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Eating to support our immune system

A complicated system

  • The immune system is the second most complicated system in the body (after your brain)

  • It consists of hundreds of different cell types

  • Is controlled by around 8000 genes which interact in a network of ‘near-infinite’ complexity

  • There are two basic systems within the immune system; innate and adaptive;

  • Innate immunity is our first line of defence – the early responders to a problem or invasion

  • Adaptive immunity is slower, more targeted approach with weapons such as T Cells – within the adaptive side we have ‘immune memory’ (memory B cells) which recognise a pathogen and prevent you from getting certain diseases twice!

Like many areas of our amazing body, nutrition and lifestyle can impact on how well things work for us!

Eating to support our immune system

I think of food as nourishment and fuel, i.e. what can it do for us? When we consider eating for immunity that link is no different, how can food make us stronger and indeed, make us feel better (or worse). So, do we just need to eat an extra orange a day for vitamin C or as the old saying goes “An apple a day keeps the Doctor away”. Well, there’s a bit more to it than that but in theory, support your immune function to perform at its’ best and it will do its’ best to protect you from illness. We are all familiar with Vitamin C (Ascorbic Acid) it's classified as an antioxidant, it supports the immune function, helps wounds to heal and is involved in healthy skin, bones, blood vessels and cartilage.

We cannot store vitamin C so a daily supply is needed and the RDA is 40mg. this is best from food sources not supplements. Vitamin C is an important antioxidant as it hunts out free radical activity rather than waiting to encounter it. Now what is an antioxidant?


An anti-oxidant is a molecule which inhibits the oxidisation of other molecules. Oxidation reactions can produce free radicals. Free radicals can start chain reactions. When the chain reaction occurs in a cell, it can cause mutations or damage to the cell. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions.

The body produces its own supply of antioxidants which neutralise the harmful effects of free radicals, one of the most powerful of these is Glutathione, this is produced in the body, it is made from three amino acids (glycine, glutamate and cysteine). Glutathione contains sulphur which makes it excellent at being anti-inflammatory and protective to the body.

These foods help your body to make more glutathione;

· Broccoli

· Brussels sprouts

· Cabbage

· Cauliflower

· Cinnamon

· Tomatoes

· Spinach

· Peaches

What is a Free Radical?

Now what is a free radical? The free radical is unstable and highly reactive because it is an unpaired electron, it wants to pinch an electron from a nearby cell, the problems occur if the free radical pinches an electron from a healthy cell. An antioxidant has spare electrons it can donate to the free radical therefore stabilising it.

This rather simplistic image represents the electron donation

Free radicals are unstable and highly reactive. They are also part of normal bodily functions but can be exacerbated by external influences such as diet, stress, pollutants, exercise, alcohol etc. All of which increase our free radical activity.

I won’t get too science’y but Free radical activity is known as ROS or reactive oxygen species. If this ROS exceeds antioxidants our cells can become damaged.

Oxidative Stress = build -up of bad food, stress, poor sleep, chemicals, overuse of medication, alcohol.

If there are too many free radicals (Reactive Oxygen Species/ROS) and not enough antioxidants to respond to them oxidative stress can occur. You may not realise you are suffering from oxidative stress but these are some of the symptoms: -

· Fatigue

· Brain fog/confusion/diminished brain function

· Joint pain

· Headaches

· Decreased eye sight

· Wrinkles

· Frequent infections

The more serious consequences of oxidative stress over a longer time period are: -

· Chronic fatigue syndrome

· Adrenal fatigue

· Leaky gut

· Fibromyalgia

· Diabetes

· Anxiety

· Cancer

Now that all sounds a bit scary but there’s a lot you can do to protect yourself starting with ensuring you have a plentiful supply of antioxidants, laughing and relaxing, getting some fresh air and sleeping well. (Another day we may discuss Phytochemicals but this blog is getting long! So, here’s some top food & lifestyle tips!).

Top Immune Boosting Tips

  1. Introduce /top up your intake of Probiotics- these are live bacteria to support the health and diversity of your gut microbiome (live yogurt, kefir, kombucha, kimchi, tempeh)Introduce/top up your sources of Prebiotics- these feed the good bacteria that you have (apple cider vinegar, barley, flaxseeds, apples)

  2. Another form of Prebiotic is resistant starch (RS) found in; bananas, peas, grains & seeds)

  3. Yet another form of Prebiotic is Inulin - found in; onions, leeks and garlic, chicory root, Jerusalem artichoke, asparagus & bananas

  4. Eat colourful foods - each food group has different support functions but to boost immunity opt for naturally purple/blue foods as these are high in anthocyanins which promotes the growth of good bacteria Bifidobacterium and Lactobacillus which promote the growth of good bacteria Bifidobacterium and Lactobacillus

  5. Eat Turmeric - Turmeric contains curcumin, along with being anti-inflammatory and a good anti-oxidant this also inhibits the growth of bad bacteria

  6. Eat the right kind of fats - don't be scared of fats, many fats are referred to as EFA's (Essential Fatty Acids) and they are essential for a reason - include oily fish, eggs, avocado, nuts and seeds in your diet for optimal health along with immune support.

  7. Cacao - not chocolate! Raw cacao contains antioxidants, flavonoids and polyphenols and due to the nitric oxide it is good for your cardiovascular system too!

  8. Exercise - Being sedentary is incredibly dangerous for our health. Moving every day is essential for overall health and immune support - light exercise every day has multiple health benefits but is also linked to supporting your immune system due to temporary increase in the production of macrophages, the cells that attack bacteria

  9. Sleep - sleep is when we do our repair and recovery and poor sleep weakens our immune system. The link between sleep and health is quite complex, but it's crucial!

For further blogs and videos on immunity take a look here: -

Immunological Age blog

Mindset and Immunity Video

Louise Mercieca

Nutritional Therapist

Personal Trainer

Award-winning Author

Food & Health Writer

Presenter on Early Years TV Food

Keynote speaker

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