Build your immune resilience – as nature intended


The information in this article is for educational purposes only and should not be construed as medical advice. If you are experiencing any symptoms of illness, or consider that you might have been exposed to the coronavirus, follow the advice of your health authority [the UK’s NHS advice is fairly detailed and useful wherever you may live]. This will typically mean staying at home and avoiding close contact with other people.

Do not go to a GP surgery, pharmacy or hospital and, in the UK, use the NHS 111 coronavirus service to get advice on what to do.

Original article posted on 12 March 2020

Maintaining health also means maintaining the right balance between host and pathogens.

We attempt to do this unconsciously on a daily basis given the sheer number of microbes we’re exposed to from the air we breathe, the food we eat, the ground we walk on and the things we touch. A large majority of these microbes are friendly, beneficial even, but some most definitely are not if they start developing in significant numbers. Sorting friend from foe is exactly what our immune systems are there to do. Our innate and adaptive immune responses evolve during our lifetime. Constantly learning and adding more information to the ‘memory banks’ so that the right weapons can be manufactured in time to destroy whichever foe has been identified before it can destroy us. Our gut microbiome plays an integral and essential role in maintaining proper immune defence and essentially governs immune resilience.

The extreme ingenuity of our part-human, part non-human immune make-up has got us this far in evolution. Integral to this is understanding that what we eat and how and where we live provided the basis for this millennia-long co-evolution of our immune systems, both with the microbial and non-microbial worlds within and around us. It’s all we had at our disposal to modulate and support our immune systems for the majority of our own species’ evolution. Despite the advances of modern science and medicine, nutrition and lifestyle interventions are still one of the most powerful ways to ensure the resilience of your immune system. Despite the incredible sophistication of immunological processes, and a deep knowledge of things we can do to modulate our immune system to our advantage, somehow we tend to put managing our immune resilience on the backburner. We assume there’s not much we can do to improve it, which is just plain wrong.  What’s more, the kinds of things we can do to enhance immune resilience tend to be cheap, practical and largely within the remit of our own self-care.

Surely that’s helpful when the world is gripped by fear over the consequences of infection by the new coronavirus, COVID-19 (the subject of our special report released today). Apart from behavioural measures designed to reduce transmission, the primary interface between us and the new coronavirus is our immune systems.

Supporting immune resilience naturally

Following are our top 10 picks for immune system support, naturally. However, this is definitely not an exhaustive list nor the only beneficial natural immune support available.

  1. Food is medicine. It’s also information for your DNA and your immune modulation. Fundamentally, food provides thousands of individual naturally occurring substances that help our bodies perform optimally. Our nutrition requirements change as we go through different times in our life and particularly when our immune system kicks into action and needs to protect us. At times of high demand, paying attention to food quality is paramount. Eating a diverse range of fresh, preferably whole, unprocessed or minimally processed plant foods helps to provide all-important phytonutrients to arm our defences. Fresh herbs (e.g. garlic, rosemary, sage, oregano) and spices (e.g. turmeric, black pepper, saffron) are especially polyphenol-rich to support modulation of the immune system, as well as being anti-inflammatory. Adapting what we eat, the way we prepare it and using targeted supplements to support immune function is safe and effective. Antibiotics are no use against viruses. Your immune system and your internally-generated ‘chemical warfare’ remains the best defence. Consume a nutrient-dense diet following the 10 pointers as per our Food4Health guidelines.

  1. Zinc was discovered as a critical element in the functioning of the immune system of mammals, including humans, in the early 1960s. Newer research has demonstrated that zinc’s key mechanism of action in the immune system is by stimulating serum thymulim (a thymus specific hormone involved in T cell function) and through modulation of T helper cell functions, which coordinate our entire adaptive immune system response. Conversely, immune function is compromised with zinc deficiency, which is becoming more widespread as we eat fewer zinc-rich animal foods. Many of the soils on which animals are farmed or animal feeds are cultivated are now depleted. Significant amounts of zinc now come from fortified foods like breakfast cereals, however, this is often not well-absorbed because it is bound to phytic acid in grain-based foods and excreted. Many adults are sub-optimal in zinc, and a recent UK dietary survey found 5-30% of most adults (18 and over) are chronically deficient. Therefore, taking 25-50 mg per day of supplemental zinc in a bioavailable form may help to modulate cytokine activity (chemical messengers) and to stimulate the activity of natural killer cells and T-cell precursors. Don’t take zinc supplements with grain-based foods to avoid binding with phytic acid. Consider taking it in liquid or lozenge form between meals.

  1. Vitamin A is essential for normal growth, for cell maturation, particularly neurodevelopment; for cell membrane stability, for visual and skin health, as an antioxidant, as well as for immunity. Vitamin A is needed for the normal functioning of both the innate and the adaptive immune response. Being deficient in vitamin A (retinol) can severely impair immunity and lead to increases in illness and death because it’s so integral to all aspects of immune defence. Many people are deficient in vitamin A because they consume few foods that are rich natural sources of preformed vitamin A like liver, fish, cheese and eggs. They also may not consume sufficient provitamin A carotenoids that are converted, somewhat inefficiently and variably to vitamin A in the body. These provitamin A carotenoids, hundreds of which have been identified and beta-carotene is just one, are especially abundant in red, yellow and orange vegetables and fruit. In diets low in vitamin A (retinol) or provitamin A (carotenoid) food sources, retinol supplements (e.g. retinyl palmitate) should typically provide 800 – 1,500 mcg retinol equivalents (RE) per day, but this might double for 2-3 days during an immune challenge. Vitamin A should always be taken at a different time to vitamin D because they can be functionally antagonistic.

  1. The role of vitamin C (ascorbic acid, ascorbate) in fighting infectious diseases became well known (and controversial) with the publication of Dr Linus Pauling’s book, ‘Vitamin C and the Common Cold(1970), which advocated vitamin C megadoses (grams, not milligrams daily). Vitamin C is indeed a powerful antioxidant against a large number of free radical species, but it also functions as a cofactor for enzyme reactions. Interestingly the antiviral effects of vitamin C may be down to it also acting as a pro-oxidant when the need arises, such as in the case of cancer or viral infections. Healthy cells tend not to be affected by this pro-oxidant effect, but viruses and cancer are, which is why intravenous vitamin C is used to deliver large doses to affected people. Maintenance doses for general immune health are typically in the region of 250 – 500 mg per day. When immune challenged, divided doses can be used to deliver 2-3 grams per day in total. The primary adverse effect from higher doses of vitamin C is a loose bowel, but during a viral infection, the vitamin C requirement increases so that higher doses can be tolerated without bowel symptoms.

  1. Clinical experience and research by leading vitamin D researchers Professor Michael Holick and Dr Reinhold Vieth have consistently shown levels of 100 mcg (4,000 IU) or more of vitamin D3 (cholecalciferol) need to be taken orally to deliver optimal circulating levels of 25-hydroxyvitamin D (25(OH)D). Optimum levels of 100-150 nmol/L (40-60 ng/ml) have been determined by a group of leading vitamin D researchers that have come together under the banner of Grassroots Health. Clinical experience has shown, short-term, that levels around 10-fold greater than this can be used where bacterial or viral infections have taken hold. These very high intakes should be managed under health professional supervision and should not be maintained for more than a week, before returning to levels of 250 mcg (10,000 IU) or less. High dose vitamin D should be accompanied with regular measurement of circulating 25(OH)D as there can be big differences in amounts required by individuals to optimise circulating levels. It’s generally assumed that the prevalence of colds and flu during the winter months is caused by the cold weather. However, inadequate sunlight and resulting vitamin D deficiency are likely underlying causes of the ‘flu season’, an argument first put forward with accompanying evidence back in 2008 in the journal Virology by Professor John Cannell and colleagues. Additionally, most will benefit from taking supplemental magnesium (at least at the recommended daily level of 375 mg/day) given how many people are deficient in magnesium from their normal diets as it’s required for vitamin D activation.

  1. Nucleotides are less well known, but nonetheless an important emerging group of ingredients that have great potential for improving the modulation of our very complex immune systems. Nucleotides, being the basic building blocks of DNA and RNA, are fundamental to all life. They’re also not new. Evidence suggests they were among the chemical compounds that helped kick-start life in the ‘primordial soup’ over 4 billion years ago. Every new cell requires nucleotides. DNA holds the genetic code, while RNA is responsible for the translation of information from the genetic code to the production of proteins which make everything happen in our bodies. Nucleotides are in especially high demand when the immune system is upregulated given the rapid and increased turnover and replication of cells. Being so essential, our bodies can make nucleotides or salvage them from dead cells, but when demand outstrips supply (infections, stress, exercise, gut repair, injury), we must take them in from food sources. The most concentrated sources are organ meats and offal, which are increasingly rarely consumed in the modern, especially Western, diet. They are also quite abundant in fermented foods, such as properly fermented tofu, tempeh and natto. Mirroring what was likely to be normal dietary intake of around 500 – 1500 mg of nucleotides for much of human evolution, these amounts can be consumed from nucleotide-containing food supplements to ensure you have a daily supply. If you can, source a pyrimidine dominant nucleotide supplement to best mirror nature. Very high intakes of purine-based nucleotides can be an issue for those susceptible to gout (i.e. high circulating uric acid), but this is rarely an issue at typical supplemental doses.

  1. Andrographis paniculata is a herb with a long history of use in both Ayurveda and Traditional Chinese Medicine. When looking at what it’s been used for traditionally, it appears to be a kind of panacea, but it’s especially well known today for treating viral infections, particularly of the upper respiratory tract, and relieving cold and flu symptoms. The bitter herb is a powerful immune modulator, down to the andrographolides in the plant which are thought to enhance the production of white blood cells, to support the release of interferon, and to promote the healthy activity of the lymphatic system. Andrographis is also anti-inflammatory and pain relieving, whilst having a supportive action on the liver in much the same way as milk thistle. Given the rising spectre of antimicrobial resistance, last year, Southampton University embarked on a trial to evaluate the effect of an Andrographis product made by the organic herbal company, Pukka Herbs, to assess whether it might be effective in treating acute upper respiratory tract infections. The results are due to be published in the near future and provisional results released at a meeting at Chelsea Physic Garden last October were very positive. Relatively, it’s an inexpensive supplement, and a typical dose during an immune challenge is around 500 mg dried Andrographis leaf, twice a day.

  1. Beta-glucans are one of the best documented and most effective natural group of compounds known to enhance the function of the innate immune system. Particularly, the beta 1-3/1-6 glucan, generally derived from brewer’s yeast (Saccharomyces cerevisiae), or found within mushrooms such as shiitake and maitake. Mushrooms may be a bit like Marmite – you either love them or hate them – but more than 50 species have been found to be ‘immunoceutical’ hot houses. If you loathe eating mushrooms, you can still benefit from their immune power by taking a food supplement. Macrophages, the clean-up cells of our immune system, have receptors that specifically recognise beta 1-3/1-6 glucanbecause they occur in the cell walls of many bacteria and fungi. Consumption of beta 1-3/1-6 glucan has been shown to amplify the immune response of immune effector cells such as macrophages, dendritic cells, natural killer cells and cytotoxic T-cells in animals and humans. Beta-glucans are best taken on an empty stomach in the morning in typical doses of 700 – 1500 mg. You can also use a body weight calculation of 2 mg beta 1,3/1,6 glucan per kg body weight for general maintenance.

  1. Echinacea preparations from Echinacea purpurea and E. angustifolia are one of the most widely used herbal products for the common cold, in both Europe and the USA. Studies have shown that dried leaf and root powders acted as potent immuno-stimulants in murine and in vitro tests, while fresh juice extracts or extracts standardised to phenolic acid or echinacoside content were relatively inactive. However, it appears from a review of 13 randomised, double blind, placebo-controlled trials that Echinacea may be more effective in treating the early symptoms of common cold, than in its prevention. Caution should be observed with regard to dosing as higher dose Echinacea can upregulate TNFacytokine, which is one of several cytokines associated with serious disease and cytokine storm in COVID-19. Probably the continued use of Echinacea during infection is not advised.

  1. Curcumin from turmeric (Curcuma longa) is king amongst spices. Hailed as ‘the spice of life’ turmeric/curcumin has been used for thousands of years in traditional medicine. Every house should have a stock of both the fresh root (keeps well in the freezer, grate when needed) and dried turmeric powder (non-irradiated if possible). Curcumin may be one of the most studied components of turmeric root, but using the whole root or supplements containing the full-spectrum of carcuminoids rather than just isolated and concentrated curcumin, likely allows for better synergy and a wider array of benefits. Full spectrum turmeric products and the fresh root also contain small amounts of volatile turmeric essential oil that enhance bioavailability and absorption.

The diverse range of health benefits of turmeric are linked to its multi-target activity in the body, and so include: immune modulation, anti-viral, anti-inflammatory, antioxidant, anti-microbial, anti-tubercular, cardio-protective, anti-diabetic, hepato-protective, neuro-protective, nephron-protective, anti-rheumatic, and anti-cancer effects. It’s fair to say that turmeric, and its active components, likely have an action on every cell in the body and benefit every process in the body. It’s truly medicinal food. Whilst there are many curcumin and turmeric supplements to choose from on the market, it’s very versatile in the kitchen and can be used in both sweet and savoury dishes, as a tea, herbal root infusion or enjoyed as ‘golden milk’ – the now famous ‘turmeric latte’. In India, consumption of turmeric root is typically around 2 to 4 grams per day in food. Good food supplements usually provide 500 mg capsules with a standardised amount of curcumin, alongside other curcuminoids and the essential oil (or other bioavailability enhancers). Daily dose targets should be 1000 – 1800 mg per day taken in 3 doses alongside food during immune challenge.

Is your immune system pandemic-ready?

There is ample evidence that human immune-competence is strongly related to nutrition, physical exercise and psycho-social stress. Through much of the Western world,  there is a dearth of evidence-based nutritional and lifestyle advice and recommendations being communicated to citizens. This is especially risky when there are already rogue players with inferior or ineffective products trying to capitalise on the ‘opportunity’ provided by COVID-19.

A recent systematic review on alternate COVID-19 treatment strategies in China has found that the immune response is weakened by inadequate nutrition and they are proposing that the nutritional status of patients should be assessed before any drug treatment begins.

Nutritional and lifestyle patterns during a pandemic could actually negatively affect immune function. Food quality may deteriorate as people rush to stock up on packaged, dry and tinned goods. People may be more stressed and sleep less well because of the impacts on their home or working lives. This is not what the immune system needs if it’s to be resilient and defence-ready. Maintain your supply of fresh foods, use box (CSA) schemes which deliver organic or from the farm-gate to your door, get lots of sleep, stay connected with your tribe even if it means doing so electronically and not in person, and remember that targeted supplementation can be helpful to counter micronutrient deficiencies and provide enhanced immune support.

While many might be spending a little less on travel given the need to reduce transmission risk, it may be one of the best times to invest more in your own health. Booking an appointment with a health professional, such as a functional medicine, nutritional or herbal practitioner, may not be what your doctor (GP) has ordered, but it makes sense.  A resilient immune system is one that responds appropriately to challenge and then turns off when the foe is vanquished. It allows us to become ill, but get better again in a shorter time frame, often with fewer and less pronounced symptoms. There is also a silver lining: a less naïve, and even more primed immune system for any subsequent exposures to the same pathogen.


The information in this article is for educational purposes only and should not be construed as medical advice. If you are experiencing any symptoms of illness, or consider that you might have been exposed to the coronavirus, follow the advice of your health authority [the UK’s NHS advice is fairly detailed and useful wherever you may live]. This will typically mean staying at home and avoiding close contact with other people.

Do not go to a GP surgery, pharmacy or hospital and, in the UK, use the NHS 111 coronavirus service to get advice on what to do.