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5 Ways You Might Be Secretly Sabotaging Your Immune System

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Winter always gets us thinking about doing our best to ward off bugs and colds – and this year, immunity is on our minds more than ever.

The immune system is a lot more complex than we often give it credit for – a fascinating network of cells, organs, proteins and tissues with a very important job: to protect the body from outside invaders, like bacteria, viruses and parasites.

It’s working away in the background continuously and many different factors play a role in how it functions, including number of things in our day-to-day lifestyles.

Our immune system is working away to keep us well (iStock/PA)

While avoiding bugs (with good hand-washing, etc) is one of the single most important things for keeping winter bugs at bay, our own habits and lives can also play a part in supporting our immune system – as well as possibly doing it no favours at all.

Here’s five ways you might be sabotaging your immune system…

1. Smoking

It’s common knowledge smoking has a harmful effect on many different areas of the body, and the delicate balance of the immune system is no different.

“Smoking increases inflammation in the body, which can eventually lead to chronic inflammatory disorders, such as heart disease, asthma and arthritis” explains Emily Rollason, senior nutritionist at Holland & Barrett (

“Smoking can also reduce absorption and usage of certain nutrients that are beneficial for immune system support, such as Vitamins B12, C and D; in fact, it’s well known that smokers have higher requirements for these nutrients.”

Rollason says quitting smoking is not only beneficial for your heart and lungs, but  also vital to ensure your body can make a good recovery when it encounters a winter bug. Speak to a healthcare professional if you are looking to quit, as they can talk to you about ways they can support you through the process.

2. Not getting enough sleep

Missing out on good quality sleep is something that affects us in more ways than we realise. “Getting the right amount of sleep is extremely important, particularly when it comes to the adaptive immune response,” says Rollason.

Are you getting enough sleep at night? (iStock/PA)

Rollason explains that the adaptive response is basically when the body stores a ‘memory’ of any previous invading pathogens, in order to help fight it off again in the future. The cells required for these processes are regulated and activated during sleep.

“The body follows a natural internally regulated sleep and wake cycle, known as the circadian rhythm, and there’s evidence to support that many cells in the immune system also follow this rhythm, with certain cells peaking during nocturnal sleep,” Rollinson adds.

She adds that our bodies also burn lots of energy when combatting or recovering from illness, so sleep is really important in helping to fight off any bugs you encounter throughout the day.

3. Not eating a healthy balanced diet

Everything we eat and drink has an effect on our body, and while it’s fine to treat yourself every now and then, regularly gorging on junk food does little to help our immune system, advises Dr Joshua Berkowitz, medical director at IV Boost (

Berkowitz says we should be eating nutritious food with lots of fresh seasonal fruit and vegetables.

“Prioritise a balanced diet full of whole foods, with five to seven portions of vegetable and fruit per day,” adds Rollinson, “and factor in a good balance of good protein, quality carbohydrates and some healthy fats from good sources too.”

Berkowitz also says: “I recommend reducing sugar intake, as this increases inflammation in the body, which can slow down the immune system.”

4. Being deficient in vitamin D

Vitamin D, also know as the ‘sunshine vitamin’, is an essential nutrient for healthy immune functioning, yet many of us are unknowingly running low.

“Despite its name, vitamin D acts more like a hormone in the body, rather than a vitamin,” says Isabel Tarrant, also a nutritionist for Holland & Barrett.

Vitamin D helps support your immune system (iStock/PA)

“It works to activate key immune cells, known as ‘T cells’, which play a crucial role in fighting infections. The vitamin also supports immune functioning by regulating anti-microbial compounds and helping clear harmful bacteria from immune cells.”

As most of our vitamin D comes from sunlight, government guidelines suggest people in the UK take a daily supplement during autumn and winter months, when there isn’t enough sun to meet our needs. Try Holland & Barrett Vitamin D3 250 Tablets 10ug (£3.59 for 100 tablets;

5. Poor gut health

The gut is a very important part of the immune system, and there’s increasing evidence to suggest we shouldn’t overlook the power of our gut microbiome.

“We have approximately 100 trillion live bacteria living inside of us, equating to 2kg of our body weight,” says Tarrant. “This friendly bacteria is essential for our health, and is involved in the smooth functioning of lots of different bodily processes, from the digestive and immune systems to your mood, brain health and skin.”

Guts play a key role in immunity (iStock/PA)

Tarrant explains that gut bacteria produce metabolites, such as short chain fatty acids, which play a crucial role in regulating our T-cells, the key peace-keeper cells of our immune system. Gut bacteria also produce compounds which support the healthy functioning of white blood cells, known as macrophages, Tarrant adds, which are key for fighting off infections and harmful germs.

With stress and anxiety at a high at the moment, it’s easy for your gut health to suffer. Poor diet, high sugar and alcohol intake, excessive antibiotic usage, poor sleep and stress can all contribute to an imbalance in gut bacteria and an increase in negative bacteria, known as dysbiosis.

The good news is there’s lots you can do to help improve your gut microbiome too – and variety is key here. “Try eating a more fibrous diet,” advises Tarrant. “Go for colourful plant foods to ensure you are consuming a diverse range of fibres, such as carrots, yellow peppers, berries, aubergine, spinach, red cabbage, beetroot, broccoli, legumes, nuts and seeds.

“Prebiotics are another great way to promote a healthy gut too. These are live friendly bacteria, which can be found in foods such as sauerkraut, live yogurt, kombucha, kefir and tempeh. Alternatively, there are a range of probiotic supplements on the market to promote a healthy gut.”

Consider your sleep and stress levels too. “Emerging evidence shows a powerful bi-directional relationship between the gut and the brain, known as the gut-brain axis, and stress can cause havoc to the balance of positive and negative bacteria in your gut,” says Tarrant.

Try to manage your stress levels by gentle walks in nature, meditation, yoga or talking to a friend. Promoting a healthy gut is all about lifestyle and wellbeing as a whole, which are key to supporting a healthy immune system this winter.