Should we be using nutritional supplements during the Covid19 pandemic?

Written by Dr. Andri Philippou RD

10 February 2021




Of course social distancing and regular sanitising or handwashing are by far the most proven methods of reducing risk and spread of COVID-19, but many people have come into our offices wondering about the particular role that diet and nutrition may have in reducing risk of COVID-19.

Generally we refer to a healthy diet (for individuals with no other pre-existing medical conditions) as one rich in vegetables, fruit, whole grains, legumes, nuts, moderate in fish, dairy and poultry, and limited in red/ processed meats, refined carbohydrates and sugar. Fats should be mainly liquid fats ie. olive and canola oil. A diet with this mix will provide adequate amounts of healthy macronutrients and essential vitamins and minerals to ensure sufficient levels of immune cells and antibodies – important soldiers for the body to fight infection.

Although we have no data on the role of nutrition and its specific impact on COVID-19 risk and progression, we do have some excellent existing evidence on the role of nutrition in mitigating effects in other similar infections.


Inadequate zinc levels limit a person’s ability to produce a strong enough immune response to an infection. Existing studies have shown that oral zinc supplementation reduced the incidence of acute respiratory infections by 35%, reduced duration of flu-like symptoms by roughly 2 days, and improved rate of recovery from infection.

Dose: Studies varied from 20mg/ week to 92mg/ day showing that dose does not drive the effectiveness of zinc.

RDA: 12-15mg/ day

Food sources: meat, poultry, fish, seafood, organ meat, wholegrains (quinoa, brown rice, rolled oats, wholegrain bread, pasta), dried beans, peas, lentils, nuts (pine, peanuts, brazil) and seeds (pumpkin, sunflower and chia).


Acts as an antioxidant limiting inflammation and tissue damage associated with any immune response. In patients admitted for a wide variety of conditions (sepsis, postoperative complications, burns, lung damage and cardiac conditions), existing studies showed that vitamin C reduced the duration of ICU stay, the need for mechanical ventilation, and the incidence of respiratory tract infections.

Dose: Studies varied from 1-3 g/day and again dose did not seem to drive the effectiveness of vitamin C.

RDA: 500 mg/ day (never more than 2000 mg/ day)

Food sources: Citrus fruits (oranges, lemons, grapefruit), kiwi, strawberries, mangoes, papaya, peppers, broccoli, brussel sprouts, tomatoes, raw dark leafy vegetables and potatoes.


Beneficial effect of supplementation in existing studies was seen across all ages and in individuals with pre-existing chronic illnesses. Supplementation was found to lower risk of developing acute respiratory tract infections (mostly due to viruses) by 12-75%, and to reduce flu symptoms in those that were already infected.

Dose: Studies showed response with doses > 1000 IU/ day.

RDA: 400 IU/ day

Food sources: Fortified milk and soy rice beverages, fortified margarine, salmon, snapper, trout, halibut, eggs, organ meat, fish liver oils.



Immunomodulation refers to changes in the immune response or the functional immune system as a result of the action of a substance that affects the functioning of the immune system. Probiotics (beneficial live microbes of humans and animals) have well been established as immunomodulatory tools applied for modifying the human immune response.

A recent study conducted in China confirmed that COVID‐19 infection affects the balance of natural microbiota in the human intestine, while authors of another study in China found that most of the patients with relatively mild symptoms had received probiotics along with the established treatment protocols. It has also been reported that COVID-19 can cause severe hypoxemia and changes in the balance of gut microorganisms. While these all tend to lean towards a positive impact of probiotics in the management of COVID-19, and although the healthful, functional, nutritional, and immune benefits of probiotics and prebiotics are scientifically well established beyond a reasonable doubt, including their roles in fighting some viral infections such as seasonal virus infections, their specific potential biological roles against COVID-19 infection still warrant further clinical and laboratory investigation.

We recommend you take a “Coated” probiotic supplement as this is the safest way for the good bacteria to reach your small and large intestine in the right quantities.

Food sources of probiotics: Yoghurts, kefir, fermented foods like sauerkraut, pickels, kombucha, buttermilk and cheese like cheddar, mozzarella and gouda.


COVID-19 symptoms typically include fever, cough, fatigue, headache, diarrhoea, interstitial pneumonia (which can lead to acute respiratory distress syndrome), sepsis-induced coagulopathy and multi-organ failure. In addition, during the progressive stages of COVID-19, intense cytokine storms with excessive production of pro-inflammatory cytokines are evident.

Adequate levels of vitamin B is known to manage your immune response by downregulating pro-inflammatory cytokines and inflammation, to improve respiratory function, to maintain endothelial integrity, to prevent hypercoagulability, to play an important role in cell functioning and energy metabolism, to enhance immune function, and to reduce length of stay in hospital.

With this in mind, vitamin B status should be assessed in COVID-19 patients, and further studies are underway to determine whether vitamin B (and what recommended doses) could be used as a non-pharmaceutical adjunct to current treatment protocols.

In today’s stress life and because many people are one some sort of chronic medication for diabetes, cholesterol and high blood pressure we recommend a good general Activated B – Complex supplement.

Food sources of B vitamins: Leafy greens, salmon, liver, eggs, milk, beef, oysters, clams, mussels, legumes (beans and lentils), chicken, pork and brewer’s yeast.


• A standard multivitamin/ multimineral supplement is a great way to provide a nutritional safety net – containing both Vitamin C and zinc.

• Maintaining adequate levels of Vitamin D is important – +1000IU supplement or expose as much skin as possible in the middle of the day for roughly 15 minutes (3 0r 4 times longer will likely be needed for darker skin).

You can ask us which specific products we recommend for adequate intake to supplement your healthy diet and to take care not to overdose. We will do a free vitamin analysis with your consultation with your dietitian.