Immunity guide: Supporting your immune system

You likely only think about your immune system when colds and flu are doing the rounds, but it works all the time to protect you.

What exactly is the immune system? How does it fight disease and how can you support it? With insight from Leila Weller-Kis, H&B Nutritionist, we’ll take you through it all...

Your immune system is a complex network of cells, organs and processes designed to protect your body from harm.¹ It helps protect us from harmful germs, such as bacteria and viruses, but its role doesn't stop there. It also helps our body respond to infections, deal with damaged cells and control inflammation.

Most people’s immune systems generally work well, but even a healthy immune system can't always prevent us from becoming ill. It’s important to look after your immune health – however, you can’t ‘boost’ it beyond its natural best. Instead, it’s more about keeping it healthy day-to-day.

Our immune system recognises and responds to potential threats – but it doesn’t stop there. “It also helps our body deal with damaged or abnormal cells and plays an important part in inflammation, which is one of the ways our body responds to injury or infection,” says Leila.^2,3 “For example, if you cut your finger, your immune system quickly responds by sending immune cells to the area to help protect against infection and clear away damaged tissue. This can cause redness, warmth or swelling, which are normal signs of inflammation. As the wound heals, the immune response usually settles down.³ However, too much immune activity can sometimes be harmful, contributing to problems such as inflammation, allergies or autoimmune conditions.”⁴

As Leila explains, our immune system has two main types of defence:⁵

• “Innate immunity is our body's first line of defence, responding quickly to a wide range of potential threats like bacteria and viruses”

• “Adaptive immunity takes a more targeted approach. It usually takes longer to respond when we first encounter a new germ, but it can build long-lasting immune memory, helping our body respond faster if we come across the same germ again”

“For example, when we catch a virus like the common cold, our innate immune system responds quickly, while our adaptive immune system develops a more specific response to help fight the infection. Both systems work closely together, rather than separately, to protect us."^6,7

No two people’s immune systems are the same, and even two people with the same habits will likely experience illness and immunity differently. However, certain habits can play a role in looking after your immune health: ^8,9

• eat a balanced diet

• drink plenty of fluids

• minimise your intake of foods high in fat, sugar and salt

• get a good night’s sleep

• exercise regularly

• maintain a healthy weight

• reduce stress where you can

• follow good hygiene practices

• keep your hands and nails clean

• avoid smoking and limit your alcohol intake

• keep up to date with recommended vaccinations

And there are a few things you can do to help stop germs spreading if you do get ill: ⁸

• cough and sneeze into a tissue and away from other people

• don’t reuse tissues

• don’t go into work and avoid public places, if you can

• regularly clean surfaces and door handles around your home

• wash your hands regularly

Certain vitamins and minerals, including vitamins A, C and D and zinc, are important for normal immune function.^10-13 A balanced, varied and colourful diet can help provide many of the nutrients your immune system needs.

In some cases, you may need a supplement to support immune health – for example, the NHS recommends that children aged 6 months to 5 years take vitamins A, C and D (with some exceptions), while everyone should consider taking vitamin D during autumn and winter. Some groups may need it throughout the year."^14,15 Of course, you should take these as directed. However, “taking more of these nutrients through supplements doesn't necessarily mean we'll have better immunity, particularly if we're already getting enough through our diet,” says Leila.¹⁶

“As children, our immune defences are still developing and we build up immune memory as we encounter different germs,” says Leila.¹⁷ That’s one reason why children tend to pick up bugs easily – they haven’t had as much practice fighting them off.

“As we get older, some immune cells become less effective at responding to new infections. For example, our bodies produce fewer new T cells, a type of white blood cell that helps us fight germs we haven't encountered before.¹⁸ Ageing can also be linked with an increase in long-term, low-level inflammation, and our immune system may not respond as strongly to some vaccines. However, this doesn't mean vaccines stop working. They remain an important way to protect older adults against serious infections.”^18,19

“It's also worth remembering that everyone's immune system ages differently. Factors such as our general health, genetics, environment and previous infections can all play a part. So, it's not quite as simple as saying our immunity just gets weaker as we get older.”¹⁸

Nobody can avoid germs and bugs forever. But with the right habits, you have the tools to help support your immune system and overall health. A colourful diet, plenty of sleep and the right hygiene habits are just some of the ways you can look after your immune system – and hopefully it can return the favour.

Want to know more about staying well? Discover our top vitamins for immune health or browse our guide to supporting kids’ immunity...

Disclaimer – This article provides informational advice and is not a substitute for medical care. Working with experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.