There’s always one person in the office who’s constantly fighting off a cold. Whether it’s mid-winter or mid-summer, they’ve got the Vicks out and a tissue jammed up their sleeve. And then there are the lucky ones: the colleagues who never take a sick day. On the face of it, you’d think the former would have a weaker immune system while the latter enjoy better immune health. But is that really the case? And if so, how might we improve our immune health to avoid the winter lurgies that are so prevalent at this time of year?

To find out, three plucky members of the Stylist team have been testing their immunity with an at-home finger prick test. Here’s what they discovered.

What is immune health and why does it matter?

Our immune system is “made up of cells, tissues and organs that all work together to help keep our bodies healthy. It’s one of the body’s defences against illness and infection and it works to destroy any unfamiliar cells or germs it encounters such as viruses and bacteria”, Claire Nevinson, superintendent pharmacist for Boots, previously told Strong Women.

Different lifestyle habits and behaviours can influence your immune health. Dr Hana Patel, an NHS GP, explains that prioritising ultra-processed foods over whole foods (eg pre-made snacks instead of rice, oats, fruits and veg) may weaken your immune system. “When you eat these types of foods every day, you don’t leave as much room for foods that are more nutritious, such as fruits, vegetables and fibre-rich grains,” she tells Strong Women. “Eating less of these essential nutrients can decrease the chances that your immune system will defend against illness or recover quickly from it.”

Dr Patel adds that stress and poor sleep can also weaken our immunity as we produce a protein called cytokines in our sleep, which targets infection and inflammation, as well as the production of white blood cells. Maintaining adequate levels of white blood cells is vital in supporting the body’s immune response to infections.

Another factor to consider – especially around the festive season – is alcohol consumption, which directly inhibits immune function, according to Professor David Nutt, co-founder of Sentia. “Alcohol damages tissues in the heart, liver and gut, and the immune suppression increases the impact of infections – from both viruses and bacteria,” he tells us.

Professor Nutt explains that alcohol, beyond a certain dose, acts like a poison – and hangovers are an immune response. “Hangovers promote an inflammatory response as part of the immune system’s response. That can be very destructive to our bodies, weakening your immunity and making you more ill.”

So if you’ve ever wondered why you’ve become sick a few days after a particularly big night out, that might be why.

What is immune health testing (and what do tests look for)?

It can be tricky to try to get to know your body’s immunity, which is why immune health testing kits exist. The Stylist team each took a Forth Immune Health Blood Test, which checks for the key markers involved in our immune function, including vitamin D, white blood cell count and ferritin. The test is simple: just press the spring-loaded lancet into your finger to collect the blood sample. Pop in the post and an NHS lab will analyse your results. You then receive a comprehensive report of your results, which includes personalised comments from GPs.

“The markers we check can have an impact on how well your immune system works,” explain Dr Thom Philips and Dr Alexis Manning from Forth. “Knowing what may be affecting your immunity can help you make changes to your lifestyle and diet, such as adding foods rich in B12 and iron or adding a vitamin D supplement.”

Dr Philips and Dr Manning explain that each of the eight markers being tested for has an impact on our immunity and they’ve broken down what each means for our immune health:

Active B12: “Vitamin B12 is essential for the production of red blood cells and the maintenance of the nervous system. B12 is involved in the make-up of our DNA, so a low level affects all rapidly reproducing cells, including immune cells.”

Ferritin: “Ferritin stores iron, an important mineral for immune function. Iron is involved in the production and function of immune cells, so maintaining adequate ferritin levels ensures iron is available for cells.”

Haemoglobin: “Haemoglobin carries oxygen to cells, including immune cells, so that our bodies have the energy to function properly.”

Red blood cells (RBC): “Red blood cells transport oxygen to your tissues. Proper oxygen levels are important for immune cell function and tissue repair.”

hs-CRP (C-reactive protein): “C-reactive protein (CRP) is a marker of inflammation or infection. While inflammation is a natural part of the immune response, monitoring CRP levels helps assess immune activity balance and identify potential issues, as chronic or excessive inflammation can be harmful, for example, contributing to cardiovascular disease.”

Uric acid: “Uric acid has antioxidant properties and anti-inflammatory effects.”

Vitamin D (25 OH): “Vitamin D plays a vital role in immune function. It can help regulate the immune response with anti-inflammatory effects, preventing an excessive response. Levels can decrease in winter due to reduced sun exposure, and monitoring allows people to identify if they should consider supplementation.”

White blood cell count (WBC): “There are various types of white blood cells which are constantly circulating in the body to both recognise and destroy any harmful bacteria or viruses. And so, if your WBC is high, it would mean your body is attempting to fight off an infection.”

Immune health tests: the results

With all that in mind, here’s what our test subjects found out about the state of their immune systems:

“Fatigue means I struggle to get through the day”

Sophie Boyden, Stylist’s social media lead

Verdict: ‘normal’ immunity

Immune health

I eat a balanced diet, exercise regularly and take my vitamins, and I usually manage to avoid the major colds going around the office. So, why do I always feel a bit… run down? I’ll usually blame it on being busy at work, but the fatigue often means that I struggle to get through a work day without feeling drained, and end up lying on the sofa for hours in the evenings to ‘recover’.

A blood test earlier this year revealed that my thyroid hormone levels are slightly unbalanced, but I was unsure if there was something else going on.

The test results

My test results came through quickly in the app, and while all of my levels were in the ‘normal’ range, Dr Phillips explained that my active B12, vitamin D and ferritin levels were at the lower end of the scale.

Doctor recommendations

My fatigue now made more sense. Dr Phillips recommends a level of 100ug/L of ferritin for optimal health in young women and recommended seeing my GP to see how to keep my levels topped up, as well as taking supplements and eating more foods rich in vitamin B12 and iron. The test has helped me to feel a little more in control of my health and given me a reason to (finally) book that GP appointment to see what else I can do to feel better.

“I never get sick – is that just a temporary fluke?”

Meena Alexander, Stylist’s features director

Verdict: ‘normal’ immunity

Immune health

I have a strong urge to whisper this, rather than shout it out proudly and risk tempting fate, but here it is: I hardly ever get ill. While I’m sure I cross paths with at least a hundred people with hacking coughs on the train every morning, I don’t wake up the next day feeling that tell-tale tickle.

I was intrigued to take a test that might finally confirm or disprove my theory of having a strong immune system, and maybe even give me pointers on how I can bolster my health further as winter hits.

The test results

When I first opened my results to see that, overall, my immunity was ‘healthy’ with no markers falling outside the range of what is ‘normal’ for a woman of 29, I was relieved if not surprised.

Taking a closer look, I could see that the levels of the inflammation marker (hs-CRP) was much lower in my body than the average woman my age. The results also showed I had a robust white blood cell count.

What I didn’t expect, though, was how close I was to experiencing a dip in my immune health. As flagged by the doctor who analysed my results, my vitamin D levels were about to drop outside of the healthy range, putting me at risk of lower immunity.

The doctor also highlighted that my ferritin was ‘very low’, a good indicator that I’m iron deficient. I’d never thought to test this despite feeling fatigued regularly (who doesn’t?) but it is valuable to know that there’s something I can do about it that will also help me avoid infection.

Doctor recommendations

I was recommended a vitamin D supplement for the winter months when getting your fix from sunlight is harder. The doctor also recommended taking a daily iron supplement, alongside an increased focus on eating iron-rich foods such as red meat, beans, dark leafy greens and dried fruit.

“I’ve not taken a sick day for four years – until a cold finally knocked me out”

Miranda Larbi, Strong Women editor

Verdict: ‘normal’ immunity

Immune health

I like to think of myself as a pretty fit and healthy person – I eat my 30 plants a week (known to support immunity), exercise six to seven times a week and sleep quite well. In my 20s, I used to catch colds regularly – constantly fighting off the office bug, but for the past few years, I seem to have stopped catching every cold. Instead, when I do catch one, it totally wipes me out; rather than the monthly runny nose, I’ll be flattened a couple of times a year. Last month, for the first time in four years, I was so ill (with a cold) that I had to call in sick at work for a couple of days. I didn’t even have Covid symptoms the one time I caught it.

I’ve tried a few health MOT blood tests in the past but I was intrigued to see if this test would tell me something different about my immune health – especially as my immune capacity seems to be changing.

The test results

Looking at my results, my immunity score was considered ‘healthy’ with no markers falling outside the range of what is deemed ‘normal’ for a woman my age. The only marker that was flagged in my test results was for ferritin, which came back as lower than average – something that also came up in the a blood test I took earlier this year.

Doctor recommendations

The doctor recommended more iron-rich foods in my diet, looking at how much I exercise and seeking further advice from my GP.

How to improve your immune health

The Forth test is a great tool for people who haven’t been feeling their optimal selves and don’t really know why or where to begin, and it’s a solid starting point for anyone wanting to know a little more about their immunity.

It’s worth saying that if you are concerned about your immunity, then your first step should be to see your GP. But if you want to get clued up on potential deficiencies first, then doing an at-home test is a great way of getting a window into potential issues.

If you simply want to make sure that you’re looking after your immune system, however, then Dr Patel has a bunch of universal tips that can benefit us all.

Think about your booze consumption

Quitting smoking and drinking less alcohol may help to support your immune system by reducing how often it needs to produce an inflammatory response. You’re also more at risk of infection if you drink to excess or smoke, so changing those behaviours can have a positive impact on your immunity.

Stay active

“Exercise improves cardiovascular health, lowers blood pressure and protects against a variety of diseases. As such, it can help to support your immune system and keep it healthy.”

Address any nutrient deficiencies

Dr Patel also says that nutrient deficiencies (for example, zinc, iron and folic acid) can have a negative effect on our immune health, so as well as taking vitamin D during the winter months, it’s worth getting your levels of other nutrients tested. If in doubt, a daily multivitamin can offer support – as can prioritising eating a range of plants. Try to eat as many different colours as possible, as each colour contains different antioxidants and plant chemicals. Given that up to 80% of our immune system is located in the gut, it makes sense that what you feed your microbiome has a massive impact on how sniffly you get.

Ever wondered about the state of your immunity? Team Stylist had theirs tested – and this is what we learned