Traditional Chinese Medicine for the Common Cold: Evidence and Potential Mechanisms.

Traditional Chinese medicine (TCM) has a history of over 2000 years in treating infectious diseases, among which the clinical treatment of the common cold (colds) and influenza (flu) is the most widespread and well-established. It is difficult to tell the difference between a cold and the flu based on the symptoms alone. The flu vaccine protects against influenza, but there is no vaccine or specific medication to protect against the common cold. Due to the lack of a reliable scientific basis, TCM has not received sufficient attention in Western medicine. Therefore, we systematically evaluated the scientific evidence proving the efficacy of TCM intervention in treating colds for the first time by examining theoretical principles, clinical research, and pharmacological perspectives, as well as the mechanisms behind this efficacy. In TCM theory, there are four important external environmental factors that may cause a cold, which are called "cold, heat, dryness, and dampness". The scientific basis for this theory has been described and will help researchers to understand and recognize its importance. The results of the systematic review of high-quality randomized controlled clinical trials (RCTs) have shown that TCM is effective and safe for the treatment of colds. Therefore, TCM might be used as a complementary or alternative approach to cold treatment and management. Some clinical trials have demonstrated that TCM may have potential therapeutic effects in preventing colds and treating their sequelae. However, more high-quality, large-scale randomized controlled trials should be conducted in the future for further verification. Pharmacological studies have shown that active ingredients extracted from TCM for treating colds have antiviral, anti-inflammatory, immune-regulating, and anti-oxidative properties. We expect that this review will guide the optimization and rationalization of TCM clinical practice and scientific research in the treatment of colds.

Vitamin C supplementation reduces the odds of developing a common cold in Republic of Korea Army recruits: randomised controlled trial.

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.

Effects and safety of herbal medicines among community-dwelling residents during COVID-19 pandemic: A large prospective, randomized controlled trial (RCT).

BACKGROUND: Since the declaration of COVID-19 as a global pandemic by the World Health Organization, countries are struggling with a shortage of medical capacities. It would be essential if the risk for preventable comorbidities, such as the common cold, can be reduced or prevented, so that the scarce medical resources and facilities can be focused on COVID-19. PURPOSE: To evaluate the effects of two herbal medicines (Jinhaoartemisia antipyretic granules and Huoxiangzhengqi oral liquids) in reducing the risk of the common cold in community-dwelling residents in China during the COVID-19 outbreak. STUDY DESIGN: A prospective open-label, parallel-group, cluster-randomized controlled trial (RCT), was conducted in Chengdu, China. METHODS: A total of 22,065 participants from 11 communities were recruited during a period of one month. The trial started on 30 January and participants were followed up till 29 February 2020. Participants were randomly assigned to receive either a five-day herbal medicine therapy plus a reference manual or a reference manual only if they were allocated to the control group. The primary endpoint was the occurrence of patient-reported common cold symptoms. The secondary endpoint was the time in days from the receipt of herbal drugs/reference manual and the occurrence of the common cold symptoms. RESULTS: Use of herbal medicine reduced the risk of the common cold by 89.6% (95% CI, 52.9% to 97.7%) in all community-dwelling residents, and by 94.0% (95% CI, 52.1% to 99.2%) in residents aged between 16 and 59 years old. Sensitivity analyses showed similar results. CONCLUSION: This community-based RCT found that the use of a herbal medicine therapy (Jinhaoartemisia antipyretic granules and Huoxiangzhengqi oral liquids) could significantly reduce the risks of the common cold among community-dwelling residents, suggesting that herbal medicine may be a useful approach for public health intervention to minimize preventable morbidity during COVID-19 outbreak.

The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19.

From Pauling's theories to the present, considerable understanding has been acquired of both the physiological role of vitamin C and of the impact of vitamin C supplementation on the health. Although it is well known that a balanced diet which satisfies the daily intake of vitamin C positively affects the immune system and reduces susceptibility to infections, available data do not support the theory that oral vitamin C supplements boost immunity. No current clinical recommendations support the possibility of significantly decreasing the risk of respiratory infections by using high-dose supplements of vitamin C in a well-nourished general population. Only in restricted subgroups (e.g., athletes or the military) and in subjects with a low plasma vitamin C concentration a supplementation may be justified. Furthermore, in categories at high risk of infection (i.e., the obese, diabetics, the elderly, etc.), a vitamin C supplementation can modulate inflammation, with potential positive effects on immune response to infections. The impact of an extra oral intake of vitamin C on the duration of a cold and the prevention or treatment of pneumonia is still questioned, while, based on critical illness studies, vitamin C infusion has recently been hypothesized as a treatment for COVID-19 hospitalized patients. In this review, we focused on the effects of vitamin C on immune function, summarizing the most relevant studies from the prevention and treatment of common respiratory diseases to the use of vitamin C in critical illness conditions, with the aim of clarifying its potential application during an acute SARS-CoV2 infection.

Zinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation.

The common cold had resulted in significant economic and social burden worldwide. The effect of vitamin C on preventing common cold in healthy adults has been investigated extensively, but not that of other micronutrients. Thus, we aim to assess the effects of providing micronutrients singly through oral means, on cold incidence, and/or management (in terms of cold duration and symptom severity) in healthy adults from systematically searched randomized controlled trials. From four electronic databases, 660 identified studies were screened and data were extracted from 20 studies (zinc, 10; vitamin D, 8; and vitamins A and E, 2). The quality of selected studies was assessed using the Cochrane risk of bias tool and certainty in the outcomes was assessed with the Grading of Recommendations Assessment, Development and Evaluation approach. The review found that micronutrients supplementation, except vitamin C, may not prevent cold incidence or reduce symptom severity among healthy adults. However, zinc supplementation was observed to potentially reduce cold duration by 2.25 days (when zinc is provided singly, 95% CI: -3.39, -1.12). This suggests that zinc supplementation may reduce the overall burden due to common cold among healthy adults.

Beetroot juice supplementation for the prevention of cold symptoms associated with stress: A proof-of-concept study.

OBJECTIVES: Psychological stress has been linked to common cold symptoms. Nitric oxide (NO) is part of the first line of epithelial defense against pathogens, and beetroot juice is a source of dietary nitrate that increases NO availability. We therefore tested whether beetroot juice protects against cold symptoms in a period of sustained acute stress. DESIGN: Seventy-six students, 16 of these with asthma, were randomly assigned to seven daily doses of beetroot juice or no supplementation control during their final exams. METHODS: Participants completed stress ratings, a cold symptom questionnaire, and exhaled NO measurements at a low-stress period and two periods during their final exams, with one questionnaire follow-up assessment seven days after finals. RESULTS: Beetroot juice was associated with reduced symptoms of cold and sickness during and following finals. Those with asthma showed the greatest benefits. Higher exhaled NO was concurrently and prospectively associated with reduced symptomatology. CONCLUSION: Beetroot juice during periods of psychological stress protects against cold symptoms. Preliminary evidence suggests particular benefits in asthma, which could translate into reduced asthma exacerbations due to respiratory infections. Clinical Trial ID: NCT03159273.

Understanding attitudes toward hygiene mask use in Japanese daily life by using a repeated cross-sectional survey.

BACKGROUND: During the 2009 H1N1 influenza epidemic, roughly half of survey respondents reported having worn a hygiene mask. However, most were unsatisfied with commercially available masks. OBJECTIVE: The long-term goal was to develop a comfortable, high-performance hygiene mask. This study investigated holistic attitudes of mask wearers and identified the most prominent problems as a basis for developing a new mask. METHODS: In 2009, 2012, and 2015, identical surveys were conducted among Japanese university students. The rate of mask use, intended uses, and problems reported while wearing a mask were aggregated. Co-occurrence analysis of individual respondents' data was conducted. RESULTS: For men, the most intended uses were influenza prevention in 2009 and common cold prevention in 2012 and 2015; common problems were humidity in the mask, glasses misting over, and breathing difficulty. For women, the most intended use was common cold prevention in all 3 years; common problems were humidity, glasses misting over, breathing difficulty, and makeup coming off. CONCLUSIONS: Men's attitudes in 2009 were different from those in 2012 and 2015. However, women's major attitudes were consistent in all 3 years. For both sexes, the most commonly reported problem was humidity in all 3 years. It is expected that more comfortable masks for daily use will result from improving humidity characteristics.

Effect of Tea Catechins on Influenza Infection and the Common Cold with a Focus on Epidemiological/Clinical Studies.

Influenza and the common cold are acute infectious diseases of the respiratory tract. Influenza is a severe disease that is highly infectious and can progress to life-threating diseases such as pneumonia or encephalitis when aggravated. Due to the fact that influenza infections and common colds spread easily via droplets and contact, public prevention measures, such as hand washing and facial masks, are recommended for influenza prophylaxis. Experimental studies have reported that tea catechins inhibited influenza viral adsorption and suppressed replication and neuraminidase activity. They were also effective against some cold viruses. In addition, tea catechins enhance immunity against viral infection. Although the antiviral activity of tea catechins has been demonstrated, the clinical evidence to support their utility remains inconclusive. Since the late 1990s, several epidemiological studies have suggested that the regular consumption of green tea decreases influenza infection rates and some cold symptoms, and that gargling with tea catechin may protect against the development of influenza infection. This review briefly summarizes the effect of tea catechins on influenza infection and the common cold with a focus on epidemiological/clinical studies, and clarifies the need for further studies to confirm their clinical efficacy.

Effect of High-Dose vs Standard-Dose Wintertime Vitamin D Supplementation on Viral Upper Respiratory Tract Infections in Young Healthy Children.

IMPORTANCE: Epidemiological studies support a link between low 25-hydroxyvitamin D levels and a higher risk of viral upper respiratory tract infections. However, whether winter supplementation of vitamin D reduces the risk among children is unknown. OBJECTIVE: To determine whether high-dose vs standard-dose vitamin D supplementation reduces the incidence of wintertime upper respiratory tract infections in young children. DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial was conducted during the winter months between September 13, 2011, and June 30, 2015, among children aged 1 through 5 years enrolled in TARGet Kids!, a multisite primary care practice-based research network in Toronto, Ontario, Canada. INTERVENTIONS: Three hundred forty-nine participants were randomized to receive 2000 IU/d of vitamin D oral supplementation (high-dose group) vs 354 participants who were randomized to receive 400 IU/d (standard-dose group) for a minimum of 4 months between September and May. MAIN OUTCOME MEASURES: The primary outcome was the number of laboratory-confirmed viral upper respiratory tract infections based on parent-collected nasal swabs over the winter months. Secondary outcomes included the number of influenza infections, noninfluenza infections, parent-reported upper respiratory tract illnesses, time to first upper respiratory tract infection, and serum 25-hydroxyvitamin D levels at study termination. RESULTS: Among 703 participants who were randomized (mean age, 2.7 years, 57.7% boys), 699 (99.4%) completed the trial. The mean number of laboratory-confirmed upper respiratory tract infections per child was 1.05 (95% CI, 0.91-1.19) for the high-dose group and 1.03 (95% CI, 0.90-1.16) for the standard-dose group, for a between-group difference of 0.02 (95% CI, -0.17 to 0.21) per child. There was no statistically significant difference in number of laboratory-confirmed infections between groups (incidence rate ratio [RR], 0.97; 95% CI, 0.80-1.16). There was also no significant difference in the median time to the first laboratory-confirmed infection: 3.95 months (95% CI, 3.02-5.95 months) for the high-dose group vs 3.29 months (95% CI, 2.66-4.14 months) for the standard-dose group, or number of parent-reported upper respiratory tract illnesses between groups (625 for high-dose vs 600 for standard-dose groups, incidence RR, 1.01; 95% CI, 0.88-1.16). At study termination, serum 25-hydroxyvitamin D levels were 48.7 ng/mL (95% CI, 46.9-50.5 ng/mL) in the high-dose group and 36.8 ng/mL (95% CI, 35.4-38.2 ng/mL) in the standard-dose group. CONCLUSIONS AND RELEVANCE: Among healthy children aged 1 to 5 years, daily administration of 2000 IU compared with 400 IU of vitamin D supplementation did not reduce overall wintertime upper respiratory tract infections. These findings do not support the routine use of high-dose vitamin D supplementation in children for the prevention of viral upper respiratory tract infections. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01419262.

Prevention and Treatment of Influenza, Influenza-Like Illness, and Common Cold by Herbal, Complementary, and Natural Therapies.

In recent years viral respiratory tract infections, especially influenza viruses, have had a major impact on communities worldwide as a result of unavailability of effective treatment or vaccine. The frequent alterations in the antigenic structures of respiratory viruses, particularly for RNA viruses, pose difficulties in production of effective vaccines. The unavailability of optimal medication and shortage of effective vaccines suggests the requirement for alternative natural therapies. Several herbal remedies were used for prevention and treatment viral respiratory illnesses. Among those that were found effective included maoto, licorice roots, antiwei, North American ginseng, berries, Echinacea, plants extracted carnosic acid, pomegranate, guava tea, and Bai Shao. There is scientific evidence regarding the effectiveness of several complementary therapies for colds. Oral zinc may reduce the length and severity of a cold. Taking vitamin C supplements on a regular basis only slightly reduces the length and severity of colds. Probiotics were found better than placebo in reducing the number episodes of acute upper respiratory tract infections, the rate of episodes of acute upper respiratory tract infection and reducing antibiotic use. Alkaline diets or drinks might have antiviral properties as in vitro studies demonstrated inactivation effect of alkaline medium on respiratory virus. Earthing might have a natural anti-inflammatory effect for human body. It is now accepted that an overwhelming inflammatory response is the cause of human deaths from avian H5N1 influenza infection. Earthing accelerates immune response following vaccination, as demonstrated by increases of gamma globulin concentration. No in vivo or clinical studies were found that investigate the role of alkalization or earthing on respiratory viral infections. Thus, future studies are recommended to reveal any potential curative effects.

Echinacea purpurea: A Proprietary Extract of Echinacea purpurea Is Shown to be Safe and Effective in the Prevention of the Common Cold.

The research study in this review represents the largest clinical trial to date that evaluated the safety and efficacy of Echinacea purpurea for prophylactic treatment of the common cold, in addition to investigating its risk-benefit in a long-term treatment period. The clinical application of the proprietary standardized Echinacea purpurea extract(Echinaforce) demonstrated efficacy as a preventive cold treatment option over a 4-month duration. This study showed that Echinacea's long-term prevention was associated with a reduction in the total number of cold episodes, a reduction in the number of days with colds, and a reduction in cold episodes requiring additional medication. Furthermore, the Echinacea test agent inhibited virally confirmed colds, exhibited maximal effects on recurrent infections, and demonstrated that its preventive effects increased relative to therapy compliance and adherence to the protocol. In summary, Echinacea purpurea when taken as recommended for the prevention of the common cold appears to provide a positive risk to benefit ratio.

Echinacea for preventing and treating the common cold.

CLINICAL QUESTION: Are Echinacea products associated with a reduced incidence and a shorter duration of common colds compared with placebo? BOTTOM LINE: Individual prophylaxis trials show no association with prevention of the common cold, but exploratory meta-analysis suggests that Echinacea products may be associated with a small reduction in cold incidence. In treatment trials, there was no association of Echinacea products with a shorter duration of colds.

Garlic for the common cold.

Background Garlic is alleged to have antimicrobial and antiviral properties that relieve the common cold, among other beneficial effects. There is widespread usage of garlic supplements. The common cold is associated with significant morbidity and economic consequences. On average, children have six to eight colds per year and adults have two to four.Objectives To determine whether garlic (Allium sativum) is effective for the prevention or treatment of the common cold, when compared to placebo, no treatment or other treatments.Search methods We searched CENTRAL (2014, Issue 7),OLDMEDLINE (1950 to 1965),MEDLINE (January 1966 to July week 5, 2014), EMBASE(1974 to August 2014) and AMED (1985 to August 2014).Selection criteria Randomised controlled trials of common cold prevention and treatment comparing garlic with placebo, no treatment or standard treatment.Data collection and analysis Two review authors independently reviewed and selected trials from searches, assessed and rated study quality and extracted relevant data.Main results In this updated review, we identified eight trials as potentially relevant from our searches. Again, only one trial met the inclusion criteria.This trial randomly assigned 146 participants to either a garlic supplement (with 180 mg of allicin content) or a placebo (once daily)for 12 weeks. The trial reported 24 occurrences of the common cold in the garlic intervention group compared with 65 in the placebo group (P value < 0.001), resulting in fewer days of illness in the garlic group compared with the placebo group (111 versus 366). The number of days to recovery from an occurrence of the common cold was similar in both groups (4.63 versus 5.63). Only one trial met the inclusion criteria, therefore limited conclusions can be drawn. The trial relied on self reported episodes of the common cold but was of reasonable quality in terms of randomisation and allocation concealment. Adverse effects included rash and odour. Authors' conclusions There is insufficient clinical trial evidence regarding the effects of garlic in preventing or treating the common cold. A single trial suggested that garlic may prevent occurrences of the common cold but more studies are needed to validate this finding. Claims of effectiveness appear to rely largely on poor-quality evidence.

Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: a randomized controlled trial.

The early indications of vitamin C deficiency are unremarkable (fatigue, malaise, depression) and may manifest as a reduced desire to be physically active; moreover, hypovitaminosis C may be associated with increased cold duration and severity. This study examined the impact of vitamin C on physical activity and respiratory tract infections during the peak of the cold season. Healthy non-smoking adult men (18-35 years; BMI < 34 kg/m2; plasma vitamin C < 45 µmol/L) received either 1000 mg of vitamin C daily (n = 15) or placebo (n = 13) in a randomized, double-blind, eight-week trial. All participants completed the Wisconsin Upper Respiratory Symptom Survey-21 daily and the Godin Leisure-Time Exercise Questionnaire weekly. In the final two weeks of the trial, the physical activity score rose modestly for the vitamin C group vs. placebo after adjusting for baseline values: +39.6% (95% CI [-4.5,83.7]; p = 0.10). The number of participants reporting cold episodes was 7 and 11 for the vitamin C and placebo groups respectively during the eight-week trial (RR = 0.55; 95% CI [0.33,0.94]; p = 0.04) and cold duration was reduced 59% in the vitamin C versus placebo groups (-3.2 days; 95% CI [-7.0,0.6]; p = 0.06). These data suggest measurable health advantages associated with vitamin C supplementation in a population with adequate-to-low vitamin C status.

Echinacea for preventing and treating the common cold.

BACKGROUND: Echinacea plant preparations (family Asteraceae) are widely used in Europe and North America for common colds. Most consumers and physicians are not aware that products available under the term Echinacea differ appreciably in their composition, mainly due to the use of variable plant material, extraction methods and the addition of other components. OBJECTIVES: To assess whether there is evidence that Echinacea preparations are effective and safe compared to placebo in the prevention and treatment of the common cold. SEARCH METHODS: We searched CENTRAL 2013, Issue 5, MEDLINE (1946 to May week 5, 2013), EMBASE (1991 to June 2013), CINAHL (1981 to June 2013), AMED (1985 to February 2012), LILACS (1981 to June 2013), Web of Science (1955 to June 2013), CAMBASE (no time limits), the Centre for Complementary Medicine Research (1988 to September 2007), WHO ICTRP and clinicaltrials.gov (last searched 5 June 2013), screened references and asked experts in the field about published and unpublished studies. SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing mono-preparations of Echinacea with placebo. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed eligibility and trial quality and extracted data. The primary efficacy outcome was the number of individuals with at least one cold in prevention trials and the duration of colds in treatment trials. For all included trials the primary safety and acceptability outcome was the number of participants dropping out due to adverse events. We assessed trial quality using the Cochrane 'Risk of bias' tool. MAIN RESULTS: Twenty-four double-blind trials with 4631 participants including a total of 33 comparisons of Echinacea preparations and placebo met the inclusion criteria. A variety of different Echinacea preparations based on different species and parts of plant were used. Evidence from seven trials was available for preparations based on the aerial parts of Echinacea purpurea. Ten trials were considered to have a low risk of bias, six to have an unclear risk of bias and eight to have a high risk of bias. Ten trials with 13 comparisons investigated prevention and 15 trials with 20 comparisons investigated treatment of colds (one trial addressed both prevention and treatment).Due to the strong clinical heterogeneity of the studies we refrained from pooling for the main analysis. None of the 12 prevention comparisons reporting the number of patients with at least one cold episode found a statistically significant difference. However a post hoc pooling of their results, suggests a relative risk reduction of 10% to 20%. Of the seven treatment trials reporting data on the duration of colds, only one showed a significant effect of Echinacea over placebo. The number of patients dropping out or reporting adverse effects did not differ significantly between treatment and control groups in prevention and treatment trials. However, in prevention trials there was a trend towards a larger number of patients dropping out due to adverse events in the treatment groups. AUTHORS' CONCLUSIONS: Echinacea products have not here been shown to provide benefits for treating colds, although, it is possible there is a weak benefit from some Echinacea products: the results of individual prophylaxis trials consistently show positive (if non-significant) trends, although potential effects are of questionable clinical relevance.

Perfil de eficacia y seguridad de Echinacea purpurea en la prevención de episodios de resfriado común: estudio clínico aleatorizado, doble ciego y controlado con placebo / Safety and efficacy profile of Echinacea purpurea to prevent common cold episodes: a randomized, double-blind, placebo-controlled trial

Objetivo: Investigar la seguridad y la eficacia de un extracto de Echinacea purpurea en la prevención del resfriado común en una amplia población durante un período de 4 meses. Método: 755 sujetos sanos recibieron un extracto etanólico de E. purpurea(95% parte aérea florida y 5% de raíz) fresca o placebo. A los participantes se les solicitó registrar en un diario los acontecimientos adversos y evaluar los síntomas relacionados con el resfriado, durante todo el período del estudio. Se tomaron muestras de las secreciones nasales de los participantes que padecieron resfriados agudos y fueron examinadas en busca de virus. Resultados: Ocurrieron un total de 293 acontecimientos adversos en el grupo al que se le asignó la equinácea y 306 en el grupo placebo. El 9% de los participantes experimentó acontecimientos adversos, que se consideraron al menos posiblemente, relacionados con el extracto (reacciones adversas), frente al 10% en el grupo placebo. Por lo tanto, la seguridad de la equinácea no fue inferior a la del placebo. La equinácea redujo el número total de episodios de resfriados, los días acumulados de resfriado y los episodios comedicados con analgésicos y antiinflamatorios. Asimismo inhibió los resfriados virales confirmados por deteccion del virus y previno especialmente las infecciones de los virus con membrana (p<0,05) La equinácea demostró mayor eficacia en las infecciones recurrentes y los efectos preventivos aumentaron cuando se cumplió estrictamente con el tratamiento y con el protocolo. Conclusión: La toma profiláctica de E. purpurea durante un período de 4 meses proporcionó una relación beneficio/riesgo positiva (AU)

Objective: To investigate the safety (risk) and efficacy (benefit) of Echinacea purpurea extract in the prevention of common cold episodes in a large population over a 4-month period. Methods: 755 healthy subjects were allocated to receive either an alcohol extract from freshly harvested E. purpurea (95% herba and 5% root) or placebo. Participants were required to record adverse events and to rate cold-related issues in a diary throughout the investigation period. Nasal secretions were sampled at acute colds and screened for viruses. Results: A total of 293 adverse events occurred with Echinacea and 306 with placebo treatment. Nine and 10% of participants experienced adverse events, which were at least possibly related to the study drug (adverse drug reactions).Thus, the safety of Echinacea was noninferior to placebo. Echinacea reduced the total number of cold episodes, cumulated episode days within the group, and pain-killer medicated episodes. Echinacea inhibited virally confirmed colds and especially prevented enveloped virus infections (p < 0.05). Echinacea showed maximal effects on recurrent infections, and preventive effects increased with therapy compliance and adherence to the protocol. Conclusions: Compliant prophylactic intake of E. purpurea over a 4-month period appeared to provide a positive risk to benefit ratio (AU)

Zinc for the common cold.

BACKGROUND: The common cold is one of the most widespread illnesses and is a leading cause of visits to the doctor and absenteeism from school and work. Trials conducted in high-income countries since 1984 investigating the role of zinc for the common cold symptoms have had mixed results. Inadequate treatment masking and reduced bioavailability of zinc from some formulations have been cited as influencing results. OBJECTIVES: To assess whether zinc (irrespective of the zinc salt or formulation used) is efficacious in reducing the incidence, severity and duration of common cold symptoms. In addition, we aimed to identify potential sources of heterogeneity in results obtained and to assess their clinical significance. SEARCH METHODS: In this updated review, we searched CENTRAL (2012, Issue 12), MEDLINE (1966 to January week 2, 2013), EMBASE (1974 to January 2013), CINAHL (1981 to January 2013), Web of Science (1985 to January 2013), LILACS (1982 to January 2013), WHO ICTRP and clinicaltrials.gov. SELECTION CRITERIA: Randomised, double-blind, placebo-controlled trials using zinc for at least five consecutive days to treat, or for at least five months to prevent the common cold. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed trial quality. MAIN RESULTS: Five trials were identified in the updated searches in January 2013 and two of them did not meet our inclusion criteria. We included 16 therapeutic trials (1387 participants) and two preventive trials (394 participants). Intake of zinc was associated with a significant reduction in the duration (days) (mean difference (MD) -1.03, 95% confidence interval (CI) -1.72 to -0.34) (P = 0.003) (I(2) statistic = 89%) but not the severity of common cold symptoms (MD -1.06, 95% CI -2.36 to 0.23) (P = 0.11) (I(2) statistic = 84%). The proportion of participants who were symptomatic after seven days of treatment was significantly smaller (odds ratio (OR) 0.45, 95% CI 0.20 to 1.00) (P = 0.05) than those in the control, (I(2 )statistic = 75%). The incidence rate ratio (IRR) of developing a cold (IRR 0.64, 95% CI 0.47 to 0.88) (P = 0.006) (I(2) statistic = 88%), school absence (P = 0.0003) and prescription of antibiotics (P < 0.00001) was lower in the zinc group. Overall adverse events (OR 1.58, 95% CI 1.19 to 2.09) (P = 0.002), bad taste (OR 2.31, 95% CI 1.71 to 3.11) (P < 0.00001) and nausea (OR 2.15, 95% CI 1.44 to 3.23) (P = 0.002) were higher in the zinc group. The very high heterogeneity means that the averaged estimates must be viewed with caution. AUTHORS' CONCLUSIONS: Zinc administered within 24 hours of onset of symptoms reduces the duration of common cold symptoms in healthy people but some caution is needed due to the heterogeneity of the data. As the zinc lozenges formulation has been widely studied and there is a significant reduction in the duration of cold at a dose of ≥ 75 mg/day, for those considering using zinc it would be best to use it at this dose throughout the cold. Regarding prophylactic zinc supplementation, currently no firm recommendation can be made because of insufficient data. When using zinc lozenges (not as syrup or tablets) the likely benefit has to be balanced against side effects, notably a bad taste and nausea.

Garlic in clinical practice: an evidence-based overview.

BACKGROUND AND OBJECTIVE: Garlic has been widely used in clinical practice, and there were many systematic reviews (SRs) describing its effects. But none reviewed the clinical utility comprehensively, so we aimed to evaluate its effects from every aspect of its effects. METHODS: We comprehensively searched medical electronic databases, asked the experts in this field, along with reference tracking, and manual searching. We included all kinds of SRs, including Cochrane SRs and non-Cochrane SRs. Two authors independently selected articles for relevant SRs, and extracted data of included SRs, resolved differences by consultation with a third reviewer. RESULTS: We described nine SRs about garlic. Available evidence showed that garlic can reduce blood pressure (BP) in hypertensive patients and patients with elevated systolic BP (SBP), but not in normotensive subjects. Evidence about the effects of garlic on lipid parameters was contentious, so we cannot make a decision whether garlic is effective enough for reducing total cholesterol (TC), triglycerides (TAG), and high-density lipoprotein (HDL). As evidence was very limited and insufficient, relations between garlic intake and reduced risks of all kinds of cancers, antiglycemic and antithrombotic effects of garlic, the effects of garlic on cardiovascular morbidity and mortality were unclear. Garlic as a preventative or treatment option for the common cold or peripheral arterial occlusive disease or pre-eclampsia and its complications could not be recommended, as only one relatively small trial evaluated the effects separately. CONCLUSIONS: Garlic might be effective in some areas of clinical practice, but the evidence levels were low, so further researches should be well designed using rigorous method to avoid potential biases.