What The Science Says

By Dr. Michelle Kmiec, OHH Founder

With much of the world focused on the coronavirus (COVID-19) threat, it isn’t any wonder that so many are literally in fear every day with the thought, am I going to get it?

We certainly all know to wash our hands frequently, practice social distancing and stay home as much as possible (especially if sick) until the pandemic is finally behind us. All of which are vital to be compliant with.


We also have been told of antivirals, such as chloroquine for example, that seem very promising to prevent the illness from becoming fatal in those susceptible. But is there anything else we all can do to boost our immune system so our bodies can fight the virus?

Well from the holistic perspective, the answer yes – and with research to support it.

But first, let me be clear. The following research is comparing the holistic remedies to viruses such as the common cold (including rhinoviruses and coronaviruses – but not COVID-19 as of yet, being a new coronavirus strain) and some different strains of influenza. However, in a time when we would all like to do all we can to boost our immune system, the following may be beneficial and worthy of investigation.

What You Can Do Holistically To Boost Your Immune System

Now I can tell you personally that I have heard many medical doctors on TV give contradictory advice on whether you should or should not take immune-boosting supplements. But before I go on, I want to be very clear. I have the utmost respect for all of the medical profession in this time of crisis.

That said, let’s explore the science behind some of the most widely used supplements and herbs and the prevention and/or shortening of the duration and severity of colds, influenza, and perhaps the novel coronavirus COVID-19.

Vitamin C

Nearly everyone thinks of Vitamin C when boosting the immune system in hopes of avoiding seasonal illnesses. But is this wisdom misguided?


Some say that the antiinfection (including antiviral) effects of vitamin C are a myth, however, this is simply not what the science indicates.

study published back in 1999 found that,

“Overall, reported flu and cold symptoms in the test group decreased 85% compared with the control group after the administration of megadose Vitamin C.”

A more recent study published in 2017 found that,

“From a large series of animal studies we may conclude that vitamin C plays a role in preventing, shortening, and alleviating diverse infections. It seems evident that vitamin C has similar effects in humans. Controlled studies have shown that vitamin C shortens and alleviates the common cold and prevents colds under specific conditions and in restricted population subgroups. Five controlled trials found significant effects of vitamin C against pneumonia.”

Another study published in 2019 concluded,

All of this evidence confirms the effectiveness of ascorbic acid against viral infections. Based on the positive outcome in this case, we propose that Intravenous Vitamin C should be studied as a vital component of the treatment protocol for acute viral infections. “

So I think it is safe to conclude that vitamin C does, in fact, play a role in boosting the immune system and helping reduce the effects of an infection, including infections from viruses.

Vitamin D

Now here is a vitamin (or hormone to be more specific) that even medical doctors on TV have gotten behind.


Vitamin D has an important role in immune function. Per a major study published in 2017,

“Vitamin D is thought to protect against respiratory infections by boosting levels of antimicrobial peptides — natural antibiotic-like substances — in the lungs. Results of the study fit with the observation that colds and ‘flu are commonest in winter and spring, when levels of vitamin D are at their lowest. They may also explain why vitamin D protects against asthma attacks, which are commonly triggered by respiratory viruses.”

They concluded,

“Daily or weekly supplementation halved the risk of acute respiratory infection in people with the lowest baseline vitamin D levels, below 25 nanomoles per litre (nmol/L). However, people with higher baseline vitamin D levels also benefited, although the effect was more modest (10 per cent risk reduction). Overall, the reduction in risk of acute respiratory infection induced by vitamin D was on a par with the protective effect of injectable ‘flu vaccine against ‘flu-like illnesses.”

Going back a bit to a 2011 study published in the Journal of Clinical Virology found,

“Newer evidence suggests that it also plays a major role regulating the immune system, perhaps including immune responses to viral infection. Interventional and observational epidemiological studies provide evidence that vitamin D deficiency may confer increased risk of influenza and respiratory tract infection.”

So along with vitamin C, vitamin D also appears to be a vital player in boosting the immune system and antiviral activity.

Elderberry (Sambucus nigra)

Another popular natural remedy used by many during the “flu season” months is elderberry. Elderberries come from a flowering plant that has long been recognized for its healing properties.

For this reason, is why you may see elderberries as one of the main ingredients in many over-the-counter cold and flu medications.

Elderberry (Sambucus nigra)

In 2019, the Journal of Functional Foods conducted a study as to the anti-influenza activity of elderberries. They found,

“Elderberry showed mild inhibitory effect at the early stages of the influenza virus cycle, with considerably stronger effect (therapeutic index of 12 ± 1.3) in the post-infection phase. Our data further support both direct effects of elderberry extract by blocking viral glycoproteins as well as indirect effects by increased expression of IL-6, IL-8, and TNF. Cyn 3-glu despite demonstrating a similar direct mechanism of action (IC50 of 0.069 mg/ml) compared to the elderberry juice, did not affect the expression of pro-inflammatory cytokines. In conclusion, elderberry exhibits multiple modes of therapeutic action against influenza infection.”

An interesting study published in 2014 found,

“These results demonstrate that S. nigra extract can inhibit IBV at an early point in infection, probably by rendering the virus non-infectious. They also suggest that future studies using S. nigra extract to treat or prevent IBV or other coronaviruses are warranted.”

So again, there does appear to be some evidence that elderberries may indeed help to boost the immune system and help against viral infections.


Echinacea, in the group of herbaceous flowering plants, is another popular remedy that pops up every cold and flu season.


study in 2011, published in Pharmaceuticals found,

Studies on Echinacea extracts have shown that some of them, but not all, possess multiple beneficial actions in the treatment of viral respiratory infections: (1) a direct virucidal activity against several respiratory viruses; (2) reversal of the pro-inflammatory response of epithelial cells and tissues to different viruses; (3) reduction in the excessive secretion of mucin by airway cells and tissues; (4) lack of cytotoxic effects or disruption of tissue integrity by Echinacea in airway cell cultures or tissues, at practical antiviral concentrations; (5) additional potentially positive effects on cellular gene expression. A combination of these beneficial activities could reduce the amount of prevailing viable virus, and their transmission, and also lead to amelioration of the virus-induced symptoms.”

An interesting 2019 article in The ASCO Post highlighted,

Preclinical studies have shown that echinacea exerts immunostimulatory and anti-inflammatory effects,1 inactivates influenza viruses,2 stimulates erythropoiesis,3 produces anxiolytic effects,4 and has wound-healing5 as well as anticancer properties.6 

Though there is evidence that echinacea can have a positive effect on the immune system and against viral infections, to be fair, it is important to also note there are many publications and studies suggesting the impact on the immune system to be minimal.


And finally, let’s discuss the trace mineral zinc.

Zinc is another one of the “big guns” in the attempt to ward off a viral attack. There was a 2019 study published entitled, The Role of Zinc in Antiviral Immunity. They concluded,


“Moreover, zinc-binding proteins such as the metallothioneins may possess antiviral roles, although their specific function remains uncertain. Nonetheless, zinc treatment applied at a therapeutic dose and in the right form has the potential to drastically improve the clearance of both chronic and acute viral infections, as well as their accompanying pathologies and symptoms. Consequently, the role of zinc as an antiviral can be separated into 2 categories: 1) zinc supplementation implemented to improve the antiviral response and systemic immunity in patients with zinc deficiency, and 2) zinc treatment performed to specifically inhibit viral replication or infection-related symptoms.”

The Journal of the American Pharmacists Association published a study in 2004 (Efficacy of Zinc Against Common Cold Viruses: An Overview). They found,

“As discussed in this report, evidence exists to support the therapeutic effect of zinc when started early in the course of a cold, ideally in the prodromal period. Pharmacists should reassure patients of zinc’s safety when used at dosages consistent with product labeling. Adverse effects are mild and are generally confined to the gastrointestinal tract. Patients should be counseled to begin zinc at the very first sign of cold symptoms, ideally within 24 hours of onset of cold symptoms. Zinc products should be continued until symptoms resolve or until otherwise advised by a physician.”

In these examples, as well as many others, it appears that zinc is important to immunity and can have a positive effect on the duration and severity of symptoms regarding viral infections.

The Bottom Line

Having a strong immune system is something that should be at the forefront of all of us – all year long. But sometimes even when we do the best we can, events in life can throw us off our game and weaken our immune system. One of the biggest contributors is stress. So it is not a bad idea to ensure that your immune system is getting all the help it can by eating healthy foods, exercise, and enjoy the outdoors weather permitting. But in times of stress, supplementing with immune-boosting remedies just may be the ticket.