Written by Integrative Medical Advisory Team
Reviewed by Dr. Alex Keller, ND
What is a virus?
Viruses are particles that exploit the RNA and DNA of other cellular life forms in order to proliferate and survive. The introduction of viruses to a host promotes viral propagation by altering the host’s normal genomic and metabolic state.
Viral invasion can lead to a variety of outcomes, ranging in severity. An infection may be acute, mild, and quickly resolved by the host’s immune system (e.g., the common cold), or the infection may be severe, even fatal, and lead to chronic disease. Commonly recognized viruses may include, but are not limited to, the following:
Human immunodeficiency virus
Human respiratory syncytial virus
Varicella zoster virus
West Nile virus
How your body responds to viruses
After a viral invasion, your body’s innate and adaptive immune systems respond to the virus’ presence. A variety of cellular receptors are used to recognize when a pathogen has invaded or created byproducts that are potentially harmful to the body. This ultimately leads to the upregulation of immune, pro-inflammatory, and other products that attempt to remove or interfere with viral replication.
Current prevention and treatment approaches
Prevention of viruses mainly focuses on providing the body with a means of recognizing the pathogenic virus so that the immune system can ultimately react in a manner to disrupt viral spread. Vaccines are introduced into the body as a ‘practice run’ so that cellular receptors can effectively recognize and react to the presence of the viruses by inducing the immune system.
Unlike bacterial pathogens, viruses cannot be killed by anti-microbials, and anti-biotics are often incorrectly prescribed to address viral infection. Most viral infections do not require specific anti-viral drugs and are resolved by the body’s immune system. However, some anti-viral treatments may provide supportive functions by reducing the severity of symptoms or by suppressing viral recurrence.
What can we do to support immune function and prevent viral infections?
Foods for immune support
Maintaining a healthy and balanced diet is intricately connected to proper immune function. There are several food sources that contain anti-oxidant and anti-viral properties that may assist in providing immune system support.
Anti-oxidants prevent or reduce oxidative stress that is associated with most chronic diseases. Anti-oxidants can contribute to cellular maintenance, DNA repair, and longevity. Foods with the highest anti-oxidant profiles include berries, fruits, nuts, chocolate, and vegetables. Plant-based foods including spices and herbs also contain high proportions of anti-oxidants.
The roots of Astragalus membranaceus have been used therapeutically for thousands of years in Traditional Chinese Medicine for its bioactive polysaccharides. As demonstrated in various studies, these polysaccharides possess widespread immunomodulatory, anti-inflammatory, anti-viral, anti-oxidant, and cardioprotective activities.
In humans, Astragalus membranaceus formulations as injection or granules have been used as supportive therapy for myocarditis induced by viral infections.
Echinacea (Echinacea purpurea) is a medicinal herb widely used for its immune-boosting properties. Meta-analysis shows that echinacea use may reduce the risk of common cold development by 10-58%, and days with cold by approximately a day and a half. Echinacea may reduce the incidence of cumulative viral infections by 26% and recurring infections by 59%, including the influenza virus and parainfluenza virus. Its immune-boosting effects may be related to associated increases in immune cell counts including white blood cells, monocytes, neutrophils, and natural killer cells, which fight infection. Furthermore it may increase the suppression free radical production production in the later-phase of the cold by neutrophils. Free radicals such as superoxide may have a role in the pathogenesis of viral infections.
Black elderberry (Sambucus nigra) contains various bioactive constituents such as anthocyanins, which have been shown to have anti-viral and immune-stimulating properties. A 2019 meta-analysis showed that elderberry supplementation substantially reduced the symptoms of viral URTIs, particularly for the influenza virus.
Dosing and administration protocols have varied between published trials, but consistently improve symptoms of cold and flu, and reduce duration of infection. Two trials have shown efficacy with the administration of 15 ml (1 tablespoon) of an elderberry standardized extract syrup, four times per day to adults during meals for three to five days while children use half doses.
Another study used slow-dissolving lozenges containing 175 mg of a proprietary elderberry extract, four times per day with meals and before bed, over two days.
Finally, proprietary extract capsules containing 300 mg of elderberry extract has been provided as two capsules per day for ten days prior to air-travel, and three capsules for four to five days at the destination have been used.
Goldenseal (Hydrastis canadensis) has been traditionally used as an anti-infectious ingredient, and now used in supplements for colds and respiratory tract infections, however, there is a current lack of human clinical trials using the whole plant or an extract.
Goldenseal has been shown to inhibit the growth of influenza A and inflammatory markers in vitro. It has also demonstrated anti-microbial activity against methicillin-resistant Staphylococcus aureus and Helicobacter pylori in vitro, which are two pathogenic bacteria responsible for the development of a variety of health conditions.
One of the constituents of goldenseal, berberine, has also demonstrated anti-viral properties. In the lung cells of mice, berberine inhibited influenza virus replication and reduced the virus-induced alteration of immune cell ratios and rises in inflammatory markers.
The essential amino acid L-lysine has been used in a wide variety of applications. In relation to anti-viral therapy, L-lysine has been most studied for its uses in herpes simplex virus infections. Many trials have used doses ranging between 300-3000 mg per day for up to one year for herpes prophylaxis and symptom treatment. However, systematic reviews indicate that treatment with more than 1 gram may be required for prophylaxis or treatment of the herpes viruses, while doses greater than 3 grams per day can improve patient’s self-assessed improvements.
Similarly to astragalus, mushrooms and their active components have been extensively used in Traditional Chinese Medicine for their immune-stimulating, anti-microbial, anti-fungal, anti-tumor, and anti-viral properties.
Several in vitro studies have shown broad anti-viral effects, including anti-viral effects against influenza, using a variety of mushroom.
The herb, oregano (Origanum vulgare) is commonly used in the food, cosmetics, and pharmaceutical industries. The essential oils are now also used for their anti-microbial, anti-viral, and anti-fungal properties. Studies have assessed the anti-viral activity against certain viruses.
Though probiotics have been most widely used for their beneficial effects in the GI tract, research now shows that a healthy composition of bacteria in the GI tract can translate to improved immune function. This can also lead to improved regulation of anti-inflammatory and pro-inflammatory cytokines, and anti-oxidative biomarkers.
The benefits of probiotics can extend beyond their anti-microbial effects to also provide support against viral infections. Meta-analyses show that probiotics may reduce cold severity and have minor effects on cold prevention, as well as improve influenza vaccination efficacy for A/H1N1, A/H3N2, and B strains, but is dependent on strain and population. Meta-analyses also show the efficacy of probiotics in reducing rates of respiratory tract infections in adults and children.
10. Vitamin C
Vitamin C is one of the most popular immune support vitamins when it comes to the common cold and flu. Systematic reviews and meta-analyses indicate that supplementation with a minimum of 200 mg in children and 1 g of vitamin C per day in adults may be used as an ongoing maintenance dose to boost immunity. Increasing the dose to 1 to 2 g in children and 3 to 4 g in adults at the onset of common cold symptoms can reduce the duration of infection. This may be a result of increased anti-microbial, and immune cell activities, as well as improved anti-oxidant capacity.
11. Vitamin D
Vitamin D has been shown to be involved in modulation of the immune system due to its ability to bind to vitamin D receptors expressed throughout the body’s nucleated cells, including antigen-presenting cells within the innate and adaptive immune systems. Vitamin D insufficiencies or deficiencies have been linked to a variety of viral infections, including chronic hepatitis B, hepatitis C virus, or other viral infections leading to upper respiratory tract infections or pneumonia.
Vitamin D may also be used in the prevention and/or treatment of URTI in adults and children. One meta-analysis showed that doses ranging from 400 to 2000 IU per day over three months to three years reduced the incidence and number of events of respiratory tract infections in children and adults.
Zinc is also often recommended for its protective effect against the common cold. Zinc improves the anti-inflammatory and anti-oxidant profile. Several systematic reviews and meta-analyses show that 75 to 100 mg of elemental zinc as zinc acetate or zinc gluconate lozenges, once per day, within 24 hours of the onset of common cold symptoms, minimum 1 to 2 weeks to reduce the duration and symptoms of colds, in adults and children.
The bottom line
Viruses are particles that require a host in order to proliferate and survive. Viral infections may be asymptomatic, but can lead to mild symptoms and conditions, or more severe and chronic conditions, including death.
Practicing good hygiene can effectively reduce the risk of viral spread and infection, but maintaining a strong immune system to ensure appropriate immune responses to viral infections occur is critical. There are several best practices that can be used to support immune function, including several immune-boosting foods and supplements that may be used for their anti-viral properties.