9 Ways to Defend Yourself Against Viruses (Including Coronavirus)
The common cold is a diverse group of diseases caused by numerous viruses that belong to several different families. Some of them are: picornaviruses (notably, rhinoviruses and enteroviruses), coronaviruses, adenoviruses, parainfluenza viruses, influenza viruses, meta-pneumoviruses and respiratory syncytial viruses.
They all cause the common symptoms of nasal stuffiness and discharge, sneezing, sore throat and cough. Other symptoms may also include hoarseness, headache, malaise and lethargy. The transmission of these viruses occurs via contact with secretions or small- or large-particle aerosols.
On average, children have six to eight and adults two to four colds per year.
Due to the many different virus types, all with varying mechanisms of infection, it is understandable that an effective universal treatment for the common cold has not been developed. Currently available treatments may relieve the symptoms of the common cold. Yet, reviews indicate that the effectiveness of these treatments are limited or uncertain.
Besides drugs, there are a number of natural molecules that have been shown to have a prevent infections and have a therapeutic effect. Below we detail the scientific evidence with regard to these molecules.
Intravenous Vitamin C
Vitamin C, also known as ascorbic acid, is an antioxidant, is anti-inflammatory, and plays an important role in preventing common cold. In addition, a few studies have shown that vitamin C deficiency is related to the increased risk and severity of infections. 
Vitamin C could shorten the duration of the common cold effectively . In some cases (athletes, skiers, art workers, military exercises), it has been shown to effectively prevent the common cold.
One study showed that symptoms of flu and cold in a test group decreased 85% compared with the control group after the administration of megadose Vitamin C. Vitamin C in megadoses (1g/h at the beginning of symptoms for 6h, followed by 3 * 1g/day) administered before or after the appearance of cold and flu symptoms has been shown to relieve and prevent the symptoms in the test population compared with the control group.
According to recent knowledge, people with viral infections have low serum levels of vitamin C, which may be due to increased utilization of vitamin C for the detoxification of reactive oxygen species (ROS) during inflammation caused by infection. Viral infections produce severe oxidative stress, contributing to cellular damage and disease progression. Low serum vitamin C in these individuals may be due to the increase in inflammatory and oxidative processes that take place during a pathological state.
In recent years, vitamin C has been under study for its role as an antiviral agent, either by itself or as an adjunctive therapy to be administered in company with a conventional treatment. It was shown that vitamin C at sufficiently high doses can prevent viral disease and greatly speed recovery from an acute viral infection.
Several mechanisms for vitamin C’s antiviral effect are known or suggested from these studies. First, the antioxidant property of vitamin C promotes a reducing environment in the bloodstream and tissues, enhancing the body’s response to oxidative stress from inflammation, thereby helping to fight microbes and viruses that propagate in stressful conditions.
Vitamin C is also involved in enhancing several functions of the immune system. Cells of the immune system have one of the highest concentrations of vitamin C: white blood cells have an 80 times concentration of vitamin C in their cytoplasm, allowing them to create a vitamin C concentration surplus at the site of infection. Vitamin C can also enhance the production of interferon, which helps prevent cells from being infected by a virus, stimulate the activity of antibodies and cytokines, and in mega-doses, play a role in mitochondrial energy production. It can enhance the ability of specialized immune cells to ingest bacteria.
Data suggests that high dose (7.5 to 50 grams) intravenous vitamin C (IVC) therapy may have a positive effect on disease duration and may reduce viral antibody levels.
The benefit seems to be dependent upon the number of IVC treatments given, as patients given ten or more IVCs had significantly greater reduction in viral antibody load when compared to untreated controls. 
There is a strong advocacy movement for large doses of vitamin C. Some authors argue that the biological half-life for vitamin C at high plasma levels is about 30 minutes. Clinical trials have demonstrated that ascorbate may indeed be effective against tumors when administered intravenously.
Recent studies confirmed that plasma vitamin C concentrations vary substantially with the route of administration. Only by intravenous administration, the necessary ascorbate levels to kill cancer cells are reached in both plasma and urine.
Oxidative stress is considered to be part of the pathogenic mechanism and is closely linked to inflammation. Attenuation of oxidative stress would be expected to reduce oxidative damage. Antioxidants have been found to be effective in alleviating lung injury and protecting against damage to other organs.
Oxidative stress is closely linked to inflammation. Increased production of interleukin (IL)-8 and tumor necrosis factor (TNF)- a, both attract inflammatory cells and increase oxidant production by these cells. Lung cells release inflammatory mediators and cytokines, such as TNF-a, IL-1, and IL-8, in response to oxidative stress.
TNF-a acts on mitochondria to generate reactive oxygen species (ROS), which take part in the activation of NF-kB and AP-1 (redox-sensitive transcription factors). Activation of NF-kB/AP-1 leads to the co-ordinate expression of antioxidant protective and proinflammatory genes. Attenuation of oxidative stress would be expected to result in reduced pulmonary damage.
Antioxidants have been found to be effective in alleviating lung injury and protecting against damage of other organs, such as the heart, kidney, and liver in animal models of oxidative stress.
N-acetylcysteine (NAC), a thiol reducing agent, has mucolytic properties of degrading the disulfide bonds (S–S) to a sulfhydryl bond (–SH) in mucoprotein complexes that no longer crosslinking. And it may also reduce the mucus elasticity and viscosity and facilitate the removal of pulmonary secretions. Moreover, it prevents bacterial stimulation of mucin production and mucus hyper-secretion.
NAC exhibits direct as well as indirect antioxidant properties. Its direct effect is due to a free thiol group interacting with and scavenging ROS. Its indirect antioxidant effect is related to its role as glutathione (GSH) precursor, resulting in increase of intracellular GSH concentration.
The administration of NAC in chronic obstructive pulmonary disease (COPD) and COPD exacerbations has shown benefit. High dose NAC ameliorated oxidative stress and inflammatory response in COPD exacerbation patients. NAC pretreatment also significantly prevented TNF-a production in alveolar macrophages treated with ultrafine nickel particles. High dose NAC therapy showed benefit in H1N1 influenza pneumonia patients. Our present study aimed to compare the effect of NAC addition versus conventional treatment on oxidative stress, inflammatory factors, and radiological changes in CAP patients
N-acetylcysteine, a glutathione precursor, can replenish the total combined thiols (cysteine, cysteinylglycine, glutathione and homocysteine), interact with the electrophile groups of ROS, and then raise the total anti-oxidant capacity.
(Nrf2), which is a redox-sensitive transcription factor and is a key regulator of the antioxidant defense system. NAC pretreatment effectively prevented thiobarbituric reactive substances accumulation, lung edema, and polymorphonuclear neutrophil (PMN) influx into the lungs induced by concentrated ambient thiobarbituric particles. Previous studies have demonstrated the potential antioxidant, anti-inflammatory and mucolytic properties of NAC in COPD. Addition of NAC to the standard treatment of COPD exhibited beneficial effects in disease exacerbations, symptom improvement, and a decline in oxidative stress parameters. High dose NAC improves clinical outcome of COPD exacerbation patients by ameliorating oxidative stress and inflammatory response thereby improving lung spirometry and pulmonary oxygenation. Besides, NAC meets the need by virtue of its anti-inflammatory action. Study indicates that IL-8, IL-6, and TNF-a could be strongly inhibited by NAC at the expression and release level in alveolar type II cells infected with influenza virus A and B and respiratory syncytial virus. NAC inhibited the activation of NF-kB in alveolar macrophages induced by TNF-a, and was an effective inhibitor of TNF-a/IL-1 b-stimulated intercellular adhesion molecule-1 (ICAM-1) and IL-8 release in endothelial and epithelial cells.
NAC administered at high concentrations significantly inhibited the release of IL-1b, IL-8, and TNF-a induced by lipopolysaccharide (LPS) incubation in an ex-vivo model of COPD exacerbation.
But, on the other hand, some long-term effectiveness is reported in several in vivo studies even at low doses. The lower doses of NAC given in vivo might require longer time in order to achieve sustained effects on the cellular thiols which lead to changes in the redox status. This showed that high dose NAC (1200mg/d) significantly decreased IL-8 levels after 10 days of treatment in patients with COPD exacerbations. In one study, administration with NAC (1200mg/d) for 7 days could significantly decreas TNF-a levels in CAP patients. Most studies have shown NAC increased the SOD level or activity in lung injury.
Research showed that NAC increased the protein and mRNA expression of MnSOD without altering the mRNA expression of other antioxidant enzymes, including GPx1 (glutathione peroxydase 1), CuZnSOD, and extracellular SOD (ecSOD). Three isoforms of SOD have been found in mammalian cells: CuZnSOD, MnSOD, and ecSOD. We suppose that the effect of NAC on SOD might be determined by the kind of SOD, detecting time, and some other factors. Different results might be found by alternative methods of administering NAC. Inhalation of NAC solution can directly act on the airway, so that it might come into effect rapidly, with high bioavailability. 
There is a population wide deficiency of vitamin D in India, with as much as 90% of the population being deficient.
Observational studies report consistent independent associations between low serum concentrations of 25-hydroxyvitamin D (the major circulating vitamin D metabolite) and susceptibility to acute infection.
25-hydroxyvitamin D supports induction of antimicrobial peptides in response to both viral and bacterial stimuli, suggesting a potential mechanism by which vitamin D inducible protection against respiratory pathogens might be mediated.
Vitamin D metabolites have also been reported to induce other innate antimicrobial effector mechanisms, including induction of autophagy and synthesis of reactive nitrogen intermediates and reactive oxygen intermediates.These epidemiological and in vitro data have prompted numerous randomised controlled trials to determine whether vitamin D supplementation can decrease the risk of acute respiratory tract infection.
Vitamin D supplementation was found to be safe and protective against acute respiratory tract infection overall. Patients who were very vitamin D deficient and those not receiving bolus doses experienced the most benefit. [7, 8]
Green tea catechins (GTCs) are polyphenolic compounds from the leaves of Camellia sinensis. In recent decades, GTCs have been reported to provide various health benefits against numerous diseases. Studies have shown that GTCs, especially epigallocatechin-3-gallate (EGCG), have antiviral effects against diverse viruses.
Plant-derived natural products assist in the prevention and treatment of various diseases. Green tea and its major constituent polyphenols (also known as green tea catechins, GTCs) are well known for their contributions to human health, including their antitumor, antioxidative, and antimicrobial activities. Additionally, for thousands of years, green tea has been one of the most commonly consumed health-promoting beverages in many parts of the world. Epigallocatechin-3-gallate (EGCG), one of the five types of catechins and a major component of GTCs, accounts for approximately 59% of the total polyphenols in dry green tea leaves. Several other components are epicatechin gallate (ECG), epigallocatechin (EGC), epicatechin (EC) and catechin (C). ECCG is generally considered the main active constituent of green tea.
In recent years, GTCs have demonstrated inhibitory activities against various viruses, such as human viruses, livestock viruses, fish viruses, and even some arboviruses, such as dengue viruses (DENV), Chikungunya virus (CHIKV) and Zika virus (ZIKV).
Over the past few decades, GTCs, especially EGCG, have been recognized as multifunctional bioactive molecules responsible for antitumorigenic, anti-inflammatory, antioxidative, anti-proliferative, antibacterial, and antiviral effects.
In terms of the characteristics of different GTC structures, the differences in the functional properties of each catechin were associated with the number of hydroxyl groups on the B-ring and the presence of a galloyl group. Both pyrogallol and galloyl groups and the EGCG backbone itself play important roles in the different actions of different structures. Ultimately, the number and the positions of the hydroxyl groups in catechins are the most important factors influencing their activities.
EGCG is thought to be the most potent component of the catechins because of its unique structural characteristics, namely, the presence of both pyrogallol and galloyl moieties. These two groups are also essential for its antiviral activities, as both the hydroxyl group and galloyl group are necessary for the antiviral activities of GTCs.
In addition, for different viruses or different viral protein markers, the phenolic hydroxyl group and the galloyl group likely have significantly different effects on the antiviral effects of GTCs. In research on anti-HBV activity, the phenolic hydroxyl groups of EGCG on the B-ring were found to play an important role in its inhibitory effect on HBsAg, whereas the galloyl group was more important for inhibiting HBeAg.
The many previous investigations into the mechanism of action of EGCG indicate that the compound binds strongly to many molecules in cells, especially proteins, and then affects their original activities and functions. By interacting with the virion surface or cell surface receptors, EGCG can interfere with the interaction between the virions and the host cells.
EGCG plays an important role in regulating the microenvironment of endosomes and lysosomes, the acidification of which is crucial for viral invasion. Viral genome replication or viral protein expression can also be suppressed because of the inactivation of viral replicases or regulation of host factors. However, all the existing achievements have demonstrated the inhibitory effects of EGCG on the stages between virus attachment and genome synthesis. 
Sauna bathing has been linked with numerous health benefits. Sauna bathing may reduce the risk of respiratory diseases. Several studies suggest that frequent sauna baths may be associated with a reduced risk of acute and chronic respiratory conditions .
In one study, twenty-five volunteers were submitted to sauna bathing, with 25 controls abstaining from this or comparable procedures. In both groups the frequency, duration and severity of common colds were recorded for six months. There were significantly fewer episodes of common cold in the sauna group. This was found particularly during the last three months of the study period when the incidence was roughly halved compared to controls. The mean duration and average severity of common colds did not differ significantly between the groups.
It is concluded that regular sauna bathing probably reduces the incidence of common colds.
Aged Garlic Extract
Studies have shown that dietary bioactive compounds can modify proliferation of γδ-T cells. Garlic contains numerous compounds that have this potential and, in addition, has been shown to influence NK cell function.
Research suggests that supplementation of the diet with aged garlic extract may enhance immune cell function and that this may be responsible, in part, for reduced severity of colds and flu.
The effects of garlic may be due to ajoene, a derivative of allicin which displays antiplatelet and antimicrobial activities in vitro. When raw garlic is crushed, allicin is produced. Allicin has demonstrated antibacterial properties in vitro, but some studies suggest it is an unstable compound that is not detected in the circulation after ingestion. Fresh garlic is estimated to contain approximately 4.38 to 4.65 mg of allicin per gram of garlic; thus for one fresh clove of garlic, weighing approximately 4 g, there is approximately 17.52 to 18.60 mg of allicin. 
It is important to recognise that commercial garlic preparations may contain different garlic-derived compounds according to the process used to formulate the product, and that there may be substantial differences in the release of allicin from different preparations. 
The plant compounds in pomegranate can help fight harmful microorganisms. For example, they have been shown to combat some types of bacteria as well as the yeast Candida albicans.
The anti-bacterial and anti-fungal effects may also be protective against infections and inflammation in your mouth. This includes conditions like gingivitis, periodontitis and denture stomatitis.
Pomegranates have three kinds of antioxidants — tannins, anthocyanins and ellagic acid.Its seeds are the powerhouse of nutrients. Antioxidants are essential to keep cells in our bodies healthy and able to resist infections, minimise inflammations, and prevent organ damage.
Pomegranate juice contains one of the highest concentration of antioxidants naturally found — even more than red wine, concord grape juice, blueberry juice, black cherry juice, açai juice, cranberry juice, orange juice, ice tea and apple juice.
Dark Cocoa Powder
Cacao seeds can be considered a 'super fruit' and products derived from cacao seed extracts, such as natural cocoa powder and dark chocolate, as “superfoods”.
The findings presented in a recent scientific study showed dark chocolate and cocoa had more antioxidants and more flavonols than fruit juices- including supposed superfruits like acai berries, cranberries, and pomegranates.
Cocoa contains a chemical called theobromine that can help the body fight off the symptoms of the common cold. A study presented at the British Thoracic Society's winter meetings in 2012  found that the cocoa chemical blocked the action of sensory nerves in those with a cold. Blocking the sensory nerves will stop the cough reflex in a common cold. Researchers of this study found the chocolate chemical to be more effective than codeine when treating a chronic cough.
Brassica vegetables such as broccoli, cauliflower, kale and cabbage are particularly rich in a plant chemical called sulforaphane (SFN). SFN is an immune enhancing substance and young broccoli sprouts contain very high amounts of SFN.
Young broccoli sprouts have a particularly high level of SFN compared to other foods and a homogenate (or puree) of broccoli sprouts has previously been shown, in the lab, to limit the influenza virus’s ability to replicate as well as increasing natural killer (NK) cell activity, thus boosting immunity.
In a new study a daily ‘shake’ of broccoli sprouts over days seemed to protect people infected with the influenza virus for longer than a comparable ‘shake’ of alfalfa sprouts.
Over a four day period each participant was given a daily 200g ‘shake’ containing 111 g of pureed broccoli sprouts (reported to contain 100 µmol of sulforaphane) or alfalfa sprouts (said to contain “minimal” amounts of sulforaphane). This study adds to previous data showing that SFNs have a protective effect on the lungs.
 Vitamin C Infusion for the Treatment of Severe 2019-nCoV Infected Pneumonia
 Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold
 The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections.
 High-dose Intravenous Vitamin C as a Successful Treatment of Viral Infections
 Insights Into the Oral and Intravenous Administration of Ascorbate
 N-acetylcysteine improves oxidative stress and inflammatory response in patients with community acquired pneumonia
 Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data
 Study confirms vitamin D protects against colds and flu
 A Review of the Antiviral Role of Green Tea Catechins
 Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study
 Regular Sauna Bathing and the Incidence of Common Colds
 Supplementation With Aged Garlic Extract Improves Both NK and γδ-T Cell Function and Reduces the Severity of Cold and Flu Symptoms: A Randomized, Double-Blind, PlaceboControlled Nutrition Intervention
 Garlic for the common cold