Do Probiotics Really Reduce Hayfever Symptoms?

Probiotics are live microorganisms - aka the good guys – which are best known for enhancing digestion. But research shows they also impact the immune system and may help reduce allergic symptoms. If you suffer from seasonal allergies and spend months taking over-the-counter hayfever medication, could a probiotic be the natural remedy that helps manage or reduce your hayfever symptoms?

By Nina Sabat

• Understanding Probiotics – What are probiotics, how do probiotic supplements work, how do probiotics affect your health?
• Understanding Hayfever – What is hayfever, the effects of histamine, are probiotics effective for tackling hayfever symptoms?
• Probiotics and Hayfever – What does the research say, are probiotics useful if you have hayfever?

Understanding Probiotics

What are probiotics?

In the world of digestive health, probiotics are often called ‘the good guys.’ Live microorganisms, including both bacteria and yeast, they have a positive effect on digestive health. Different species of these microorganisms are present throughout the entire length of your digestive tract making up your intestinal microbiome. In an ideal world your microbiome will be in balance - there will be a desirable ratio between the numbers of beneficial bacteria (the commensal species) and those that can cause digestive upset.

How many microbes are we talking about? Many thousands! Recently researchers at MIT were able to identify and culture 7,758 different species from the 6 core divisions of bacteria which are found in the human digestive tract.[1]

How do probiotic supplements work?

So, what’s in a probiotic supplement? It’s obvious that you won’t be taking thousands of different species. Instead, probiotic supplements tend to include select species of microorganisms which have been well researched. Typically, they belong to one of seven genera. It’s helpful to think of each genus as a country. Instead of England, Scotland, France and Italy you’ll find names like Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus or Bacillus.

Sometimes, their names seem quite complicated, for example Bifidobacterium longum longum 35624, or Bifidobacterium lactis (CUL-34). These additional details are used to accurately identify each individual microorganism according to its genus, species, subspecies and strain. It’s the same way you can accurately pinpoint a location because you know the country, city, street and postcode.

The microorganisms in your probiotic aren’t expected to set up colonies of their own. Instead, as they pass through your digestive tract, they have transient beneficial effects. This is how probiotics are understood to positively impact your health.

Probiotics and your health

Various studies have revealed the benefits to taking probiotic supplements.

Probiotics can support digestive health.

• In studies a combination of acidophilus, B. bifidum and B. lactis was found to reduce symptoms of IBS.[2]
• The same mix of strains inhibited pathogenic bacteria which cause diarrhoea and bloating.[3]

Health benefits extend beyond the digestive system.

• acidophilus was found to reduce symptoms associated with UTI infections and vaginosis.[4]
• A different strain, plantarum, was shown to support a healthy cholesterol balance, reducing levels of the more troublesome LDL cholesterol.[5]
• In animal studies, probiotics have boosted short-term memory and increased GABA levels. This has been replicated in smaller trials with humans whose attention span improved and levels of anxiety decreased.[6]

Probiotic supplements also impact immunity.

• Taking probiotics reduces the occurrence of respiratory tract infections - keeping more children in school during term-time.[7]
• There are also studies on the impact of probiotics on allergic reactions and conditions like eczema.[8]

That’s right, probiotics are beneficial in instances where allergic reactions are involved.

This is why people who suffer from seasonal allergies often consider whether probiotics can help them manage or reduce their hayfever symptoms.

Let’s continue with a quick look to see what’s happening with hayfever. This will give you some insight into how probiotics may help you manage your seasonal allergies.

Understanding Hayfever

What is hayfever or seasonal allergies?

Hayfever. Aka allergic rhinitis. Aka seasonal allergies. Aka dreading going out in spring or summer because you spend half the day sneezing your head off or with your eyes itching like mad.

For many people having hayfever makes spring and summer challenging seasons. As different plants release pollens into the air, their oversensitive immune systems react as if these pollens were harmful.

• Birch tree pollen is the most common allergen in spring. Oak tree pollen is also released during spring.

• In summer, grass pollens are the most common allergens.

• In autumn ragweed pollen is the most common allergen but pollen from other weeds can cause symptoms too.

Histamine causes hayfever symptoms

In seasonal allergy, there is a whole pathway which involves immune cell antibodies, the triggering of mast cells, the release of a chemical called histamine, and an increase in markers of inflammation, a group of chemicals called cytokines.

As histamine circulates throughout the body it can stimulate receptors in the nose, throat and eyes. Histamine receptors mediate vascular dilation and permeability, smooth muscle contraction in the airways and sensorineural signalling.

What does this unnecessary activation of your histamine receptors feel like?

• With allergic rhinitis histamine receptors in your nose are activated. Symptoms can include sneezing, an itchy nose, a runny nose, a stuffy nose, or pressure in the nose and cheeks. You might also be prone to headaches, cough more, or feel more tired in general.

• Allergic conjunctivitis means your eyes are more affected. When histamine reaches the receptors in this location, your eyes can feel red, watery, itchy, gritty or sensitive to light.

Over-the-counter antihistamine medications are often used to interrupt this histamine-itch-sneeze cycle. But natural remedies can be effective against many of the common symptoms of hayfever as they can target more than just histamine itself.

Are probiotics effective against hayfever symptoms?

Understanding the pathway and what happens during hayfever gives some insight into where natural remedies can be most effective.  There are a lot of moving parts - pollen, an over responsive immune system, mast cells which release histamine, and inflammatory cytokines.

But this also means there are multiple points to target to achieve hayfever symptom relief including:

• Reducing the overall intake of pollen
• Reprogramming the immune system so fewer antibodies are produced
• Strengthening the mast cells so they are less likely to release histamine
• Interrupting the enzymes which activate the histamine molecule
• Breaking histamine down more effectively so it’s cleared out of your system at a faster rate
• Reducing the levels of cytokines and other inflammatory chemicals

If probiotics impact any of these targets, then they would be expected to help you manage your hayfever symptoms and stop dreading the spring and summer months.

Probiotics and Hayfever

The link between probiotics and allergy and how they actually work isn’t crystal clear to researchers. Nevertheless, there is a growing body of work which supports the idea that probiotics help people who experience hayfever symptoms.

Four studies on probiotics and allergic rhinitis

One study investigated the impact of probiotics in children who had a confirmed birch tree pollen allergy. For 4 months one group took probiotics L. acidophilus NCFM and B. lactis Bl-04, while the control group took a placebo.

When the birch pollen season began researchers noted distinct changes in all of the children’s microbiomes. The numbers of Bifidobacterium, Clostridium and Bacteroides were all generally reduced in their stool samples but the children in the study arm had greater numbers of L. acidophilus NCFM and B. lactis Bl-04 when compared to the placebo-taking children.

More interestingly, their symptoms also improved. By May significantly fewer subjects reported having a runny nose, and in June fewer of the children had a blocked nose. When studied under a microscopic, the tissue lining their noses had fewer inflammatory molecules, eosinophils.[9]

In a different small study, subjects drinking milk cultured with L. paracasei ST11 had fewer markers of nasal congestion than subjects drinking regular milk.[10]

In Japan, Japanese cedar pollen is a common allergen. Subjects taking B. longum BB536 every day for 4 weeks had less eye irritation, more enjoyment of daily life and used less medication in total.[11]

However, in another study where a bespoke combination of probiotics was trialled for two seasons, while the measures of inflammatory markers were reduced in the subjects, they didn’t actually report any relief from their symptoms.[12]

Are probiotics useful for hayfever sufferers?

A lot is still unknown about the ideal strain or combination of probiotic needed, and research gives mixed results. Nevertheless, a review of 22 studies investigating probiotics for improving allergic rhinitis reached a positive conclusion:[13]

“Available data provided significant evidence of beneficial clinical and immunologic effects of probiotics in the treatment of allergic rhinitis”

So, could taking probiotics help you manage or reduce your hayfever symptoms during allergy season? It’s certainly something to try.

Summary

Hayfever or allergic rhinitis is a seasonal allergy which leaves many people dreading the spring and summer months. Reacting to the pollen in the air their days are spent sneezing, itching, coughing, or simply hiding inside. Over-the-counter antihistamines target one aspect of the histamine-itch-sneeze cycle but natural remedies can also bring symptom relief. Probiotics – the good guys in the digestive world – have a significant role in immunity and are effective in managing other conditions like asthma and eczema. Research suggests they make a difference to symptoms of hayfever allergy. If you’re looking for a natural approach to managing hayfever, a probiotic is a good place to start.

Take a look at Revital’s extensive range of probiotics here.

About Nina

Nina Sabat is a registered nutritional therapist and supplement and well-being advisor at Revital. Nina enjoys discussing personalised supplement choices and is available via video calls. Perhaps you’re new to supplements or would like some advice on Revital’s extensive range of products? In fact, if you have hayfever and are interested in exploring probiotics or other natural options it’s very simple to arrange a time to talk… Book a Video Call

References

[1] Poyet et al (2019) A library of human gut bacterial isolates paired with longitudinal multiomics data enables mechanistic microbiome research

[2] Williams et al (2009) Clinical trial: a multistrain probiotic preparation significantly reduces symptoms of irritable bowel syndrome in a double-blind placebo-controlled study

[3] Plummer et al (2004) Clostridium difficile pilot study: effects of probiotic supplementation on the incidence of C. difficile diarrhoea

[4] Homayouni et al (2014) Effects of probiotics on the recurrence of bacterial vaginosis: a review

[5] Fuentes et al (2013) Cholesterol-lowering efficacy of Lactobacillus plantarum CECT 7527, 7528 and 7529 in hypercholesterolaemic adults

[6] Owen et al (2014) A double blind, placebo controlled, randomised pilot trial examining the effects of probiotic administration on mood and cognitive function

[7] Garaiova et al (2015) Probiotics and vitamin C for the prevention of respiratory tract infections in children attending preschool: a randomised controlled pilot study

[8] Kalliomaki et al (2007) Probiotics during the first 7 years of life: A cumulative risk reduction of eczema in a randomized, placebo-controlled trial

[9] Ouwehand et al (2009) Specific probiotics alleviate allergic rhinitis during the birch pollen season

[10] Wassenberg et al (2011) Effect of Lactobacillus paracasei ST11 on a nasal provocation test with grass pollen in allergic rhinitis

[11] Xiao et al (2007) Clinical Efficacy of Probiotic Bifidobacterium longum for the Treatment of Symptoms of Japanese Cedar Pollen Allergy in Subjects Evaluated in an Environmental Exposure Unit

[12] Koyama et al (2010) Development and pilot evaluation of a novel probiotic mixture for the management of seasonal allergic rhinitis

[13] Guvunc et al (2016) Do Probiotics have a role in the Treatment of Allergic Rhinitis? A Comprehensive Systematic Review and Metaanalysis