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Immunity... how do we really 'boost' our immune systems?

Updated: Apr 7, 2021

Immune 'boosting' tips and tricks are, understandably, everywhere at the moment due to the current coronavirus situation.

My recent lockdown read has been an amazing book called 'Immunity, the science of staying well' by Dr Jenna Macciochi. The main take away is that immunity is complex and based on a number of both genetic and lifestyle factors!

A key quote used in this book and within the scientific community generally is:

'Our genes load the gun, but our environment pulls the trigger'.

Some of us are luckier than others with the genes we acquire, however, our environment i.e lifestyle choices are what can ultimately determines which genes are expressed ('switched on/off'). This is the evolving science of epigenetics.

So, let's focus on what is in our control when aiding our immune systems in functioning as optimally as possible.

First a bit of background science on the immune system...

Innate & Adaptive Responses

The Innate immune system is our speedy but non-specific response to anything 'non-self'. This includes cells such as neutrophils, eosinophils, basophils, mast cells and macrophages.

The Adaptive (acquired) immune system is our slower (5-7 days usually) but specific response. It involves T cells and the release of antibodies by B cells due to the memory of previous antigens (viruses/bacteria/fungi/parasites/toxins/pollution).

The immune system is made of many cells and organs, such as:

  • Leukocytes a.k.a. white blood cells (all of the above), which release Cytokines as signalling molecules.

  • Lymph nodes- which bring the Innate immune cells and Adaptive immune cells together at the right time and place.

  • The Thymus gland- located between your lungs

  • Bone marrow- makes our immune cells from stem cells.

  • The Spleen

  • The Skin and Mucous Membranes e.g. nose/mouth, Tonsils

  • The Digestive Tract


The typical symptoms of our immune system reacting are due to inflammation (e.g. increased temperature, swelling, pain etc). Short term (acute) inflammation is normal, but issues arise when this process becomes long lasting (chronic).

Chronic low level inflammation is a mechanism in which the immune system plays a role in other conditions such as metabolic issues including diabetes, obesity, high blood pressure and heart disease, as well as dementia and neurodegenerative diseases, depression, chronic pain, chronic fatigue, fertility issues, aging, repair/healing, cancer and, of course, autoimmune conditions.

In fact there is a new term: 'Inflammaging', which describes how chronic low level inflammation can age us faster. As we age, our adaptive immune systems deteriorates due to our bone marrow stem cells slowing down and our thymus gland shrinking. However, our innate immune system increases, causing more inflammation and sucking up our immune systems time and energy. But the good news is, it's thought that 25% of our aging is due to genes with the other 75% due to lifestyle/environmental factors!

Oxidative Stress

Oxidative Stress is the metabolic process in our body that produces free radicals. Free radicals are unstable, highly reactive molecules that cause tissue damage.

Oxidative stress and free radicals are produced by factors such as: poor diet, stress, lack of exercise, smoking and pollution. The process can end up producing too many old, zombie like, dysfunctional immune cells, which again increases inflammation and leads to a downhill spiral. Ultimately, increased oxidative stress is thought to be the mechanism behind the DNA damage that leads to autoimmune diseases, metabolic diseases, neurodegenerative diseases and some cancers.

You may have heard of Antioxidants with regards to this. Antioxidants oppose free radicals. These substances are found in plant based foods in the form of phytonutrients. Fasting and other lifestyle factors may improve our antioxidant levels.

Oxidative stress is not all bad though. For example, it takes place after exercise and eating too due to temporary inflammation! It is about having the right balance of free radicals and antioxidants so we again don't tip into chronic inflammation.

So what lifestyle factors can we work on to improve our immune system?

1) GUT HEALTH- our 'microbiome':

70% of our immune system is found in the gut, so it's no surprise why keeping our gut healthy is key. Our guts have their own microbiomes, consisting of different genes from many bacteria/fungi/viruses inside our digestive tract. In fact, the microbes within us make up around 2kg of body weight!

So how do we keep our good gut bugs thriving?


  • Fibre in our diets. In particular, having 30 or more different plant foods per week. Organic and raw plant foods are best. Research has shown that having under 10 plant foods per week is damaging to our microbiomes. High fibre consumption, on the other hand, has been linked to a 30% decrease in death from all causes including cardiovascular disease and diabetes. From a musculoskeletal point of view, fibre decreases inflammation associated with arthritis.

  • Resistant starches- such as cooked and then cooled white potatoes, oats, rice and lentils.

  • Probiotics- may be beneficial especially before/during/after antibiotic use. Fermented foods- such as Kefir, Sauerkraut, Kimchi and Kombucha.

  • Vitamins D, A and Zinc.

  • Glutamine- an amino acid found in bone broth.

  • Oral health- our oral health may be a snapshot of our microbiome health!


  • High saturated fats within meals

  • High sugar (fructose in the absence of fibre) within meals.

  • Regular snacking

  • Large meals

  • Alcohol

  • Stress

  • Medications- Antibiotics, Antihistamines, Laxatives, NSAID's (non steroidal anti-inflammatories)/Aspirin, Metformin and Proton Pump Inhibitors used for things like reflux. (I'm not saying to come off these following reading this, it's just to be aware of other factors that may play a role! Always consult with your GP regarding medication reviews).

  • Mouthwashes containing Chlorhexidine.

Interestingly, exercising in high heat and women's menstrual cycles (from ovulation to menstruation) can temporarily affect our gut microbiomes in a negative way too!

'Leaky gut' is a concept being researched more and more. It refers to the leaking of potentially harmful bacteria and molecules into our blood streams through our gut barriers, which may be linked to Autoimmune diseases such as Inflammatory Bowel Disease, Coeliacs, Rheumatoid Arthritis and Type 1 Diabetes, as well as food allergies. Our microbiomes are the gate keepers for this gut lining!

2) NUTRITION- & supplements:

Food can be split into micronutrients and macronutrients.

First, let's look at some of the Micronutrients (vitamins and minerals) that are key in immune function:

  • Vitamin C- research shows that a deficiency in vitamin C can increase the likelihood of getting infections and increasing Vitamin C intake may decrease the severity of symptoms and recovery time if we do get ill.

  • Vitamin D- we get this vitamin mainly from sunshine (when our shadow is shorter than us, in spring/summer months here in the UK) and certain food sources (although it is hard to get enough from our food alone). Ideally we need K2 with Vitamin D to aid absorption (and half of K2 is produced by our microbiomes, as talked about above!).

  • Vitamin A- found in plants as Carotenoids and in animal produce as Retinol. Helps the tissues of the immune system e.g. lungs, mouth, gastrointestinal system and aids vision.

  • Zinc- regular dietary intake is key (seafood, red meat & poultry, dairy, wholegrains, beans, nuts etc) as zinc is not stored in the body (and we are less able to absorb it with age). Short term supplementation may be beneficial in decreasing the severity/duration of infections and improving immune defence.

  • Selenium- an antioxidant. It is quite rare to be deficient in this mineral and in the absence of deficiency the author of this book suggests that more may not actually be better (as it may increase inflammation).

  • Phytonutrients- are beneficial chemical components found in plants, with antioxidant, anti-inflammatory and anti-microbial properties. They can be in the form of Flavonoids (found in onions, berries, kale, tea, dark chocolate and more), Carotenoids (found in orange, red and dark green plants), Resveratrol (found in berries, grapes and red wine), Carnosol (found in rosemary and sage) and more!

Now for the Macronutrients...

  • Carbohydrates- are needed for immune function as immune cells need glucose (the break down product of carbs). However, if excessive, this can lead to raised blood sugar in the long run and chronic inflammation. Good quality carbs are key. Go for vegetables and fruit, beans and wholegrains, as these contain much more fibre so they are broken down slower and cause less blood sugar spikes. The more nutrient dense the better, so try not to go overboard on the white bread/pasta! (To work out what a wholegrain is look for 1g fibre to 10g total carbohydrate).

  • Protein- amino acids are the building blocks of proteins and are needed for immune cell production. Arginine and Glutamine are particularly key amino acids. Aim for 0.8g protein per kg of body weight.

  • Fats- in particular omega-3 rich fats. Healthy fats are necessary for our cell membranes and immune cell function. Too many saturated fats, on the others hand, can increase inflammation.

*** For more information on these macronutrients and general nutrition tips, see my blog post:

Other considerations:

  • Alcohol- can increase recovery time from illnesses and negatively affect bone marrow and the liver (which help the immune system function optimally). The conflict comes when it comes to alcohol in the way of things like red wine, where moderate amounts may be beneficial in terms of the polyphenols within it!

  • Capsaicin- decreases inflammation, thereby helping with pain management.

  • Turmeric/Curcumin- decreases inflammation and protects against oxidative stress.

  • Garlic- antioxidant and antibiotic properties.

  • Chicken soup- contains Carnosine, which enhances the power of immune cells.

  • Elderberry- antiviral, can reduce the duration/symptoms of respiratory infections.

  • Echinacea- E Purpurea may be best in preventing colds.

  • Lemon, ginger and honey- it is honey mainly that is recommended by the NHS for coughs before the use of antibiotics.

  • Fasting/time restricted eating- can cause autophagy, the self recycling of cells, which clears out dead/toxic cells and replaces them with new immune cells. Regular meal times and a longer time window between meals may be beneficial e.g. at least 12 hours between dinner and breakfast.

  • Body weight- deserves a separate mention. A healthy body weight links with a healthier immune system. Too much visceral fat (belly fat) means increased inflammation as immune cells like macrophages are stored in visceral adipose tissue. Too little may mean inadequate immune memory cells. So aim for a healthy BMI.

Overall, the discussion about supplements can be complex and confusing! The main thing is a food first approach when it comes to getting these vitamins and minerals. In terms of research on supplements, so far the most evidence points to benefits in taking:

  1. Vitamin D with K2.

  2. Extra Zinc and Vitamin C - for hard training athletes.

  3. Vitamin B12 - if vegan/vegetarian or over 50 years old.

  4. Magnesium.


The effects of movement and exercise on our body can be seen in both physical and psychological effects, both of which effect our immune system.

Exercise has been shown to:

  • Half our risk of catching colds/flu and getting more severe symptoms (with 30-45 minutes of moderate intensity daily exercise).

  • Increase our natural killer cells ten fold (after one bout of activity).

  • Improve the effectiveness of vaccines (when exercising before administration of it).

  • Improve our gut microbiomes (as mentioned above).

Both aerobic exercise (low to moderate intensity) and anaerobic exercise (high intensity) can benefit the immune system. HIIT has been shown to rejuvenate the mitochondria (power supplies) of our immune cells. Strength based training is also important as muscle helps our immune systems.

Rest & recovery is key as over training can be detrimental on our immune systems.

Our lymphatic system relies on muscle contractions throughout the day to pump lymph fluid around the body. Lymph fluid contains white blood cells which help fight infection. The lymphatic system also helps detoxify pollutants/pesticides, transport vitamins, hormones and fats and return fluid to the blood stream. Alongside daily movement and exercise, massage, foam rolling and deep breathing may also help with lymph flow.

Overall, long term moderate exercise is most beneficial for the immune system.

For more information on further benefits of exercise, see my blog post:


Research now shows links between the immune system/inflammation and mental health issues, through the field of psychoimmunology. It used to be thought that the Autonomic Nervous System and the Immune System functioned independently of each other, but we now know that many of these body systems link together. If your nervous system is in chronic 'fight or flight' mode (in a heightened sympathetic nervous system response), certain neurotransmitters are released, activating immune organ and cell responses, often in negative ways! This works both ways, where by if the immune system is also dysfunctional and there is chronic inflammation, it can influence our autonomic nervous system.

Depression- Inflammatory cytokines have been shown to be very high in depression episodes and those with overactive immune systems have been shown to be less likely to respond to anti-depressants. Some psychologists are therefore now using lifestyle strategies to decrease inflammation as a way of helping treat depression in some patients.

Loneliness- is a major issue currently, with 10-30% of those in the UK estimated to be chronically lonely (and up to 50% in Londoners!). Social isolation can cause our nervous system to be in prolonged 'fight or flight' mode and the effects of loneliness may be as detrimental as smoking 15 cigarettes a day. For more information on this and a helpline number:

Stress- causes nervous system and immune system effects, initially increasing inflammation and immune response but causing a dampening effect on our immune systems if prolonged. This may also increase the likelihood of inappropriate immune system response such as that seen in chronic autoimmune diseases, asthma and allergies. As mentioned above, stress can also affect our gut microbiomes through the Vagus nerve which links the brain and the gut. Interestingly it seems to be our perceived level of stress that correlates with this rather than actual life events.

***For more information on stress, the nervous system and actionable tips to buffer stress' effects, have a look at my other blog:

Overall, our immune system is one key system in our brain-body connection, showing how mental triggers can have physical responses and vice versa.


Research has shown that even one night of poor sleep may dramatically decrease natural killer cells, our immune system defence and cancer fighting cells, by around 70%. Getting under 6 hours sleep a night can make us up to 4 times more likely to catch a cold and vaccines may also be less effective if we are sleep deprived.

Not only that, but a lack of sleep can increase pro-inflammatory signals, exacerbating daily pain. Sleep can also affect our metabolism, increasing our diabetes and obesity risk (by up to 45%), Alzheimer's risk and cancer risk.

The two main things to think about are:

  • Quantity: 7-9 hours is optimal. 8-9 if you're particularly busy, stressed or an athlete!

  • Quality: Being asleep for over 85% of the time you're actually in bed and waking no more than once for over 20 minutes.

*** For tips on how to improve your sleep and for professional help links see my Blog post: or look at

Overall, as you can see, there is no one magic boost for our immune systems but instead a number of interlinked factors that provide us with our individual responses to infections. As always, I like to focus on what we can control through small, simple and gradual lifestyle changes.

For more information:

Have a look at at Southcote Proactive Healthcare for our Recalibrate Lifestyle Coaching courses.

Read the book that's inspired this post 'Immunity, the science of staying well' by Dr Jenna Macciochi. Or listen to her on the Podcast 'Feel Better Live More' #125 by Dr Rangan Chatterjee. - Article on the link between the Autonomic Nervous System and Immune System

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