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Nutrition for a Resilient Immune System: My Top 6

In these times of uncertainty, we want to be doing all we can to harness the might of our immune system, and optimising our nutrition is one way to help improve our resilience to illness.

Our immune system is constantly working to protect us from infections and illness.  It is a complex system which, when out of balance, suppressed or overstimulated, is unable to function optimally.  White blood cells are continuously on guard looking for pathogens, and T-cells help to coordinate immune regulation and kill compromised cells.  T-cell function does decline with age, leaving older people more susceptible to infection and illness, and immune support for this sector is therefore highly relevant.  It is paramount at any age however to support the immune system with good nutrition and lifestyle practices. Unhealthy lifestyle choices compromise immunity and make us all more susceptible to disease.

Certain life practices can deplete nutrients, most notably a high intake of alcohol leaches B-vitamins, chronic stress impacts upon magnesium, vitamins B and C, smoking depletes vitamin C, and processed foods and cooking methods affect the nutrient content of our food.  Nutritional needs change at different stages of life and when we are going through illness. Prolonged infection depletes vitamin C, effectively creating an increased need therefor, and our tolerance for this vitamin becomes higher.

So, what are my top six priorities for building a strong immune system:

  1. Firstly, avoid sugar, processed foods and refined oils – these create inflammation in the body – confectionery, white flour and grains, cakes, pastries, pasta, fizzy drinks, etc. Whole grains such as rye, brown rice, buckwheat, quinoa are superior choices.  A little dark chocolate 85% cocoa and above is an acceptable treat as it is super-rich in antioxidants!  TIP: A whole dried fig or Medjool date can help satisfy sweet cravings.  The fibre they contain will help prevent unwanted blood sugar spikes.


  1. Eat more plants! Plants contain phytochemicals – these wonderful colourful pigments protect you against inflammation and cell DNA damage. Plants are packed with vitamins and minerals that your immune system needs to function.  Plants also contain fibre that the gut metabolises to make things called Short Chain Fatty Acids that have antioxidant effects and support the immune system.   TIP: Batch-make vegetable soups and broths to consume daily – they will last up to 5 days in the fridge, or keep some frozen.


  1. Look after your microbiome! There has never been more interest in the health of our gut microbiome and its role in immunity.  Again, our diets are key to keeping the bacteria in our guts in balance; modern, processed diets high in sugar are the enemy!   (Of course, antibiotics have to top the list for microbiome damage, and attention to the gut after antibiotic therapy is crucial, with probiotic supplements probably benefitting most people.)  Feed the microbiome with fibre from vegetables, fruits, beans, lentils, herbs, nuts, seeds, whole grains and fermented foods such as sauerkraut, kimchi, miso and kefir.  Your gut will also thank you for increasing your range of colourful foods and diversity of foods. TIP: Add a teaspoon of unpasteurised miso to your daily bowl of soup.


  1. Eat the rainbow every day! This will help to ensure you are achieving a good daily intake of immune-boosting micronutrients – Red: tomatoes, watermelon, pomegranate; Orange: sweet potato, carrots, apricots; Yellow:  bananas, bell pepper, pineapple;  Greens: Peas, kale, rocket, spinach; Blue/indigo: blueberries, blackberries, black grapes; Purple: plums, red grapes, red cabbage.  Don’t forget onions, garlic, herbs and spices daily – all have proven health properties.  Just small amounts (preferably organic) of different colours, will benefit your health. Diversity is key. TIP: Keep a chart of the number of colours eaten daily and aim to reach a full rainbow – involve the kids.


  1. Optimise Vitamin D levels. Vitamin D enhances natural immune response as well as being anti-inflammatory.  Synthesised in the skin by the action of UV sunlight, it is no surprise that most of us living in northern climes are low or deficient, especially in winter.  Very few foods in nature contain vitamin D but the highest is oily fish (e.g. mackerel, salmon, tuna), so non-fish eaters are at greater risk and almost certainly need to supplement.  Egg yolks, beef liver and cheese also have small amounts. Public Health England recommends that adults and children over age 1 should consider supplementing 10 mcg per day in autumn and winter and, those at higher risk, all year round.  Anyone taking cod liver oil supplements will be getting vitamin D (and A).  I encourage testing and monitoring for many of my clients, especially those over 60 and those with chronic illnesses.  TIP: keep tinned fish on hand e.g. sardines for lunch.


  1. Optimise intake of these nutrients – there is some good evidence for the role of certain nutrients in supporting the immune system.
  • Vitamin A: top food sources – liver (not in pregnancy, or planning thereof), fish, beef and eggs. For vegetarians, beta-carotene, found mainly in orange, yellow, red and green foods (e.g. mango, carrots, spinach, peppers) can be converted in the body to vitamin A
  • Vitamin C: fruits and vegetables especially bell peppers, citrus, kiwifruit, broccoli and strawberries
  • Vitamin D: oily fish. A little in egg yolks, beef liver, cheese, and mushrooms exposed to sunlight
  • Zinc: shellfish, beef, baked beans, pumpkin seeds, nuts, yoghurt, chickpeas, oatmeal
  • Selenium: Brazil nuts, fish, turkey, cottage cheese, chicken, mushrooms
  • Beta glucans: Mushrooms are an absolute superfood for the immune system and support T Cell function, particularly Reishimaitake and oyster varieties – a daily intake of mushrooms of any kind is recommended. Yeast, oats, barley and seaweed also contain beta glucans.
  • Pre and probiotics: Fruits, vegetables and whole grains for their fibre content fermented foods – yoghurt, kefir, kimchi, sauerkraut, miso

TIP:  Make colourful fruit smoothies (using fresh or frozen) and add: yoghurt, nuts/seeds/oats

These are just some of my top tips for immune support.  I am unable to delve deeply into the specifics of supplements/doses outside of a clinical consultation.  However, a good multivitamin and mineral supplement will not go amiss together with vitamin D, especially for those over 60, and a multispecies probiotic from a good health store.  I am normally in clinic on Fridays but during the current lock-down am available for face-to-face online consultations if you would like to get in touch.  For further information, please see my page on this site or

I have concentrated on nutrition in this blog but the importance of stress reduction, sleep and movement cannot be underestimated for supporting immunity. I will leave it to esteemed colleagues at this excellent Centre to expand upon these topics and share their tips and expertise in these areas.

All good wishes to all our lovely clients and their families.


Wendy Smith BSc (Hons), mBANT, CNHC

Registered Nutritional Therapist

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