When Covid-19 dominated media streams worldwide, marketers jumped at the opportunity to fill the airwaves with claims their product will boost immunity. But is this even possible? The ability to boost immunity is a highly attractive prospect not just during pandemics but long-term too. We delve into the science to answer the question: can I improve immune function?
What is the immune system?
The immune system is just that: a system. A mind-bogglingly complex system, in fact. One that even top scientists don’t fully understand yet. A myriad of cells, tissues and organs collaborate mostly seamlessly to protect us from the swathe – roughly 60,000 - of pathogens we encounter on a daily basis.
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Without a PhD in immunology, it’s impossible to do the immune system justice, but the basics are relatively straightforward.
A properly functioning immune system will identify foreign bodies from the self and set about attacking those which are intent on causing harm to our being. A (deeply simplified) version of events follows:
- One type of cells called B lymphocytes identify an antigen (bacteria, virus or toxin)
- They begin to secrete antibodies. Antibodies are proteins that specifically target the identified antigen
- Meanwhile, other cells called T lymphocytes coordinate the response mechanism
- These T cells seek out and destroy invaders
The immune system isn’t a single organ - or even a collection of organs – but rather a network of 'cooperation' between various entities within our body. So, does that mean all of our immune systems are the same?
Our defence against the coronavirus comes down to our immune system
Do we all have the same immune system?
We are each born with an innate level of immunity which is determined before we even take our first breath.
New research shows that babies born via caesarean section, for example, have impaired immunity later in life due to the lack of exposure to maternal bacteria that is acquired through a vaginal birth.
And the strength of our immune system changes as we age.
Children are more susceptible to catching colds because they haven’t developed the antibodies with which to combat common antigens. Take chickenpox: we only get it once because after the first occurrence the body stores the antibody needed to fight off another invasion.
The well-documented lifecycle of the immune system shows that as we age we become less susceptible to infections. Vaccinations plays a significant role and provides a fundamental level of protection.
Even as babies, we all have different levels of immunity
As we progress into later years, the effectiveness of the immune system deteriorates, meaning older populations are more at risk of illness from bacteria and viruses.
So, can you alter your immune system?
In short, yes. You can.
There’s plenty of research, which we delve into below that supports the argument for our ability to alter the effectiveness of the immune system.
The strength of our immune system is closely linked to our overall health and our health is generally defined by the lifestyle choices we make, so it’ll come as no surprise that to achieve optimal health – and thus maximise immunity – we should aim to optimise these four factors to boost immunity:
Manipulate each of these to improve or hinder your immune function.
As you’ll come to discover, sleeping your way through the coronavirus could be your best form of defence
1 Nutrition and the immune system
Research clearly shows nutrition supports immune function, but it’s not quite like marketers would have you believe. Various pills, potions and powders claim to improve immunity but unfortunately a lot are pure garbage.
Some, however, have foundation. Indeed, we promote our Ultimate Daily Greens as a supplement to ‘boost immune function’, because science underpins our use of that phase by demonstrating that the ingredients we use have been shown to do just that: boost immune function.
We know a lot about how macro and micronutrients affect immune function and can see that eating to improve immunity is actually fairly simple.
Although some foods directly impact immunity, the greatest impact nutrition has is through its indirect link with immunity through the gut.
That’s because the food you eat has a direct impact on the gut, and the gut has a direct impact on the immune system.
The gut and the immune system
In whatever form you get them – whole or juiced – consuming a wide range of fruits and vegetables will support a healthy immune system
Shipra Vaishnava, assistant professor of microbiology and immunology at Brown University, explains how the gut microbiome and immune system interact:
“The gut microbiome is an ecosystem made of 100 trillion bacteria that have evolved to live in the special conditions of the intestines, Vaishnava said. The vast majority of these bacteria do not harm their hosts but are helpful instead. A healthy microbiome, just like a healthy forest, has many species co-existing together and can fend off hostile intruders -- such as disease-causing bacteria or invasive species.”
At the heart of a well-functioning immune system lies a delicate chemical balance that helps immune cells identify friend from foe. Gut bacteria are key players in this balance.
Prebiotics and probiotics contribute to a well-oiled and diverse gut microbiome which has far-reaching consequences for overall health. Therefore, it’s clear that whatever we can do to improve gut health, the benefits will knock-on to our immune system.
- Professor Dan Peterson from Johns Hopkins University School of Medicine: “A huge proportion of your immune system resides in your GI tract…certain cells in the gut lining spend their lives excreting massive quantities of antibodies”
- Professor Arne Akbar, president of the British Society for Immunology: “We live in a symbiotic relationship with our gut bacteria.”
- Professor Vaishnava, who we met earlier: “Both our diet and the bacteria in our gut are critically linked in regulating how our immune cells behave”.
Thus, if we’re able to impact the gut through nutritional choices, then we can absolutely affect the strength of our immune system.
Kimchi is a tasty probiotic to boost the guts microbiome
This comprehensive list of foods to boost the immune system shares the best food choices to make, but it’s worth noting, however, that as Dr Caroline Apovian, Director of the Nutrition and Weight Management Centre at Boston Medical Centre put it: “If you’re in contact with coronavirus…it doesn’t matter how many oranges you eat, you’re going to get it.”
2 Exercise and the immune system
Prof. Akbar explains that “white blood cells are quite sedentary. Exercise mobilises them by increasing blood flow, so they can do their surveillance jobs and seek and destroy foreign bodies we don’t want.”
For older populations who are more at risk of coronavirus and other infections, remember that “anything is better than nothing”.
Overtraining and the immune system
For those of you who crank out big training loads week on week, you might want to think about dialling it back.
The definition of overtraining is debated, but it’s generally when a person exceeds their bodies ability to recover from strenuous exercise. Either the volume, intensity or supporting framework (sleep, nutrition etc) isn’t sufficient for recovery.
Keep training moderate, enjoyable and, of course, indoors
In the journal Nutrients, Professor Gunzer and his team from the University of Applied Sciences, Austria, explain how “in general, post-exercise immune function impairment is highest when the exercise is continuous, prolonged (>1.5 h), of moderate to high intensity (50%–77% maximum O2 uptake (VO2max)), and performed without food intake.”
Hard training increases cortisol levels which reduces immunity – known as post exercise immunosuppression (PEIS) – so keep training manageable when you’re at risk of infection.
3 Sleep and the immune system
One of the most evidence-based ways to improve health is to sleep more - aim for 7-9 hours per night.
Matthew Walker, professor of neuroscience and psychology at the University of California (and author of the excellent Why We Sleep) states “after just one night of four to five hours of sleep, there is a 70% reduction in critical anticancer-fighting immune cells called natural killer cells”.
Matthew goes on to say:
“We also know that a lack of sleep impacts your cardiovascular system because it is during deep sleep at night that you receive this most wonderful form of effectively blood pressure medication. Your heart rate drops, your blood pressure goes down.
If you're not getting sufficient sleep, you're not getting that reboot of the cardiovascular system, so your blood pressure rises.”
Sleep is a lifestyle factor which you can use to boost your immune system
To improve the quality of your sleep, Matt’s tips for a better night’s sleep include:
- Maintain regularity – go to sleep and wake at the same time each day
- Keep your room dark – blackout blinds and eye masks help those in urban areas
- Do not look at a screen (especially LED screens) within two hours of sleep
- A cooler bedroom is better for deeper sleep
- Avoid caffeine after midday
4 Stress and the immune system
Keeping stress to a minimum in these uncertain times will be hard for many, but everything you can do to reduce the amount of cortisol – the performance wrecking hormone – in your system, the better.
Stress is difficult to define and stimuli will trigger different responses from one individual to the next. It’s also tricky to measure, which makes studying the impact of stress on the immune system difficult.
But studies do exist showing the relationship between the two.
This research shows how chronic stress – ie, abuse – causes “immune dysregulation that may be persistent and severe.”
Less extreme and more pertinent to our current climate, the paper goes on to say: “Finally, research into the effects of stress on inflammation in clinical populations has demonstrated that stress exposure can increase the likelihood of developing disease, as well as exacerbating pre-existing conditions”.
Wherever you're working through the coronavirus - at home or as one of the incredible professions keeping the country afloat - do what you can to minimise stress
A meta-analysis of 30 years research into the impact of stress on the immune system found “In the 30 years since work in the field of psychoneuroimmunology began, studies have convincingly established that stressful experiences alter features of the immune response as well as confer vulnerability to adverse medical outcomes that are either mediated by or resisted by the immune system.”
Thus, it’s very clear that reducing stress in our lives is crucial for optimal health, even more so in a time when coronavirus is running rampant.
Meditation, mindfulness and good old fashioned laughter all do wonders to suppress cortisol.