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woman in hat and gloves outside in winter blowing her nose. woman in hat and gloves outside in winter blowing her nose.

Can diet improve your immune system?

Expert knowledge on diet, health and immunity.

Jennifer Irvine, founder of The Pure Package, recently explored the topic of diet and immunity with two specialists in health and nutrition. Dr Ursula Levine is General Practitioner at Lanserhof at the Arts Club and was Medical Director at Grayshott Medical Spa. She is a qualified Mayr doctor and a traditional Chinese medicine practitioner. Rita Arora is a qualified pharmacist and a lecturer in nutrition, who specialises in allopathic medicine, complementary therapies and homeopathic medicines.

Their knowledge is vast, valuable and fascinating. We’ve captured their answers to some of the most common questions around health, diet and immunity. You can watch the video of their interview here.

Let’s go back to basics. What exactly is the immune system?

The immune system is the bedrock and guardian of our health. But its intangible and complex nature means it can sometimes be misunderstood. It does not exist in one single part of the body, but as a network of cells (including T cells and B cells), molecules (antibodies and cytokines), tissues and organs (such as bone marrow and skin). When things are functioning as they should, these components all work in tandem to protect us.

“There are many aspects to the immune system,” Rita explains. “It’s all about how your body reacts to invaders, be it environmental, bacterial or viral. We’re all born with some immunity which is called ‘innate’, and then we have acquired, or ‘adaptive’ immunity which develops as we grow. The overall aim of the immune system is to keep us free of disease.”

Ursula likens the immune system to a net. “It has two levels – the innate and adaptive, as Rita described. The adaptive can learn to handle antigens which are harmful, foreign substances which attack our body.” Chemicals, toxins, bacteria and viruses can all trigger an immune response, and part of this response is the creation of antibodies which spring into action and destroy any unwanted visitors.

In addition, Ursula divides health into five key components: physical, emotional, mental, spiritual and epigenetics. To achieve a balanced, healthy lifestyle and maintain a strong immune system, it’s crucial that each of these five areas is nurtured through diet, exercise, rest and lifestyle choices.

How do you know if your immune system is functioning well?

When it comes to the immune system, it can be a bit of a guessing game as to whether yours is in tip-top condition or not. How do you know if something is functioning well when you can’t see it?

“When your immune system works, you won’t feel anything. You won’t feel like your body is under attack,” explains Ursula. “Our immune system learns to recognise and remember antigens so the next time we encounter them, our body can quickly engage in a counter-attack. The stronger our defence is, the less you will realise what’s happening in the background.”

If you’re concerned about your immunity, feel tired a lot or are prone to picking up infections, speak to your GP about having a blood test. Your doctor will be able to check for key markers such as vitamin, D, vitamin B12 and iron levels and give you advice.

What can I do to strengthen my immune system?

So, we know that the immune system is our body’s protector, and it’s only when it’s not working effectively (we get ill) or when it’s over-reactive (autoimmune conditions), that we become aware of it.

Ursula explains the importance of firstly cultivating an understanding of the factors that influence our immunity. “Lifestyle. This is often what we want don’t want to hear because it’s down to us.” She reminds us that people looking for a ‘magic pill’ to bolster immunity, or who want to take a more passive approach to their health will be disappointed. Instead, we have to take personal responsibility for our bodies and adjust diet and lifestyle accordingly.

Learn to manage stress and prioritise sleep

“The fundamentals are don’t smoke, eat a healthy diet, work out on a regular basis, maintain a healthy weight and drink alcohol in moderation. And make sure you get enough sleep!” If you can, she suggests, take an afternoon nap when you’re tired. It’s also important to avoid infection where possible – wash your hands, stay away from people you know to be ill with an infectious disease and practice good hygiene when preparing and eating food.

Rita agrees. “For me, the number one thing that is an issue with my clients – especially during the COVID-19 pandemic – is stress and sleep problems.”

Stress and sleep go hand in hand, and when one is poorly managed, it exacerbates the other. Rita recommends simple, practical solutions to this dual problem.

“I tell my clients to take an Epsom salt bath and learn some simple meditation techniques. Make time for rest and relaxation. If you think of your body as a car, and your foot is always on the accelerator, by taking time out to nourish yourself and slow down…it’s like putting the foot on the brake pedal or giving yourself a service.” She suggests thinking of your body as a machine that needs regular maintenance, care and attention in order to function at its best.

To aid sleep further, Ursula is a fan of earplugs, staying away from blue screen light before bed and ensuring your bedroom is cool. She also suggests deep breathing exercises too because this activates the vagal nerve and helps with relaxation.

Rita offers a simple breathing meditation which can help with relaxation and sleep. “I like to breathe in for four counts, then out for eight because this exercise stimulates our parasympathetic nervous system (which puts us into a relaxing state of ‘rest and digest’). I also tense certain muscles, then relax them. I’m a fan of magnesium because it’s your body’s natural rest vitamin and I find that really helps me sleep well.”


We’re passionate about healthy, delicious food at The Pure Package, so it’s no surprise that Jennifer was especially interested in the relationship between what we eat and our immune system.

“Gut health is really important,” Rita explains. “Digestive issues such as constipation and diarrhoea point towards an imbalance of gut health that needs to be addressed.”

Ursula expands: “We now know that gut health is the basis of the immune system and that the microbiome has a significant influence of our body’s defences. We host trillions of bacteria in the gut which define how healthy we are. We can influence our microbiome favourably with healthy nutrition.”

Both Ursula and Rita list some of the best foods you can eat for your immune system – bone broth, cruciferous vegetables, sauerkraut, spinach, pumpkin, mushrooms and turmeric. We should be aiming for ten different, brightly coloured fruits and vegetables a day.

It’s crucial to avoid inflammatory foods which can prevent our immune system working at its best. Sugar, processed foods, refined carbohydrates, red meat, alcohol and certain oils can all trigger inflammation and make us feel bloated, sluggish and tired. Try to minimise, or even better avoid, where you can.

Ursula recommends cooking from scratch where possible and avoiding fast-food and takeaways. (Busy lives can make meal planning and preparation difficult, which is why The Pure Package offers an array of balanced meals, delivered to your door). In addition to eating a diet which is full of fruit, vegetables, healthy protein and good fats, Ursula points out that, in addition to what we eat, problems can also stem from how we eat…

Gold rules of eating

“There are four deadly sins when it comes to eating,” says Ursula. “Too fast, too much, too often and too late.” To summarise, firstly, we all eat too fast. Chew your food properly because digestion starts in the mouth. Enzymes in our saliva start breaking down food before it enters our digestive tract, so this step is crucial. Chewing for longer has also been linked to weight loss, because not only can it decrease the calorific content of food, but it also decreases our hunger levels.

Secondly, portion control is important. Fill your plate, and that’s it. Don’t go back for seconds.

Thirdly, snacking isn’t ideal because you’re not giving your gut a rest in between meals. Have a maximum of three meals per day and stay away from sugar-free chewing gum because it completely destroys your microbiome – your gut wrongly receives a message that food is on its way, stomach acids intensify and damage the good bacteria that are so important to optimum gut health.

Lastly, don’t eat too late in the day. If you eat just before you go to bed, you can’t digest your food. “In Chinese medicine, each organ has its own ‘chronobiology’ which means there is prime time of day for that organ to function at its best,” Ursula explains. “We say as a rule of thumb, the digestive system works best in the late morning or early lunch time. Conversely, the liver, which detoxes and tidies up after the ‘digestive party’, functions best in the middle of the night when we should be asleep.” If you’re stressed and not sleeping properly, your liver cannot detox effectively and the result is inflammation, bloating and a compromised immune system.

“It takes twenty minutes for the stretch receptors in your stomach to indicate that you’re full after eating,” adds Rita. “That can be an issue when you’re eating too quickly and not chewing for long enough. Studies have shown that eating slowly makes people less inclined to overeat, which again, is great for weight loss.”

How can I ensure I’m getting adequate nutrition if I’m vegan or vegetarian?

“There’s no one size fits all,” says Ursula. “A plant-based diet is very, very good for our health, but it might be that for some people, you’d need to supplement with vitamin B12 because it’s hard to get this with fruit and vegetables alone. However, I have a patient in her seventies who grew up near a slaughterhouse and as a result, never touched meat or dairy. And she has no deficiencies at all! I would recommend you have blood tests first, then adjust your diet as necessary.”

Rita adds, “We need protein to repair our bodies. If you’re a vegan or a vegetarian, as long as you’re getting significant plant-based protein at each meal, then you’re going to remain healthy and strong.” Great sources of plant-based proteins include chia seeds, tofu, oats, quinoa and lentils.

Are there any specific supplements I can take to bolster my immune system?

“Vitamin D is the number one supplement we should all be taking right now to improve our health,” says Rita. We’ve written about its potential significance in the fight against coronavirus, due to its ability to support the immune system. It’s also been linked to improving bone and muscle health and reducing the risk of heart disease.

Nicknamed the ‘sunshine vitamin’, vitamin D is primarily gained through our skin’s exposure to sunlight. But between October and March, when the days are shorter and darker, doctors suggest everyone should take a 1000-4000 IU supplement daily to ensure our vitamin D levels are maintained.

However, if you spend a lot of time indoors during the summer months, or you wear long-sleeved clothing, the NHS says that you should consider taking vitamin D daily, throughout the entire year. It’s hard to overdose on vitamin D but if you’re unsure, speak to your doctor.

Ursula agrees, “Vitamin D is definitely a supplement that all we need to take and make sure you take it with food, preferably good fat like olives, or avocado. I also love magnesium because it helps with our physical and emotional health.” You can take an oral supplement, use Epsom bath salts and even use magnesium sprays directly on the skin.


We could talk all day, every day to doctors and nutritionists about the seemingly magical effect good food can have on our health. But sometimes the science can be overwhelming. So, we’ve compiled our top three takeaways from this article which will help you to improve your immune system:

1. Prioritise stress management and work on improving your quality of sleep
2. Eat a wide range of fruit and vegetables and take a daily vitamin D supplement
3. Stay away from inflammatory foods such as processed sugar, refined carbohydrates and excessive alcohol.

At The Pure Package, we know how important a healthy, nutritious diet is for maintaining a healthy immune system. Cooking from scratch, with fresh and seasonal produce is always going to be the best thing for your body, but with busy lives, this can sometimes feel like an impossible task. That’s why we work with experts to lovingly create a range of healthy, nutritionally balanced meals, delivered straight to your door.