Probiotics for Winter Immunity

Kerry Beeson BSc (Nut. Med.) Nutritional Therapist

The immune system: what actually is it?

Put simply: your immune system is made up of several different areas in your body, working together to support you against threats including: physical injuries, toxins, pathogens and even stress!

But… did you know 70% of your entire immune system is based in your gut?

This means if you want to improve your immunity, then supporting your gut health should be a priority in your health regime. Let me introduce you to a totally new way to tackle cold and flu season, starting from the inside out…

How could probiotics and good bacteria support my immune system?

woman on bench
Ticking off all the ways to keep your gut in good shape can be tough. Probiotics are a quick win!

Good health starts in the gut

We’ve learned then, that 70% of our immune system resides in the gut, but let’s jump into this fascinating internal world of the gut and find out what this really means.

Inside everybody’s gut, there’s a multitude of tiny micro-organisms, collectively known as the microbiome. Ideally the microbiome should be filled mostly with good bacteria, commonly known as probiotics. Good gut bacteria have very important jobs: they provide a form of defence against ingested pathogens (‘the bad guys’, such as undesirable bacteria and viruses); they also prevent bad bacteria from sticking to the intestinal wall, and strengthen the delicate intestinal wall. But what you may not know is that they also ‘talk’ to the immune system, helping to enhance immune responses1. Healthcare professionals can head over to the Professionals site to learn more about probiotics and immune health.

You can see then, that if your good gut bacteria aren’t fighting fit then you might be more at risk for picking up infections such as colds and flu. 

Do probiotics help support your immune system?

There are lots of ways you can naturally increase your levels of good bacteria and optimise your gut health, from increasing your fibre intake to getting a good night’s sleep. However, modern life doesn’t always allow us to squeeze all these healthy boosters into our day.

This is where probiotics come in. Designed to keep your gut microbiome healthy in an effective and easy way, probiotics help to create a barrier of good bacteria in the gut. This barrier helps the immune system fight off any nasty bugs we come into contact with in the office, on public transport, or even at home.

Finding the best probiotic to boost my immune system

Probiotics come in lots of different shapes and sizes: yoghurts, fermented drinks like kombucha and most recently, supplements. With 1 in 3 Brits now taking a daily nutritional supplement2, the probiotics industry is growing rapidly. So how can we filter through the noise to find the right supplement to suit you, your gut and your immunity needs?

Perhaps the most important thing to remember is that different probiotic strains do different things, depending on the strains of bacteria in them. In the world of probiotics, revolutionary research is conducted more and more to figure out which types of probiotic strains do what best. The good news is that this long list of research includes – you guessed it – immunity!

A great example is a clinical trial3 conducted in 2018 which found that three different types of good bacteria – Lactobacillus paracasei, Lactobacillus paracasei CASEI 431® and one Lactobacillus fermentum PCC® – were found to be ‘effective for fighting the common cold and influenza-like respiratory infections’. Go gut health!

For daily immunity
Optibac 'For daily immunity' contains Lactobacillus paracasei CASEI 431®
woman sneezing
Can good bacteria help with cold and flu symptoms? The research says yes.

Too late, I’ve already got a cold or the flu - can probiotics still help my immune system?

With luck, you’ve stumbled across this blog before catching a nasty cold or virus bug. However, if you’re in the coughing, sneezing camp already though, don’t lose hope. It’s never too late to start dosing up on good bacteria.

In fact, research shows that people who take probiotics experience colds that are two days shorter in duration, plus their symptoms are 34% less severe than those who don’t supplement with  good bacteria4 So, whether you’re fit and healthy (and plan to stay that way), or you’re in need of some general TLC, good bacteria in the form of probiotics can be a great addition to your daily health regime.

Got the gut health bug? For more:


  1. Montalban-Arques A et al (2015) Selective Manipulation of the Gut Microbiota Improves Immune Status in Vertebrates, Frontiers in Immunology. 6:512
  2. Mintel, (2019). ‘D outshines C to become the UK’s favourite single vitamin supplement’. [Online] Available at: [Accessed 14 Oct. 2019]
  3. Zhang H et al., (2018) “Prospective study of probiotic supplementation results in immune stimulation and improvement of upper respiratory infection rate,” Synthetic and Systems Biology. 3(2): 113-120
  4. Tracey J. Smith, Diane Rigassio-Radler, Robert Denmark, Timothy Haley, Riva Touger-Decker. Effect of Lactobacillus rhamnosus LGG® and Bifidobacterium animalis ssp. lactis BB-12® on health-related quality of life in college students affected by upper respiratory infections. British Journal of Nutrition, 2012; 1 DOI: 10.1017/S0007114512004138