As the nights get longer and the days get colder, your immune system has more work to do. Hearing the classic phrase, ‘There’s something going round’ may get you wondering what you can do to fortify your defences and keep the bugs at bay during the cold and flu season.
Could this be where probiotic supplements come in? These supplements support the ‘good’ microbes living in your gut and make it harder for harmful bacteria and viruses to grow there.
A whopping 70–80% of your immune cells exist in your gut, and maintaining good gut health supports their work. Your gut bacteria interact with your immune cells in a relationship known as the ‘gut-immune axis.’
‘Your gut and immune system are partners in maintaining your overall health, especially as you prepare for the autumn and winter months’, explains Dr Jenna Macciochi, an immunologist. ‘Understanding and nurturing their connection is essential.’
In this article, we’ll look at the role probiotics can play in a routine designed to support your immune system, and what this could mean for your brushes with colds and flu this winter.
How do probiotics affect your immune system?
Two ways in which probiotics can affect your immune system are:
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by supporting a balanced gut microbiome
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by interacting directly with immune cells in your gut
Gut microbiome and immunity
‘An imbalance of your gut microbiome – the trillions of bacteria that live naturally in your gut – can hamper your immune system’s ability to function at top capacity’, says Dr Sarah Jarvis. ‘This imbalance in the microbiome is called dysbiosis.’
On the flip side, research suggests that having a balanced gut microbiome can support your immune health. This means having a diverse range of bacteria living in your gut, including plenty of ‘good’ gut bacteria and not too many ‘bad’ ones.
Probiotic supplements can help here by delivering live, friendly bacteria directly to your gut. There, they can produce compounds and enzymes that help the ‘good’ bacteria already in your gut while making it harder for ‘bad’ bacteria to grow.
Probiotics and immune cells
Probiotics can support the immune system in different ways.
Studies have shown that probiotics can interact with T cells and B cells, important types of white blood cells in your immune system.
Meanwhile, probiotics could also influence your immune response by stimulating the production of proteins called cytokines. These act as messengers and help control inflammation – a vital part of your immune system.
What the research says about probiotics, colds and flu
We’ve seen that probiotics can support a healthy gut microbiome and lend a hand to the cells in your immune system, but what about specifically dealing with colds and flu?
One review of studies suggests that taking probiotics could reduce the number of times people get the common cold or flu-like illnesses, as well as reducing the symptoms.
Another review gathered data from 24 studies to assess the impact of probiotics on coughs and colds (upper respiratory tract infections). The researchers had data from almost 7,000 people of all ages to examine.
Promisingly, they found that probiotics could reduce:
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the number of people diagnosed with at least one cold by about 24%
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the number of people diagnosed with at least three colds by about 41%
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the average time a cough and cold lasted by 1.22 days
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the number of people who used antibiotics by 42%
Can taking probiotics help me recover faster?
It’s important to note: the potential benefits of probiotic supplements come from regular use. It takes time for the effects of the ‘good’ bacteria to build up. Most studies in the last review mentioned above ran for 3–6 months.
So, it’s unlikely that starting to take a probiotic after you’ve gotten a cold or the flu will make much difference. By the time the probiotics begin to take effect, your illness will likely have run its course.
So, if you’re interested in trying a probiotic supplement to support your immune system this winter, plan to make it part of a daily routine.
Learn how to tell when your probiotics are working.
Practical ways to support your gut during cold and flu season
Good gut health is something you build up over time, and several strategies can help.
Here are five ways you can start supporting your gut health today:
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Have a gut-friendly diet: A well-balanced diet, with plenty of fibre and limited amounts of ultra-processed food, can help with both your gut and immune health.
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Get enough sleep: Good-quality sleep is linked with a more diverse gut microbiome, so aim to get at least 7 hours each night.
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Exercise regularly: Staying active may have a positive effect on the diversity of bacteria living in your gut.
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Manage stress: Lasting or long-term stress can limit how well your gut works and alter the balance of bacteria in your gut microbiome.
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Keep hydrated: Your gut needs fluids to work properly, and being dehydrated can lead to constipation.
If you can work these strategies into your routine, you’ll be well-placed to deal with any seasonal bugs. You’ll also be developing healthy habits that offer benefits throughout the year.
If you’re wondering what to eat to support your gut and immune system, dietitian Sammie Gill has you covered. Check out her weekly recipe plans for inspiration.
Frequently asked questions
Here are some common questions about probiotics and the immune system:
Do probiotics stop you from getting sick?
Some research suggests that probiotics could reduce your risk of getting certain illnesses and limit how long they last.
But it’s important to remember: probiotics are just one piece of the puzzle. They’ll have the most impact alongside other lifestyle adjustments, like eating a balanced diet and exercising regularly.
Can children take probiotics?
Probiotics are suitable for all ages. The NHS says that for most people, probiotics seem to be safe and ‘shouldn’t cause any unpleasant side effects.’
What if you have a weakened immune system?
If your immune system is weakened, such as during cancer treatment, it’s best to be cautious about taking probiotics.
Always speak with a healthcare professional first. They can assess your risk based on your immune status, health condition and medications.
Summary
During the cold and flu season, it’s helpful to support both your gut microbiome and your immune system. Thanks to the gut-immune axis, giving one a boost usually has positive effects on the other.
Probiotic supplements can promote a healthy balance of microbes in your gut, and some research suggests that they could reduce your risk of certain seasonal illnesses.
Probiotics work best as part of a consistent routine that includes other gut-friendly habits, like exercising regularly, eating a balanced diet and getting enough sleep.
And remember: good gut health isn’t a quick fix – it’s your first line of defence over time.
To learn more about other gut health topics, visit Symprove’s Gut Hub.
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