How to strengthen the immune system

You have an entire defence army inside you, defending your body against viruses and other invaders every single day. Without proper nutrition, our defences weaken, leaving us more vulnerable to illness and slower recovery. But how can you strengthen your immune system?

The importance of a strong immune system

A strong immune system keeps your body functioning and protected against the constant stream of bacteria, viruses, fungi, and other harmful cells that can cause illness. 

But when the immune system isn’t taken care of, the foundations of how it keeps your body healthy can start to deteriorate.

For example:

Your second line of defence: When the body’s general defences can’t destroy an infection, what’s known as the “adaptive immune system” steps in.

The adaptive immune system is the second line of defence and zones in on the exact germ causing the problem. It first learns to recognise what it’s fighting, which takes a little longer than it does with the general defences, but once it responds, it attacks with far greater precision.

If your immune system is weak, this process is directly impacted, meaning you’re more susceptible to illness.

Your immune system’s memory: The adaptive immune system can also remember germs it has fought before, meaning that when the same germ enters the body again, the response is much faster and stronger.

People with weakened immune systems have a harder time learning from infections, meaning they may not form lasting immunity or "immune memory" as effectively.

Your wider well-being: A balanced immune system keeps inflammation in check, which supports stable energy and emotional steadiness. When the immune system weakens, inflammation can affect behaviour and mood.

So, how can we keep this strong line of defence happy and healthy? This is where foods, and more importantly, key nutrients, enter the picture. 

Best foods to support your immune system

The nutrients found in food are what keep the immune system steady and strong, but with so many food choices available, it’s easy to feel unsure about what really matters. 

While plenty of foods are nutrient-dense, the real power comes from a healthy balance. For example, eating only fruit might seem healthy, but doing so leaves gaps in other vital nutrients that come from sources like protein or healthy fats. 

A strong immune system thrives on variety, not restriction, and below is a great mix of different foods that are rich in key nutrients for your immune system:

• Salmon: This powerhouse is packed with omega-3 fatty acids, vitamin D, selenium, and protein, all of which help reduce inflammation and support immune cell communication.
• Spinach: Contains vitamin C, vitamin A, magnesium, and folate, supporting cell repair and strengthening the body’s natural defences.
• Citrus fruits: Provide essential nutrients like vitamin C and fibre, which protect cells, regulate fluid balance, and keep inflammation under control.
• Eggs: Eggs offer vitamin D and zinc that help immune cells develop.
• Yoghurt: Yoghurt contains probiotics and calcium, which help balance gut bacteria and improve immune response from within.
• Garlic: Rich in allicin, sulphur compounds, manganese, and vitamin B6 – all linked with improved immune function.
• Pumpkin seeds: These contain zinc, iron, vitamin E, and antioxidants, all vital for healthy immune signalling.

What foods are high in antioxidants?

We’ve all heard of antioxidants; they’re usually the main selling point of most smoothies or “healthy” snacks on the market. But what do antioxidants actually do? Well, every day, your body naturally produces unstable molecules called ‘free radicals.’ These are byproducts of factors like digesting food or polluted air, and because these molecules are missing an electron, they try to “steal” one from other molecules in your cells. 

This process, known as ‘oxidative stress,’ can damage all bodily functions, weakening your immune response. This is why foods high in antioxidants are so important: they neutralise unstable molecules before they can cause harm and help keep your cells strong and healthy, supporting an optimal immune system. 

You’ll find antioxidants in foods such as: 

• berries
• nuts
• seeds
• fish
• eggs
• green tea
• dark chocolate
• colourful fruits and vegetables

What foods fight infection?

Some foods provide your immune system with natural fuel that helps it identify and destroy harmful bacteria and viruses more effectively. They also help keep inflammation balanced, which is key to proper healing and avoiding prolonged fatigue after illness.

Foods that fight infection include:

• Garlic: Contains allicin, a compound that helps white blood cells respond more efficiently to infection.
• Ginger: Calms inflammation and supports healthy immune communication throughout the body.
• Yoghurt: Provides probiotics that nourish gut bacteria, an important part of immune strength.
• Leafy greens: Offer vitamin A, iron, and antioxidants that help repair tissues and maintain strong barriers against pathogens.
• Turmeric: Its active compound, curcumin, has antimicrobial and anti-inflammatory effects that support overall resilience.

Eating a variety of these foods helps your immune defences stay alert and ready, reducing the chance of infections taking hold or lingering longer than they should.

What foods are high in zinc?

Zinc plays a central role in immune defence, helping your body create and activate immune cells that fight infection. It also supports the production of enzymes that repair tissue and keep inflammation balanced. When zinc levels drop, immune responses become weaker, leaving the body more vulnerable to bacteria and viruses. This trace mineral isn’t stored in large amounts, which means it needs to come regularly from food. 

Foods rich in zinc include: 

• shellfish 
• lean red meat
• poultry 
• pumpkin seeds 
• legumes

Probiotics for immune function

A large part of your immune system lives in the gut, where trillions of bacteria help regulate how your body responds to illness. This close relationship between the digestive system and immune function is often referred to as the gut-immune axis. When these bacteria are in balance, they can support immune cell activity.

Probiotics help maintain that balance, giving your immune system a solid foundation. By supporting a healthier gut microbiome, probiotics can help promote overall immune resilience and digestive well-being. They’re especially valuable after a course of antibiotics or illness, when gut bacteria may have been disrupted.

You’ll find probiotics in foods like:

• yoghurt 
• kefir 
• sauerkraut 
• kimchi 
• miso soup

Prebiotics (food for your gut’s ‘good’ bacteria) can be beneficial too.

As an autoimmunity nutritionist, V J Hamilton, explains, “Recent research shows that the microbiome in your gut plays a role in a well-functioning immune system, as 70% of immune cells are in the digestive system.

Eating foods rich in prebiotics, such as Jerusalem artichoke, garlic, and asparagus, helps feed the good bacteria in your gut. Nourishing your digestive system with bone broth, stewed apples, and fermented foods such as sauerkraut and kefir is also worthwhile.”

Superfoods for immunity

It can feel like there’s a new superfood being announced every day, each one claiming to strengthen the immune system or bring better health. But there’s often merit to these claims. Foods like leafy greens, berries, oily fish, and nuts deliver concentrated nutrients that strengthen your immune system and support energy throughout the day. 

These are easy to turn into top immune-boosting snacks, too. 

For example, why not try:

• Greek yoghurt with blueberries.
• A handful of almonds with a kiwi.
• Oatcakes topped with avocado and chia seeds.

Herbs are another group that are sometimes classed as superfoods, thanks to their concentration of natural compounds that strengthen immune function. Some of the best herbs for immune system support – turmeric, ginger, rosemary, and oregano – can typically be found at most supermarkets.

They’re easy to add to meals and drinks, so why not try:

• Chopped ginger in your morning tea.
• Rosemary or oregano in your bolognese.
• Turmeric in your vegetable stir fry.

Remember, balance is always key, so mixing and matching these superfoods in your main meals is a great way to include them all.

Vitamins for immune defence

We’ve mentioned many different types of vitamins. And of course, most of us will understand that vitamins are good for us, but which specific vitamins are beneficial for the immune system?

Let’s take a look:

• Vitamin C: Found in foods like citrus fruits and peppers, it supports white blood cell production and helps protect immune cells from oxidative stress.
• Vitamin D: Present in oily fish and fortified foods, vitamin D regulates immune responses and helps lower the risk of infections.
• Vitamin A: Found in carrots and spinach, vitamin A helps maintain healthy skin and mucous membranes, which act as barriers against germs.
• Vitamin E: Present in almonds and avocados, it works as an antioxidant, protecting immune cells and helping them function properly.
• Vitamin B6: Found in poultry and chickpeas, vitamin B6 helps the body produce antibodies and supports immune communication.

FAQs 

How do I boost my immune system quickly?

There’s no immediate way to strengthen immunity, but prioritising rest and eating vitamin-rich foods gives your body the support it needs. The immune system improves gradually through consistent, healthy habits rather than sudden changes.

Getting enough quality sleep is one of the most important factors. During sleep, the body produces and regulates immune cells, repairs tissues, and manages inflammation.

Regular exercise can also benefit the immune system by supporting circulation and helping immune cells move efficiently throughout the body. Activities like walking, cycling, swimming, or strength training can contribute to overall resilience.

Which fruit gives the highest immunity?

Citrus fruits contain vitamin C, which encourages immune cell activity and supports healing. Kiwi is another excellent choice because it helps the body maintain natural defences and prevents deficiencies that weaken overall immune response.

How to boost the immune system in children?

Encourage children to eat nutrient-dense foods and get enough sleep each night. These habits allow their immune systems to develop properly, reducing the frequency and severity of common infections during early growth.

Where can I find a nutritionist who understands my needs?

If you’re ready to feel better but unsure where to start, Nutritionist Resource makes it simple. Our platform connects you with qualified nutritionists who tailor support to your health goals, whether that’s improving digestion or managing weight. 

Since 2010, we’ve built a reputation for reliable, evidence-based guidance that cuts through nutrition myths. Every expert listed is carefully approved, so you can trust you’re speaking with a genuine professional. Connect with a qualified nutritionist and take the first step towards feeling confident in what you eat.