) are generally considered to be mild and self‐limited. Based on the research to date, public health nurses can use several promising strategies for prevention: (a) provide more tailored educational messages regarding preventive strategies such as vaccination, hand hygiene, spatial separation of infected household members, avoidance of antibiotics to treat viral URI, and environmental cleaning (e.g., for toys or other shared items), which are delivered personally rather than passively (e.g., pamphlets placed in a waiting room); (b) use each patient encounter in any setting to encourage influenza vaccination for relevant risk groups; (c) encourage use of alcohol hand sanitizers by household members during the cold and flu season; and (d) provide opportunities for skill development for adult and child household members (e.g., cover your cough, when to seek care or an antibiotic).

Nutritional therapy and infectious diseases: a two-edged sword

The benefits and risks of nutritional therapies in the prevention and management of infectious diseases in the developed world are reviewed. There is strong evidence that early enteral feeding of patients prevents infections in a variety of traumatic and surgical illnesses. There is, however, little support for similar early feeding in medical illnesses. Parenteral nutrition increases the risk of infection when compared to enteral feeding or delayed nutrition. The use of gastric feedings appears to be as safe and effective as small bowel feedings. Dietary supplementation with glutamine appears to lower the risk of post-surgical infections and the ingestion of cranberry products has value in preventing urinary tract infections in women.

Lower respiratory infections and potential complications in athletes

A review and synthesis of recently published literature regarding lower respiratory infections in athletes was conducted. Diagnosis and treatment of common etiologies, specifically acute bronchitis, pneumonia, and influenza, are examined and discussed. In addition, potential complications, including spontaneous pneumothorax, bronchiectasis, hemoptysis, and acute respiratory failure that may result from inadequate diagnosis and treatment, are addressed. Criteria for allowing athletes to return to play were reviewed and current accepted guidelines for return to activity are discussed.

Vitamin C for preventing and treating the common cold

Whether vitamin C has an effect on the common cold has been a subject of controversy for at least 60 years. What does the evidence show?