Ever wondered what exactly the immune system is? What does
it need to operate optimally? And how to improve your immune health
over time? The Tonic Immunity Hub has got you covered.


Ever wondered what exactly the immune system is? What does
it need to operate optimally? And how to improve your immune health
over time? The Tonic Immunity Hub has got you covered.


Introducing the Immune System

It’s the first line of defence. It’s a microscopic army. It’s a thing of beauty. But what exactly is our immune system?

However you choose to look at it, the immune system is one of nature’s marvels. And by understanding how it works, you can take better care of it – so it can take better care of you. We’re here to help. At Tonic, we believe we all have innate natural power inside of us. All we have to do is harness it. Not by relying on drugs or hoping for miracles. But by educating ourselves about immune health and following the best scientific advice.

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Breaking down the mystery of the Immune System

Spin the wheel to find out about the seven different parts of the Immune system.

White blood cells

These are your immune system’s star players – the Ronaldos and Messis, so to speak. They only account for about 1% of your blood, but white blood cells are effectively your immunity cells, keeping a lookout for unwanted microbes like bacteria, viruses, fungi and parasites.


These are protective protein molecules that the immune system produces to attack microbes or the toxins created by them. Antibodies can tell that a particular microbe or toxin is an unwelcome invader due to the presence of foreign, disease-causing substances called antigens on the microbe’s surface or in the chemicals it produces.


As the name suggests, this system effectively complements antibodies’ antibacterial activity. It’s a complex system of more than 30 proteins, which react with each other to bind pathogens and prompt an inflammatory cascade response, helping to vanquish infectious microorganisms.


This web of delicate vessels throughout the body helps to keep bodily fluids in balance, in addition to defending against infections. It consists of lymph nodes that effectively filter harmful substances, using their immune cells (lymphocytes) to attack and destroy the germs that lymph fluid brings in.


The spleen is a fist-sized organ in the upper far left part of the abdomen, next to the stomach. It breaks down and removes old, abnormal or damaged cells, in addition to storing red blood cells, platelets and white blood cells. It also produces antibodies and lymphocytes that your body depends on to combat disease.


The spongy tissue at the centre of your bones doesn’t seem like an obvious part of the immune system, but your bone marrow actually produces all three types of blood cell – red and white blood cells and platelets – that keep us healthy. White blood cells are especially important for fighting foreign invaders and infection.


The thymus is a little-known organ situated just below the breast bone. Despite only being active until puberty – after which it begins to slowly shrink and be replaced by fat – the thymus gland is crucial due to its production of progenitor cells. These mature into T-cells, which are instrumental in the destruction of infected cells, while also assisting the growth of other organs in the immune system.

modern life can take its toll

The top threats to immune health

Say a big thank you to your immune system – it’s working a lot harder than you realise. In fact, it’s protecting you from around 60,000 germs every single day.

Your immune system is also under constant attack from a range of factors that can compromise its effectiveness. Learn to recognise them, and you can do your bit to keep your immune system at its best.



Stress is Public Enemy Number 1 for immune health. It’s a leading cause of imbalance in the system, which can weaken your defences.


Poor diet

Here’s one for the pub quiz: over 70% of immune cells are found in your gut. But don’t eat too much pub food. Plants, fibre, healthy fats, pre- and probiotics are the way forward.


Lack of sunlight

Vitamin D is widely recognised as one of the most important immune-supporting nutrients. Unfortunately, our main source is the sun, which means around ⅓ of the UK is deficient in the winter months.


Lack of sleep

Consistent sleep is also a must. It’s been shown that just one bad night’s sleep can cause the number of your immune system’s ‘natural killer’ cells to fall by as much as 70%.


Lack of exercise

It’s a simple equation: more exercise equals fewer sick days. Studies show that people who exercise for 30-45 minutes a day experience a 40-50% reduction in the number of days they get ill.


What do so-called ‘remedies’ actually do?

It’s so instinctive that we hardly think about it. You get sick, you take paracetamol. But what do those drugs actually do?

Well, there’s one important thing they don’t do, and that’s help you get better. It’s so important to think about what you take, and understand how it works. Conventional remedies are good for treating symptoms, like relieving a fever or runny nose.

But those symptoms are actually your immune system at work. And making them ‘go away’ isn’t helping you to get better. In fact, recent research suggests that taking conventional treatments can actually slow your overall recovery.

In times of need, it’s better to support your immune system, let the symptoms do their work, and recover as quickly as you can. At a minimum, it’s important that we’re all able to make an informed choice about what we take and what it will – or won’t – do.

Meet our
And Minerals

Vitamin C

Vitamin C is an essential micronutrient, supporting the function of the immune system in numerous ways. It also has an antioxidant effect, helping to protect cells from oxidative stress. Now, here’s the tricky part: our bodies don’t produce vitamin C, and they don’t store it for long. That’s what makes it so critical to get a regular supply, whether from fruit and veg or vitamin supplements. This is especially true when you’re ill, because sickness actually increases the body’s demand for vitamin C.

Explore Vitamin C Packed Recipes

Vitamin D

Sunlight is our primary source of vitamin D. That’s handy when the weather’s nice, but outside of spring and summer it’s hard to get even the minimum recommended amount of vitamin D. Recent research has also shown people of colour to be particularly at risk of a vitamin deficiency, as darker skin takes longer to produce vitamin D from sunlight. As a result, supplementation is recommended by many experts and public health authorities, including Public Health England. Vitamin D has a host of benefits that include immune support as well as the maintenance of normal bones, teeth and muscle function.

Explore Vitamin D Packed Recipes


Zinc has a whopping 18 recognised health benefits, covering everything from DNA synthesis to macronutrient metabolism and cognitive function. Needless to say, it’s important to make sure you’re getting enough of it. Lack of zinc in the diet is a worldwide problem that can lead to impaired immune function. Deficiency affects all aspects of the immune system and weakens our defences. According to recent research, short-term use of high-dose zinc supplements can help your immune defences in times of need, and helps tissues return to normal.

Explore Zinc Packed Recipes

We created Tonic to have the highest available doses of vitamins C, D and Zinc.

Why those three? First, because they have the greatest weight of scientific evidence to support them. And second, because they’re also the hardest to get adequately from our diet. Basically, they’re where a well-designed supplement makes perfect sense.

- Sunna van Kampen, Tonic Health founder


*Spoiler Alert* You probably need to up your dose

Myth 1: All I need is 100% of my recommended daily allowance

So why is this a myth? It sounds legit. Well RDA is defined as the amount of vitamin you need to prevent nutritional deficiencies. This isn’t the same as optimal health, which would ensure your body has an abundant amount of vitamins and minerals to function optimally. Saying all you need is your RDA is the equivalent to saying I only need to eat food once a month. True, eating only once a month would ensure you probably don’t starve, but you would be very thin, weak and certainly not functioning optimally.

Myth 2: The amount of vitamin I need is consistent all the time

Think of it another way. The amount of water you drink isn’t consistent. Go to the gym or for a run and you soon find yourself reaching for a bottle of water or some electrolytes to quench your thirst. That’s because exercising puts a strain on your body, you sweat and lose water and minerals which then need to be replenished. From a vitamin perspective it is much the same; vitamin requirements fluctuate depending on the situation we are in. When we are stressed, run down, fighting an infection or lacking sleep, our body requires more vitamins and minerals. Some scientific studies have administered doses of up to 8 grams of vitamin C per day to an individual when experiencing cold and flu to have the maximum impact. That’s an incredible 100x more than your RDA. Tough times call for tougher doses.


*depending on how you feel about cold showers

1. Mind your breathing

Mindfulness isn’t just for hippies anymore. Apart from being one of the hottest trends of recent years, it’s also been shown to help the immune system – a review of randomised controlled trials found evidence that meditation is associated with changes in select biomarkers of immune system activity. (Translation: it’s good for you.) Our quick hack? Close your eyes and try six deep inhalations and exhalations whenever you think of it. You’ll be surprised how good it makes you feel.

2. Take cold showers

Scientific studies have found that taking a cold shower increases the amount of white blood cells, a key part of the immune system that helps fight off unwanted viruses and germs. One randomised controlled trial reported showing a 29% reduction in sickness absence after taking a cold shower for 30 days. So, lucky you, it’s definitely worth trying. Ease yourself in by taking your normal shower, then turning it to cold for the last 30-60 seconds.

3. Stay hydrated

The immune system relies on your bloodstream (which is around 90% water) to transport fluids, nutrients, and communication signals to organs. Without proper hydration, blood volume goes down, and reduced blood volume means that this transportation system doesn’t work as well as it could. So stay hydrated, and don’t be shy about trying flavoured water (no added sugars) to make it exciting enough to drink regularly. Remember: by the time thirst hits, you’re often already dehydrated.

4. Consume your collagen

Edible collagen is big in Los Angeles, but don’t let that put you off. Adding extra collagen to your diet can be a smart move for the immune system as it’s responsible for the strength and elasticity of your skin, which is the first line of immune defence. Many of the individual amino acids found in collagen have also been shown to play a role in the immune system, such as glycine, arginine and BCAAs.

5. Cut the sugar

Studies have found a variety of connections between sugar and suppressed immune function. But there’s one that stands out: it’s been shown to block the absorption of vitamin C. Sugar and vit C have a very similar molecular structure and your body absorbs them in the same way, which means sugar can actually inhibit the uptake of vitamin C. This matters, especially when you consider that our bodies don’t make vitamin C and we can only get it from food. (FYI, this is why Tonic has no added sugar.)

6. Get regular rest

Sleep is essential for good immune health – specifically, consistent sleep. Getting just one night’s sleep of less than 6 hours can reduce the function of your immune system’s natural killer cells by up to 70%. To help your routine, our number 1 tip is to keep screens out of your bedroom. Their blue light has been shown to reduce the body’s natural production of the sleep hormone melatonin. Those tweets will still be there in the morning.

7. Take your vitamins

There are many, many studies that have shown how important certain nutrients are to the immune system. So why does Tonic focus on vitamins C, D and zinc? First, because they have the largest body of scientific evidence behind them, and effectiveness is our top priority. Second, because they’re just not that easy to get otherwise. One large orange has maybe 100 mg of vitamin C – one Tonic has 1,500 mg. We get vitamin D from British, ahem, ‘sunshine’. And you’d have to eat half a kilo of sunflower seeds to get the same amount of zinc you’ll find in a single Tonic.


  • Protect your sleep

  • Find balanced in your diet

  • Find balanced in your diet

  • Remove stress where you can

  • Drink plenty of water

  • High doses of vitamins C, D and zinc (or just take a Tonic…)

  • Spread the word, not germs

Your Little
Book of
Immunity Today

Enter your email address below and you’ll get access to our handy Little book of Immunity. Remember...

It’s what’s on the inside that counts!

Your Little
Book of
Immunity Today

Enter your email address below and you’ll get access to our handy Little book of Immunity. Remember...

It’s what’s on the inside that counts!