Is it Really Possible to 'Boost' One's Immune System?

by Laura Jennings

 

Stocking up on supplements, drinking apple cider vinegar, the celery juice cleanse and even certain Yoga poses are just a few of the wellness tips that have promised to boost our immune systems in the past year. In the face of the Covid-19 pandemic, it is essential to have a healthy immune system and this has led to an influx of advice claiming that certain nutrition or lifestyle tweaks can significantly improve one’s immune health.

But is it really possible to ‘boost’ our immune system through nutrition and exercise? 

To date there is no scientific evidence linking lifestyle improvements and increased immune function. The immune system is made up of white blood cells that are located throughout the body in the bone marrow, glands and spleen. The body distributes these cells in response to viruses (especially during flu season).  These cells respond to lots of different incoming microbes, so knowing which particular cells to boost is extremely difficult. Advertisers have jumped on the ‘immune boosting’ slogan as a way of boosting profits instead of health. 

Vitamins and minerals are necessary for optimal function but it’s not natural to take extra large doses in supplement form. Vitamins A, D, E and K are fat soluble vitamins, and become stored in the body’s fat tissues and in the liver. This means that high doses can lead to toxicity. In contrast, vitamins C, B6 and B12 are examples of water soluble vitamins that are easily absorbed by the body. The kidneys remove excess water soluble vitamins, meaning that these supplements will be excreted via urine.

If you are eating a well balanced diet you can get all of the vitamins you need from the different food groups. Vitamin D is an exception to this as we synthesis vitamin D in our skin from the sun. In the winter months we are unable to obtain sufficient levels, therefore, the government recommends a daily vitamin D supplement from September to April, and all year round for those who spend the majority of their time indoors such as the elderly, or for those who always cover their skin including certain religious groups. Find more our supplementing vitamin D in our recent article ‘The Importance of Vitamin D.’

There is evidence to suggest that the vitamins we absorb from foods is absorbed more efficiently than those in supplement form. This is because different components within the food work in synergy with each other other. For instance, foods containing vitamin D, such as mushrooms enhance the absorption of calcium in a meal. It is important to remember that supplements usually contain additives, including bulking and anti-caking agents that provide no nutritional benefit.

It is possible for our immune systems to go into overdrive whilst fighting a virus.  White blood cells can spread past the infected microbes to healthy tissues, attacking both red and white blood cells. This is known as a ‘cytokine storm’ and can be triggered by the flu and autoimmune diseases, such as juvenile arthritis. 

The immune system is all about balance NOT boosting! Healthy lifestyle factors play a key role in keeping our immune system in check.

Here are some general overall health tips to give your whole body (not just the immune system) the best chance at defending itself against invading pathogens:

Fruits & Vegetables

Incorporating lots of different fruits and vegetables into the diet ensure we are getting all the different vitamins we need. Vitamin C rich foods, such as oranges have been scientifically proven to lower the risk of respiratory infections (1). Vegetables, such as spinach, cauliflower and broccoli are rich in antioxidants and can help protect against oxidative stress (2).

Aim for 30 different plant foods per week

Fibre has been shown to be critical for a healthy gut. While 30 may sound like a lot, herbs and spices count as part of that number too! (3) The wider the diversity of fibre packed plants the more varied our gut microbes will be. There is evidence that some of our immune cells are formed and reside in the gut. 

Garlic & Turmeric

The active compound allicin, found in garlic, has been shown to have antiviral properties that can fight bacteria, viruses and fungi. Turmeric has been shown to have anti-inflammatory properties and is a great spice to include in recipes if you feel the onset of flu symptoms. 

Reduce Stress

When we are stressed, the number of white blood cells in the body decreases. This means there are fewer white blood cells to fight off infections, making us more prone to viruses and the common cold. Why not try a hot bath, gentle exercise, calling a friend, listening to a podcast (may we suggest Live Well, Be Well!), cooking a delicious healthy meal, reading a book or reducing screen time as a few simple ways of reducing stress levels. 

Exercise: Exercise is a modulator of the immune system. During and after we exercise anti-inflammatory infection fighting cells are released and  the circulation of these cells increases. This means that we are less prone to infection and symptoms are less severe when we do become ill (4).

However, it is important to note that high intensity training puts stress on the body and floods the body with cortisol, which results in an immediate decreased immune system. If you are already experiencing stress, a gentle form of exercise may be a better option than a HIIT workout that will place additional stress on an already stressed body. 

Hydration: Adequate water intake is the most important nutrient we can consume. The maintenance of fluid and electrolyte function is key to our overall health and hydration status might be a predictor of the onset of disease (5).

Sleep: There is a bidirectional relationship between sleep and the immune system, meaning that they are influenced by each other. Sleep deprivation makes a individual susceptible to infections. For optimal function most adults require  7-9 hours of sleep per night although there is some genetic variation within this. There is evidence that sleep runs the “clean cycle”, which clears metabolic debris from the day and is protective against disease (6).

Social Connection:  Social isolation and social threat have been shown to induce inflammation in the body. Whereas spending time with a friend reduced inflammation and is protective against infection.

References

 1.  Chambial et al (2013). Vitamin C in Disease Prevention and Cure: An Overview

 2. Holt et al (2009). Fruit and vegetable consumption and its relation to markers of inflammation and oxidative stress in adolescents 

3.  Tim Spector (2020). Professor of epidemiology, Kings College London

4.  Silveira et al (2020). Physical exercise as a tool to help the immune system against Covid-19: an integrative interview of the current literature

5.  El Sharkawy (2015). Acute and chronic effects of hydration status on health

6.  Walker, M. (2018). Why we Sleep, Harlow, England Penguin Books. 


 About Laura Jennings

After five years working in the corporate world in luxury fashion and technology, Laura trained as a yoga teacher and joined the team at My Method, curating exciting and diverse wellbeing programmes for private clients and corporates.

Laura has a passion for holistic wellbeing and nutrition and has joined the Be Well team to support with content creation, workshop development and more. She is progressing in the world of health and wellness and is continuing her studies, starting a Masters in Nutrition at King's College London in September 2021.


NutritionFrances Balding