Immune-Boosting Superfoods? Can the right diet (or supplement) protect you from COVID-19?

Nutrition and Diet

We’re all feeling a little….stressed right now. This COVID-19 outbreak is looming over every aspect of our daily lives, changing how we work, how we play, and even how we grocery shop. Anxiety levels are through the roof right now and some folks are more worried about staying healthy than they’ve ever been before.

Of course the diet and supplement industry has taken notice of people’s sudden preoccupation with health, in particular their immunity and has wasted no time promoting a laundry list of diets, supplements, and essential oils to help us ward off disease.


I’ll preface all of this by saying YES, good nutrition and general health-promoting behaviours does support a healthy immune system. That means eating a nutritious well-balanced diet, getting enough rest (hugely important), and being physically active. These practices keep us healthy in many ways and supporting a well-functioning immune system is one of them. However, we don’t actually need or want to “boost” our immune system beyond that, and in fact having an overactive immune system can be a serious health issue all in itself. Things like asthma, food allergies, eczema, lupus, rheumatoid arthritis, and type 1 diabetes are all caused by the immune system not functioning as it should, and in some cases “over reacting”. What we want is a functional, healthy immune system, not an overachieving one.

My social media feeds have been FULL of different opinions on what we should or shouldn’t be doing right now, combined with those sneaky suggestions of using this or that essential oil, or simply “cutting out sugar” to increase immunity and reduce risk of disease. Everything from Elderberry syrup to mega doses of IV vitamin C, to colloidal silver and essential oils there are thousands of posts out there claiming this or that product or diet will either prevent (or cure!) COVID-19.

Let me be the first to tell you…it’s a load of absolute garbage.

Nothing is more frustrating as a healthcare professional than seeing how quick some people are to take advantage of others during a stressful time. We’ve got a major public health event going on right now, and to see people hoarding supplies, stealing hospital stock, or buying exorbitant amounts of things to sell at an inflated price, has got me pretty disappointed in some folks. When it comes to the diet and supplement folks though, this is pretty on-brand. Disappointed sure, but certainly not surprised.

Big Media Influences

Now, when you understand a little bit of marketing strategy it’s easy to see why a public health crisis is something diet and supplement sales people absolutely salivate over. First, you create an anxiety about something, convince people they have a problem. Second, you sell people the solution to that problem. Think about this with say, the beauty industry. Without their products you’re unsightly, disheveled, unprofessional, and downright unlovable. With their products you’re glamorous, beautiful, and wanted. The anxiety surrounding not being good enough (and good looking enough) is what keeps us buying their wares. Health anxiety is like handing these marketing folks our money on a silver platter because, seriously what’s more anxiety provoking than the thought of getting seriously ill or dying? Especially now with our current collective attention focused solely on this COVID-19 outbreak, the anxiety doesn’t need to be fabricated by an advertisement, it’s already there. All these companies need to do is swoop in with their ‘solutions’.

Lacking Evidence

Most alternative therapies have pretty thin evidence to support their use as it is (why would a company spend the money to do an randomized control trial if they don’t have to?), but when it comes to anything COVID-19 related people are literally just guessing. This is a newly discovered strain of the corona virus, and scientists are still trying to figure out a lot of the basics; how easily the virus transmits from person to person, the best way to treat people who become seriously ill, and whether or not you can get it more than once. No one has had the time to do a properly designed trial to see if the keto diet is at all relevant here. Those saying that you should take this or that supplement or eat this or that food are making these suggestions based on what happens to COVID-19 in a Petri dish, not in a human body. Or they’re literally just making things up, which is all-too common as well.

So, what are some of the different diets, supplements, or alternative health products I’ve seen being touted online?

It turned out to be a depressingly long list!

Vitamin and Mineral Supplements

  • Vitamin C: Vitamin C has long been a popular “immune boosting” supplement, and is ALWAYS on the list of things to take during cold and flu season. It’s one of the most popular vitamin supplements taken in North America. Vitamin C is in fact an essential nutrient (meaning you need it to live), and it does play a role in how our immune system functions, but the question remains: is more better? is supplementing necessary if we’re getting vitamin C from foods? And the answer really depends on your current dietary habits. If you’re getting in adequate fruits and vegetables and your vitamin C intake is at least the minimum recommended amount (which is 60mg/day), supplementing with extra is unlikely to make a difference. That being said there is some suggestion that the RDA for vitamin C should be higher than where it’s currently at (upwards of 120mg/day), so getting in a few more fruits and vegetables is not a bad idea. Mega-doses or IV drips of vitamin C on the other hand can pose a safety concern so if you do decide to supplement remember this: more isn’t always better, and just because something is ‘natural’ doesn’t mean it’s safe.
  • Zinc: zinc is another essential nutrient that is key for a properly functioning immune system. In the midst of this COVID-19 outbreak, zinc lozenges have become a trendy item promoted by various alternative health sites and wellness gurus. They claim that sucking on this zinc-containing lozenges will help fight the COVID-19 virus, based on some research studies using zinc supplements to help fight the common cold (in case you didn’t know this little fact, other strains of corona virus are what can cause what we know as ‘the common cold’). However, there are no studies to date actually looking at whether or not patients who test positive for COVID-19 have had their symptoms reduced by using zinc lozenges, and while the little bit of extra zinc you might get from using these isn’t going to harm you, washing your hands and avoiding touching your face as much as possible is likely a more effective strategy.

Just, Keep It Simple

  • I’ve also seen folks peddling omega-3 supplements (a known anti-oxidant), vitamin D, vitamin A, selenium, and some others as potential preventative strategies. Getting enough of these in your usual diet (or supplementing as needed with the advice of an RD) is all you need to do. Seriously!

Alternative Therapies

  • Elderberry: elderberry (sold as syrups, lozenges, and a variety of other products) has been touted as a cure for both the cold and flu for decades. An antioxidant containing berry with active ingredients which proponents claim can “boost” the immune system, elderberry products are being touted heavily as all you need to get through this COVID-19 outbreak. Unfortunately, there are zero studies published on elderberry and COVID-19 (since this is a new strain of the virus there has definitely been no time to complete and publish any sort of high-quality trials), and even in other research settings trials are very small and sort of hit-or-miss with positive results. Will elderberry hurt you? Probably not if you’re buying a high-quality product and taking in a reasonable dose, but it’s likely a total waste of money.
  • Spirulina and Chlorella: Spirulina and Chlorella are dietary supplements made from different types of algae. They contain active ingredients which (in laboratory settings) that have anti-inflammatory and anti-oxidant effects. When it comes to legit human trials though, the evidence is scarce, and limited to a few small trials looking at things completely unrelated to viral illnesses like COVID-19. Like elderberry, it’s likely safe to take provided it is free from contaminants and manufactured by a company with adequate quality controls in place, but it probably won’t prevent or cure anything.
  • N-Acetyl Cysteine: this is a medication used to treat certain types of drug overdoses, and to loosen mucous in people with chronic health conditions (like COPD or cystic fibrosis). It stands to reason why this would be considered a treatment option in people experiencing COVID-19 symptoms, except let’s not forget that it is a drug that can have it’s own group of side effects (including nausea, vomiting, rash, and fever) and should definitely not be taken without a physician’s recommendations.
  • Colloidal silver: colloidal silver is a popular alternative therapy touted for it’s antimicrobial properties. Tons of wellness sites and alternative medicine promoters believe it can cure infections, herpes, HIV, or even cancer. And while silver does have some legitimate medical uses (when used topically/on the skin), ingesting it can lead to a condition called ‘Argyria’, which is where the skin turns a blue-grey color. Unfortunately this condition is permanent, and the discoloration does not go away when you stop using colloidal silver. Colloidal silver can also interact with the absorption of various prescription medications, so just avoid this one completely. It will do absolutely nothing to prevent or cure a COVID-19 infection and may result in you looking like a smurf for the rest of your life.

Here we go again…

  • Cleanses and Detoxes: cleanses and detoxes don’t work for ANYTHING, nevermind preventing something like COVID-19. If you do happen to catch this virus and become sick, a cleanse or detox may actually be a very bad idea. Many cleanse or detox products contain laxatives, and one of the most important things you can do during an acute illness is stay hydrated. Taking products that are going to send you running to the bathroom can quickly delete your body of fluids and electrolytes, leaving you at higher risk of your illness becoming more serious.
  • Essential Oils: team essential oil has wasted no time jumping in on the COVID-19 marketing strategy. They’re usually pretty vocal during cold and flu season as it is, so a scary new virus has just upped the ante. Popular amongst people who have a little hate-on for ‘western medicine’, an essential oils with named like “immupower”, or “on guard”, give customers the sense that these products are filled with immune-boosting and infection fighting power. It’s a complete load of crap, and a very expensive one at that considering a teeny bottle of some of these oils will cost you upwards $50.00. Save your money and just buy soap!

What about just changing your diet?

Just about every team in the diet wars has had some over-enthusiastic hero ready to save the planet by just getting us to not eat carbs. Or meat. Or vegetables (depending of course on which diet enthusiast the post is coming from). Since they’re all equally as non-evidenced based let’s just put it this way: If eliminating the risk posed to our health from COVID-19 was as simple as just not eating carbs, or meat, or fruits and vegetables, we would not have a F****** pandemic on our hands. Yes, I know you “haven’t gotten a single cold” since discovering your dietary soulmate, but these posts are unhelpful at best, seriously harmful at worst.

Are there any immune-boosting superfoods I can eat for COVID-19 prevention?

Unfortunately, no. The term ‘superfood’ is kind of bogus in general, but in particular when it comes to our immune system. Sticking to the basics is truly the best thing you can do during this time to protect yourself and others. This means washing your hands regularly, avoiding unnecessary contact with others (social distancing), especially if you are sick. Eat a nutritious balanced diet that naturally contains things like vitamin C, vitamin A, zinc, and omega-3’s, and supplement with vitamin D if you live in a region where it is recommended (like here in Manitoba). You can also support a healthy, functional immune system in other ways by getting enough sleep and staying physically active.

The Bottom Line

These are challenging times. The COVID-19 pandemic is a rapidly changing situation, with new information being shared almost hourly. The best thing we can do is follow the advice from the World Health Organization (WHO), and our local healthcare agencies and try not to let our health anxiety get the best of us, because there is always someone out there more than willing to take advantage.

Do you want to learn how to optimize your athletic performance with simple, personalized nutrition strategies? Click here to get all the details for my one on one nutrition coaching programs, and Apply for a spot! 

About the Author: Stephanie Hnatiuk is a Registered Dietitian and Personal Trainer who specializes in helping athletes reach their peak potential with nutrition.