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Diet and supplements: Swiss expert panel publishes new COVID-19 guidelines and calls for immediate action

Diet and supplements: Swiss expert panel publishes new COVID-19 guidelines and calls for immediate actionA panel of physicians and professors collaborating with the Swiss Society for Nutrition (SSN) recently reviewed the scientific evidence on the role of micronutrients in supporting a well-functioning immune defense for optimal health with particular focus on viral infections related to COVID-19. They conclude that there is widespread lack of vitamin C, vitamin D, selenium, zinc, and omega-3 fatty acids, all of which are crucial nutrients for the immune system. These deficiencies contribute to new waves of COVID-19 and can cause the infections to become life-threatening. The panel calls for immediate action with relevant focus on diet and supplements.

New waves of the COVID-19 pandemic continue to threaten public health, quality of life, and the economy. A Swiss expert panel consisting of doctors and professors from the ETZ Zürich, University Lausanne, University Groningen, and the Swiss Society for Nutrition (SSN) recently published a white paper that notes that the global pandemic has made nutrient status and immune support particularly relevant. This is because the Swiss population is at risk of a partial or severe lack of micronutrients that support the immune system.
The panel of experts emphasizes the importance of getting the nutrients from a healthy, balanced diet. However, things look different in reality because modern diets, nutrient-depleted soil, too little sun exposure, ageing, and other factors make it difficult for many people to obtain enough of the different vitamins and minerals.
It may therefore be necessary to take different supplements to help strengthen and control the immune defense. COVID-19 infections can turn into a serious threat when the immune system overreacts with hyperinflammation and cytokine storm that damages healthy tissue. It is the capacity of the immune system that determines whether we are able to fight off the infection, whether we have mild symptoms only, or experience life-threatening complications that require hospitalization. The Swiss panel makes it clear that it is vital to get enough vitamin C, vitamin D, selenium, zinc, and omega-3.

Vitamin C

Vitamin C is highly important for the innate immune defense that functions as the body’s storm troops. The innate defense mechanism is able to tackle most harmful microorganisms without us even noticing it. In the case of an acute infection such as a cold, influenza, or pneumonia, blood levels of vitamin C drop, causing an immediate need for the vitamin. The experts therefore recommend supplementing with 200 mg of vitamin C daily to help prevent and fight infections. Supplements with higher doses are available. It is a good idea to choose products with non-acidic vitamin C sources such as calcium ascorbate that are gentle towards the gastric mucosa.

Vitamin D

It is not a coincidence that we experience new waves of COVID-19 during the winter period. It is because of the widespread lack of vitamin D. At northern latitudes, our skin can only produce vitamin D in the summer period where the sun is sufficiently strong. People who spend nearly all their time indoors, nursing home residents, dark-skinned individuals, seniors, overweight people, and diabetics are at risk of a vitamin D deficiency and are therefore particularly vulnerable.
Vitamin D activates the innate and the adaptive immune defense that is able to specialize and form immunity. Vitamin D also helps regulate several pro-inflammatory cytokines (IL-2, IL-6, IL-8, IL-12, IL-17, TNF-alpha, IFN-gamma, and NFkBA). It is vital for the body to be able to fight an infection by launching an acute inflammatory response that is tightly controlled. But if the body lacks vitamin D, the innate and adaptive immune systems are unable to perform properly. This increases the risk of infection and uncontrolled inflammation, which has the potential to damage healthy lung tissue and cardiovascular tissue.
A new meta-analysis (Martineau et al.) recently reported that vitamin D supplements reduce the number of acute respiratory infections by up to 42 percent.
Over the course of the COVID-19 pandemic, more than 1,500 scientific publications have addressed vitamin D’s vital role for immune health.
The Swiss expert panel recommends daily supplementation with 50 micrograms of vitamin D. Because the ability to utilize vitamin D varies from person to person, some scientists recommend taking up to 100 micrograms per day, which is also the safe upper intake level for vitamin D.


Selenium supports a number of different selenoproteins that are relevant for the immune capacity and immune cell communication, especially with relation to fighting respiratory infections. The selenium-containing GPX antioxidant enzymes (glutathione peroxidase) protect the body against oxidative stress and excessive inflammation. Selenium also prevents virus from mutating and becoming increasingly virulent.
Because the farmland in Europe and many other places in the world is low in selenium, it is believed that around one billion people worldwide lack this micronutrient.
Science has discovered a link between selenium deficiency and increased severity of viral infections such as Keshan Disease, coxsackievirus B3, and influenza A. Also, there is a higher COVID-19 mortality rate among selenium-deficient patients.
Due to the fact that most European populations get too little selenium, the panel recommends taking 50-100 micrograms of selenium per day. Several studies suggest that most people need around 100 micrograms of selenium per day in order to properly saturate selenoprotein P, a specific selenoprotein that is used as a marker to gauge the body’s selenium status. Selenium yeast is ideal for supplementation because it contains the same variety of different selenium species that you get from eating a balanced diet with many different natural selenium sources.


Zinc is important for the innate and the adaptive immune defense, including the T cells and a number of different proteins that are involved in inflammatory processes. Zinc also supports the powerful SOD (superoxide dismutase) antioxidant that counteracts oxidative stress. Zinc helps stabilize the cell membranes against virus attacks, and zinc-containing proteins code around 10 percent of our genes to enable them to carry out their different tasks.
A zinc deficiency can weaken cell membranes and cause the immune system to malfunction, making us more susceptible to infections and inflammation.
An estimated 30 percent of nursing home residents lack zinc, compared to about five percent of seniors living at home.
Lack of zinc increases the risk of hospitalizations and various complications. Several studies suggest that zinc supplementation has the ability to improve the immune system, especially among older people. A possible reason for this is that the ability to take up zinc decreases with age. Also, many older people eat very little. Furthermore, regular use of diuretics may increase the need for zinc, as the nutrient is excreted via the urine.
There is also a number of studies showing that zinc supplementation should be initiated in the early phase of a respiratory infection.
The Swiss panel recommends taking 10 mg of zinc each day. According to the European Food Safety Authority (EFSA), the safe upper intake level for adults is 25 mg.


EPA and DHA are two omega-3 fatty acids that we have in our cell membranes, where they are involved in a host of biochemical processes. EPA and DHA lower the body’s levels of CRP (C-reactive protein) and the cytokines TNF-alpha and IL-6, both of which are inflammation markers. You get EPA and DHA from oily fish and fish oil supplements. It is best if you eat fish from clean and pure waters. The expert panel recommends getting 500 mg of EPA and DHA per day to reduce the risk of inflammation. Fish oil based on free fatty acids is easily absorbed in the digestive system. Make sure that the fish oil supplement you take complies with the official threshold values for peroxides and environmental toxins.


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