How does nutrition affect the immune system?

Immune systems are complex functions within the body that are essential to healthy living. 

While many factors contribute to how well your immune system works, one of the key elements we have control over is nutrition. 

But before we dive into how nutrition affects the immune system, it’s important to understand what the immune system does, how it works and what other factors can impact immunity.

The function of the immune system 

In its simplest form, the immune system is designed to protect the body against things that could make us sick. 

By detecting unwanted substances like bacteria and viruses, the immune system can take action and begin preventing these substances before they can cause harm. 

Types of immunity 

When talking about the immune system, there are two key types of immunity our bodies can call on: innate and adaptive. 

Innate immunity is the immediate protective barriers that defend against pathogens. The primary protective barriers in our bodies include the skin, mucus, stomach acid, enzymes in sweat and tears and immune system cells designed to combat foreign cells.

Adaptive immunity, on the other hand, is a sophisticated system within the body that essentially learns how to fight specific threats. So when a pathogen invades the body, cells and organs that regulate adaptive immunity create antibodies and additional immune cells designed to eliminate it. 

The body then stores away this information so that it can more effectively defend against these substances if and when they’re detected again. 

What impacts a healthy immune response? 

The way your immune system functions is impacted by so many different factors, some that are within your control and some that aren’t. 

Some of the factors outside your control include: 

Age

Many systems within the body become less effective as we age, including the immune system. This is because organs linked to immune systems begin producing fewer immune cells and therefore need to work harder to combat harmful substances.

Getting older has also been linked to deficiencies in micronutrients, essential elements that contribute to a range of physiological functions - including immunity. 

Disease

There are a number of chronic diseases and disorders that cause immune cells to target healthy cells rather than harmful ones. 

Immune suppressing diseases include things like autoimmune disorders (such as rheumatoid arthritis or lupus) and immunodeficiency disorders (like AIDS and leukemia). 

Some of the main factors that you can (and should) aim to control include:

Exposure to toxins

Environmental toxins from exposure to things like smoking, excessive alcohol consumption and air pollution have all been associated with irregular immune cell activity. 

This may be due to increased production of free radicals in the body which can be harmful to healthy cells.

Body weight

Research suggests that excessive body weight and obesity can be linked with chronic inflammation. As chronic inflammation is known to cause tissue damage and have adverse impacts on the immune system, it’s very likely that body weight is a risk factor for the immune system. 

Stress 

Stress hormones such as cortisol have been found to hinder the body’s natural generation of inflammation. While excessive inflammation is harmful to the body, some inflammation is necessary to trigger an immune response. 

This means that keeping stress levels under control is crucial for supporting immunity. 

Lack of sleep

When we sleep, our bodies are working hard to restore and repair. It’s also a time when cytokines are released, aiding communication between cells and encouraging immune cells towards the site of inflammation and infection. 

Therefore, lack of sleep inhibits the release of cytokines and reduces the effectiveness of an immune response. 

Malnutrition

Adequate nutrition is essential to supporting healthy functioning immune cells and efficient immune responses against pathogens. 

Like other functions in the body, the immune system requires adequate energy to operate at optimal levels and nutrition is key to ensuring it can do its job effectively. 

Relationship between nutrition and the immune system

Having a balanced diet packed with all kinds of nutrients is critical to all aspects of health, including the healthy functioning of immune cells.

There are certainly some types of foods that can help to better prepare the body against harmful substances, however no single food can offer complete protection. This is because immune systems are made up of many stages and each requires a wide range of micronutrients to thrive. 

To make sure you’re getting the right nutrition to boost your immune system, aim for a varied diet consisting of vitamins C and D, protein, zinc, selenium, fibre and iron. These have been identified as key players in keeping immune cells healthy. 

On the flip side, simple diets containing high levels of processed foods, refined sugars, red meat and little plant-based ingredients can have a negative impact on immunity. 

These kinds of food patterns can disrupt intestinal microorganisms that are required to manage inflammation and immunity. 

Gut health and immunity

In recent years, extensive research has been carried out on the gut and more specifically, the gut microbiome in relation to its role in supporting immunity.

The gut microbiome is a collection of trillions of microbes that are needed to keep us healthy. With this in mind, it’s no surprise that nutrition and gut health play a major part in immune function as this determines the types of microbes that reside in the gut.

To support the production of beneficial microbes, research suggests that a diet high in fibre, plant-based foods, legumes and grains is a great place to start. This is because specific microbes help to process fibres and turn them into short chain fatty acids that encourage healthy immune cell function. 

Fibre that helps in this way is known as a prebiotic and is important for supporting colonies of good bacteria. Probiotics are also important for gut health as they contain the good bacteria that the gut needs to thrive.

Foods to help immune function

As we now know, pre and probiotics are essential to supporting a healthy gut microbiome and by extension, a healthy immune system. 

Some of our favourite prebiotic foods for supporting gut health include chicory root, Jerusalem artichokes, onions and seaweed, among others. 

In terms of probiotics, we love yoghurts with live cultures, kombucha, kimchi, sauerkraut and organic fermented miso. 

We also recommend trying Populate, our Bone Broth Body Glue™ featuring both pre- and probiotics for enhanced gut and immune health.

The bottom line

There’s no single food that can give us everything we need to maintain a healthy immune system; consuming a really varied and balanced diet is the best plan of attack.
Ensure you’re including a range of fruits and vegetables, grains and legumes in your diet as well as pre- and probiotic fibres. Combining this with a healthy lifestyle void of toxins and stress should give you a better chance of maintaining a high-functioning immune system. 

 

Sources:

The Nutrition Source. 2020. Nutrition And Immunity. [online] Available at: https://www.hsph.harvard.edu/nutritionsource/nutrition-and-immunity [Accessed 8 October 2020].

Childs, C., Calder, P. and Miles, E., 2020. Diet And Immune Function. [online] National Centre for Biotechnology Information. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723551 [Accessed 9 October 2020].