A happy immune system is an important component of wellness. In light of the recent flu outbreak associated with the Coronavirus (COVID-19), the task associated with supporting immune health has become increasingly significant. Avoiding illness is not always possible, but there are several steps one could put in place to support immune health and reduce the risk of getting sick, as well as minimise duration and complications if they do.
However, across social media we’ve heard that a variety of methods including taking large numbers of supplements and strange diets can “boost our immune system” and combat against COVID-19.
Immune supportive ingredients are actually very individual and differ from person to person. There is no blanket advice when it comes to so-called ‘immune boosting’ advice. Factors involved in supporting the immune support depends very much on an individual’s genetic composition, current diet and lifestyle e.g. stress and sleep.
This article will explain why there are no single foods or supplements that will prevent or cure COVID-19, and debunk recent diet claims related to this.
How does the immune system work?
Before we dive into the details surrounding the immune system and the specific foods as well as supplements, we first need to consider how does our immune system defend our body?
People have this idea that the immune system is some kind of internal force field that can be boosted or patched up. This couldn’t be further from the truth. As the name suggests it’s not a single thing and has no central organ of control BUT is a system that involves many organs and biological functions. Their interactions defend the body against foreign invaders such as pathogens.
Each day, the body confronts an environment teeming with disease-causing organisms. The immune system is designed to implement rapid, specific, and protective responses against these organisms. The immune system can be broadly split into two parts, the innate and the acquired response.
On detection of infection, it’s the innate response that acts first. Though fast, it lacks in finesse, and deals with an invading pathogen in much the same way that the Ghostbusters might try to remove a ghost from a haunted hotel. It gunges the halls and doorways to try to flush it out (that’s why you fill up with phlegm and snot), it yanks up the thermostat to try to boil it (why you run a fever), and it shuts down the building until the problem is solved (it makes you lethargic so you don’t go out and pick up another infection while your immune system is at work).
What the innate response doesn’t do is eliminate the intruder from the body. That is the job of the acquired system, a specialised SWAT team by comparison that identifies the enemy and makes the specific weapons, or antibodies, needed to destroy it. It can takes round about 5 to 10 days for the acquired system to identify the antibodies needed and clone them up to sufficient numbers to make a meaningful attack.
DID YOU KNOW? Our immune system’s response varies over the course of 24-hours. At certain times, we may be more resilient to fighting off viruses and at other times of the day, we may be more susceptible to pathogens. For example sleep is vital for your body’s immune function the next day, so if you haven’t slept well your immune defences may be compromised.
“Immune boosting” claims are flawed
The term “boosted immune system” is unscientific and is often used in headlines and marketing of diets, potions and dietary supplements. Dietary choices and supplements don’t boost the immune system; rather it can allow the immune system to function adequately and more efficiently.
According to experts the only way to ‘boost your immunity’ is through vaccination. Getting vaccinated against the flu and other diseases stimulates the immune system to protect against illness. Vaccines teach the immune system to recognise specific pathogens and prepare them to mount a defence if they are encountered.
Therefore, our current goal (considering the COVID-19 pandemic) is to SUPPORT and OPTIMISE our current immune system with an overall healthy diet and lifestyle. For example, a balanced diet provides a range of nutrients which play an important role in our immune system.
How to optimise the immune system?
COVID-19 is a scary time for most individuals. Largely because we don’t have much data on the disease as it is brand new. Before we can make any reliable claims during this pandemic, we need repeated, robust, human clinical evidence.
However, until more research is available, we want to do our best in optimising our immune system. So, what can we do to keep the immune system functioning optimally? I would suggest the following:
- Immune supportive nutrients. A good starting point is a healthy balanced diet and to take a comprehensive, high quality multi-vitamin and mineral supplement. We should be very cautious of just taking supplements that has been touted as ‘immune boosting’.
- Correct nutritional deficiencies. Consider having nutrient levels checked by means of a blood tests in order to identify any deficiencies in key nutrients that are important to a healthy immune system activation. Supplementation can then take place according to underlying nutrient deficiencies.
- Identify and address ways to reduce inflammation. Initially we believed that anti-viral supplements were the way forward for prevention of COVID-19 and more and more evidence is emerging that the secondary focus needs to be on reducing inflammation. In fact controlling the local and systemic inflammatory response in COVID–19 may be as important as the anti-viral therapies. Taking an Omega-3 supplement is sensible since it is anti-inflammatory.
- Know your genes. Consider DNA testing. Knowing more about your genes can help your healthcare practitioner make positive changes through nutrition to improve and optimise cellular defence mechanisms.
Immune supportive nutrients: Vitamin C
There is no question that vitamin C plays a role in the immune system, however the research has found that vitamin C supplementation does not reduce the risk of the common cold in the general population.
Research has found that vitamin C supplementation did not reduce the incidence of a cold; it did reduce the duration of a cold. In adults the duration of colds was reduced by 8% (at a dosage of 1000 to 2000mg vitamin C per day) and in children shortened colds by 18%. In real terms, this works out as reducing a cold by half a day to one day.
It is also important to note that more vitamin C does not necessarily mean better. The recommended dietary allowance (RDA) is set at 90 mg/day for men and 75 mg/day for women and the upper limit is 2000mg a day. Although too much dietary vitamin C is unlikely to be harmful, megadoses of vitamin C might cause side-effects. Excess vitamin C is eliminated in the urine and may cause uncomfortable symptoms including nausea, vomiting, abdominal cramps, heartburn, diarrhoea, headache and a possible increased risk of forming kidney stones.
It is too early to make any claims related to vitamin C in the treatment of COVID-19; beyond maintaining adequate vitamin C to support the healthy function of our immune system. It therefore may be better to take lower doses of vitamin C, closer to the recommended intake and be cautious of dosages higher than 1000mg/day for prolonged periods of time. Rather focus on food sources high in vitamin C such as cauliflower, peppers, berries, oranges, mangos, broccoli and guavas.
Immune supportive nutrients: Zinc
When it comes to improving immune health, many people think zinc immediately. Although zinc does not “work” alone, it is indeed vital for supporting virtually every stage of an immune response when our bodies encounter pathogens (e.g., virus and bacteria) or dangers (e.g., tissue damage caused by oxidative stress or toxins). Therefore a deficiency in zinc may negatively impacting health. Even a mild zinc deficiency, which according to the World Health Organisation is fairly common at approximately 31% worldwide, contributes to a weaker cell-mediated immune response.
The recommended dietary allowance (RDA) for men is 11mg/day and women are 8mg/day. Unfortunately, dietary intake of zinc in South Africa has been inadequate. Older adults, vegetarians, and people with chronic inflammatory conditions or renal disease are especially at risk of deficiency. Zinc deficiency has been linked to impaired immune functions, and its clinical impact can be detrimental, such as increased susceptibility to infections including viral infections of respiratory tract, increased diarrhoea and pneumonia, impaired wound healing, and increased risk of inflammatory and autoimmune disorders.
Fortunately, deficiency in zinc can be prevented and corrected by eating foods rich in zinc such as oysters, red meat, eggs, nuts, legumes and seeds or via supplementation of zinc. Studies using oral zinc supplementation repeatedly show a significant reduction in duration of infection, such as the common cold.
Immune supportive nutrients: Vitamin D
Vitamin D is a very important nutrient for our immune system. Vitamin D stimulates the production of anti-microbial compounds (peptides) in the respiratory tract that help protect the lung from infection. According to a systematic review based on 39 human epidemiological studies, low levels of vitamin D in the blood are associated with higher risks of acute upper and lower respiratory tract infections such as flu. Maintaining healthy vitamin D levels helps support immune function in the long term. Several studies have shown vitamin D plays a positive role in reducing respiratory infections and in prevention of influenza and influenza related complications. The impact appears to be more protective in patients who are vitamin D deficient.
However, please note there are no clinical evidence showing vitamin D helps prevent or treat COVID-19 infection. Researches do suggest that a vitamin D deficiency may be tied to a higher risk of severe coronavirus infection. A lack of vitamin D could lead to immune-system complications, worsening the virus if you do get sick, one study found. Recent studies have shown an association, and not necessarily any kind of causative link. Further investigations are underway to fully understand exactly how vitamin D influences covid-19 outcomes.
While the media might suggest that you increase your vitamin D intake to protect yourself from Covid-19, I don’t think we need to push vitamin D supplementation onto everyone. If you’re already getting enough vitamin D from sunlight, food or other sources, adding MORE won’t help. In fact getting too much vitamin D can have negative side effects. Thus I’ll suggest having your vitamin D levels tested before commencing high dose supplementation. Should vitamin D levels be low, then your dietitian would be able to guide you on the dosage of vitamin D required, to address the underlying deficiency.
Correct nutrient deficiencies
Some nutrients can support the immune system but is more important when you actually do have a deficiency. Dietary deficiencies are more common than you think. A study published in the Journal of the International Society of Sports Nutrition showed that it’s really hard to get all the essential vitamins and minerals from food alone. Of the individual diets that were studied – every single diet was deficient in at least three nutrients. The most common deficiencies included vitamin D, zinc, calcium and some of the B-vitamins.
The most common deficiencies I see at Paarl Dieticians are essential fats e.g. omega-3 fatty acids, vitamin D, iron and B-vitamins. When you’re deficient in key nutrients, your physiology doesn’t work properly and you are more susceptible towards illness. Nutrient deficiencies are a well-known cause of immune system malfunction An underlying iron, zinc or vitamin D deficiency are often present and can affect the immune system dramatically and increases an individual’s vulnerability to an infection
Analysing a food record and blood testing can uncover specific nutrient deficiencies that can be corrected by means of dietary adaptations and nutritional supplementation.
Knowing your genes can help
Did you know that your genes play a large role in whether or not you will get sick? We are gifted with a complex immune system, or cellular defence mechanisms. The way these cellular mechanisms act can differ from person-to-person because of your genes. Genetic variations can cause differences in how any single part of the immune system works.
Your body’s cellular defence processes such as inflammation, oxidative stress, detoxification, and methylation are required to fight off COVID-19. (Those of you who have had their DNA tested would be well familiar with these cellular defence systems). The reaction time and how efficiently these processes respond can be adjusted using a personalised, wholesome diet, together with targeted nutrigenomics supplements.
Individuals having had their genes tested are at a significant advantage to others as they have an understanding of the cellular functioning of body systems and areas of intervention can be far more targeted. It is way too soon to know WHICH genetic variants protect against the coronavirus. However, you can test your DNA’s particular make up that is driving your immune system. Genetic testing helps explain the strengths and weaknesses of each person’s immune system.
By taking a genetic test you will then be able to tell how ready your immune system is, and whether your cellular defence processes work optimally. This will inform them what cellular processes require the most attention.
Having a healthy immune system supported by an optimally functioning cellular defence mechanism could not only give you the edge in the fight against COVID-19, but will help you live a better, healthier, and longer life.
How can Paarl Dieticians help you?
Immune support is actually an important aspect to address year-round. Lifestyle strategies, including proper hand-washing and rest, as well as personalised supplement plans, offer safe and effective ways to support a healthy immune response and reduce the risk of acute illnesses.
As there are many variables to consider, it is important to consult a specialist who can help you prepare your immune system to be strong and resilient. This is especially true in times when there is an unchecked virus on the loose. Tailor your diet and supplement plan to address individual needs. I am available for face-to-face consultations, zoom, telephone or email consultations (should you prefer to stay at home).
When you consult Paarl Dietitians, you will receive individual advice and eating plan based on your specific problem that will suit your lifestyle. Each consultation includes an individual assessment since there is no ‘blueprint’ diet that will work for everyone. We use the most up to date public health and scientific research on food, health and disease, which we translate into practical solutions and guidance to enable people to make appropriate lifestyle and food choices for healthy living. When you consult us, you are protected from misleading treatments and misinformation.
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