For millions of Britons, this time of year heralds the start of hay fever season, meaning months of misery as their lives are blighted by constant sneezing, runny noses and itchy, watery eyes.
Whether you become one of those unlucky enough to be affected – and to what extent – has always been thought to be a mix of genetics and the environment, with people living in urban areas suffering worse than people in rural areas, for example.
And while pollen is seen as public enemy number one for many sufferers, it may not be entirely to blame.
Groundbreaking new research now suggests that there’s another element at work: the bugs in your nose.
Thanks to advances in science, many of us are now aware that our gut microbiome – the gut soup made up of trillions of bacteria, viruses and even fungi – plays a hugely important role in our health.
For millions of Britons, this time of year heralds the start of hay fever season, meaning months of misery. File image
This microbial mixture is now considered by scientists to be crucial for supporting the immune system and keeping a slew of conditions at bay, including inflammatory bowel disease, obesity, heart disease, food allergies and dementia.
Having a diverse range of insects and a healthy balance of good and bad bacteria is essential.
Now scientists have found that the mix of bacteria in the tissues lining our nasal passages may be just as important when it comes to hay fever.
Hay fever develops in spring and summer (although some people get it year-round), when pollen from grasses and trees comes into contact with the immune cells that line the mouth, nose, eyes and throat.
In those affected, the body mistakes the pollen particles for an infection and responds by flooding the area with histamine, a chemical released into the bloodstream to try to flush out the invading organism. It is this rush of histamine that causes the symptoms.
Over-the-counter remedies provide relief in about 60 percent of cases. These include antihistamine tablets (such as cetirizine and loratadine), which latch onto histamine receptors in the nose and throat, blocking the effects of the histamine rush.
Corticosteroid nasal sprays such as beclometasone (brand name Beconase) and fluticasone (Flixonase) also help by suppressing the immune system response. If these don’t work, patients may be prescribed Grazax – a tablet made with grass pollen that melts under the tongue, gradually teaching the immune system not to overreact. But the drug is only available from a small number of specialist NHS allergy clinics.
However, could changing the bacterial composition of the nasal cavity be an alternative?
This relatively new area of research gained more attention in January when a paper published in the journal Nature Microbiology revealed that the type of bacterial cocktail you have in your nose can determine whether or not you get hay fever.
Researchers from the US National Institute of Allergy and Infectious Diseases in Maryland and Shanghai Jiao Tong University in China compared the nasal microbiomes of 55 adults with hay fever with those of 105 healthy volunteers.
They found that the recruits with hay fever had a much smaller number of bacteria and 17 times the amount of one particular type of bacteria: Streptococcus salivarius.
One of the first insects to colonize the mouths and noses of all of us from birth, it is believed to play an important role in building the immune system in the early years of life. But in hay fever sufferers, the levels seem excessive – and further testing has shown why. When researchers took cells from the mucosal lining of volunteers’ noses, exposed them to pollen, and then placed them in a dish next to S. salivarius and other nasal bacteria, the S. salivarius immediately attached itself to the cells before rival bacteria.
This was due to proteins on the beetle’s surface that for some reason got into the pollen-carrying cells.
Once the bacteria clung to the cells of the nasal cavity, it went on to stimulate cell production of proteins that promote inflammation, while also stimulating the immune system to activate the histamine release that leads to sneezing, watery eyes and runny nose .
Basically, this particular bacteria seems to boost the immune system’s response to the presence of pollen, making hay fever symptoms much worse.
The researchers now plan to investigate ways to lower levels of the rogue bacteria without simultaneously eradicating healthy nasal bacteria.
And some research already suggests there’s a way to do this – by taking probiotic supplements, just as many people already do for a healthy gut.
One such study in 2022, led by scientists at the National Institute of Integrative Medicine in Melbourne, Australia, recruited 40 severe hay fever sufferers during the hay fever season; half took a daily probiotic powder that they sprinkled on food or dissolved in water, while the others received a placebo powder that mainly contained corn starch. The powder, a commercially available product in Australia, contained a wide variety of probiotics that are also commonly found in over-the-counter supplements available in the UK.
The most important were Lactobacillus reuteri GL104, Lactobacillus plantarum LP128, Lactobacillus rhamnosus MP108 and Bifidobacterium lactis B1-04.
The results, published in May 2022 in the journal Frontiers in Nutrition, showed a significant reduction in symptoms in the probiotic group compared to those taking the placebo.
They also reported better sleep and less daytime fatigue (a common symptom of hay fever), while blood tests showed that the group had more anti-inflammatory cytokines (proteins released by the immune system) compared to pro-inflammatory cytokines.
Dr. Karin Ried, director of research at the National Institute of Integrative Medicine and a scientist involved in the study, said that while consuming the probiotics as a powder acts on the bacterial mix in the gut, it would also affect the nasal area. “Probiotics taken orally act primarily on the gut,” she told Good Health.
‘But metabolites [by-products produced when probiotics are broken down in the gut] go through the bloodstream to other parts of the body and thus indirectly affect the nose as well.’
The key to success, she added, is to take probiotics about three weeks before the onset of hay fever season to give the gut microbiome enough time to properly respond.
The findings are partly consistent with those of a small British study from 2013, in which 60 hay fever sufferers were divided into two groups: for 16 weeks, one group drank a drink containing a probiotic every day, while the others received a placebo.
The study, at the University of East Anglia and published in the journal PLOS One, showed significant reductions in nasal tissue inflammation (a key component of hay fever) in the probiotic group due to bacterial changes.
But the patients reported little significant change in their hay fever symptoms. Nevertheless, the researchers concluded in their report, “This is strong evidence of how the gut microbiome can affect distant cells, such as those lining our nasal passages.”
Some research even suggests that our nasal bacterial profile is established in the first few years of life and determines whether we suffer from hay fever from childhood.
A 2018 study by the National University of Singapore, published in the Journal of Allergy and Clinical Immunology, studied nasal swabs from 122 babies in the first 18 months of life. their nose.
British allergy experts acknowledge that research into the nasal microbiome is shedding new light on how hay fever develops, but warn it’s too early to say whether it will change treatment.
‘It has caught the attention of the allergy community,’ says Professor Adam Fox, pediatric allergy consultant at Guy’s and St Thomas’ Hospital in London.
“But the truth is we still know very little about it. For example, we cannot say with certainty whether the nasal microbiome of people with hay fever is this way because they have hay fever, or whether it is the cause of the hay fever.’
An unusual example of this new interest in nasal bugs is transplanting mucus from the noses of healthy donors into those of patients with chronic rhinosinusitis. This condition, which affects almost one in ten adults in the UK, often stems from severe hay fever: it occurs when the nasal passages become inflamed and clogged, allowing bacteria to grow and causing painful infections in the sinuses.
Treatment often includes antibiotics and sometimes surgery to clear the blocked sinuses.
But researchers at the University of Queensland in Australia are currently conducting a trial with 60 volunteers using nasal mucus transplanted from healthy strangers as an alternative to drugs and surgery. The idea is taken from fecal transplants, used by the NHS to fight C. difficile infections.
Researchers say the trial, which is due to end in 2025, could pave the way for an entirely new approach to treating a condition that affects an estimated ten million Britons.