The gut microbiome is a billions-strong universe living inside your gut[1]. Made up of clever colonies of bacteria, viruses, fungi, archaea, and eukaryotes[2], the microbiome is strongly linked to intestinal health. And unless you’ve been hiding under a rock you’ll probably know that experts have found connections between our gut and our immune system[3]. You probably also know a bit about the gut-brain axis, a physical and chemical superhighway that links gut health and mental wellbeing[4].
But just when you think you know it all about gut health something else drops into your lap. The latest gut link that has us reeling? Allergies…
Allergies and Gut Health: The Link
More and more of us seem to be developing allergies, with the UK in the top three for allergy prevalence and with the highest incidence of hay fever in the world[5] (go us!). It’s hard to know what’s behind this rise but what we are coming to realise is that there’s a relationship between gut microbiota and allergies.
Food allergies and gut health
From milk to bread to eggs, it makes sense that common food allergies and intolerances that give rise to intestinal reactions might be in some way linked to gut health. Indeed, there’s a strong connection between irritable bowel syndrome (IBS), often driven by intolerances to specific food types, and gut microbiota[6].
Recent human studies show that the wellbeing of your gut may also play a role in specific food-based allergies too. The proof? Experts have found evidence that the gut profile of those with food allergies is distinct when compared to those without issues[7].
Hay fever and the gut microbiome
It’s not just food allergies that the men and women in lab coats are linking to our gut health. The results of scientific studies show that those with allergic rhinitis, as hay fever is known in healthcare circles, will usually have a less diverse gut microbiome (and a less diverse nasal microbiome, but that’s a story for another day)[8].
The theory is–as it so often seems to be when it comes to gut health–that hay fever is connected to inflammation, aka the body’s natural response to irritants. And inflammation is, as we all know by now, controlled by the immune system. Immunity is, in turn, strongly affected by the health and diversity of your microbiome.
Other allergies and your gut
Much of the research around allergies and gut health focus on childhood development and it’s this that has led some researchers to discover differences in gut bacteria that may predict the development of peanut allergies in mid-childhood[9]. These studies show that children developing this potentially life-threatening allergy will display reduced diversity of gut bacteria in their earliest years[10].
Additionally, early exposure to pets is seen to influence the makeup of our microbiota[11]. It’s led many to think that the gut could play a role in animal allergies too. It’s as good an excuse as any to say yes to that kitten!
Allergies and Gut Health: The Science Bit
The studies that show a connection between gut flora and allergies (and other aspects of your health for that matter) are widely available online, meaning that anybody can read them for free. Unfortunately, however, these studies can be sci-speak dense and difficult to follow. So let’s get back to basics…
How is the microbiome linked to your allergies?
The headline news, when it comes to studies, is that there is a definitive link between allergies and gut microbiota. This connection is the very same one that brings together your immunity and your gut health (with human immunity thought to be 70-80% based in the gut[12]). This makes sense since an allergy is, at its very simplest, an overreaction by the body’s immune system to something it mistakenly identifies as harmful.
TLDR: since your microbiome is running the show when it comes to your immune system, it’s also taking charge of your allergic response.
Allergy or intolerance: feeling it in your gut
Many of us will develop an intolerance or sensitivity to certain foods–around 20% of us in fact[13]. But it’s important to remember that an intolerance does not an allergy make. So how do you tell the difference?
Symptoms: an allergy can cause swelling, anaphylaxis and skin issues while an intolerance is usually intestinal, causing diarrhoea, gas and bloating
Speed: allergies will show almost immediately, intolerances may come on several hours after exposure
Severity: intolerances aren’t often life threatening while allergies can be
Amount: an allergy can be triggered by minimal exposure while those with an intolerance can usually manage a tiny bit of the bad thing
TLDR: allergies are immune responses while food intolerances or sensitivities are intestinal reactions.
Allergies, immunity and the gut: which came first?
As gut health experts there’s one question that we struggle to solve over any other: did the gut dysbiosis cause the problem or is gut dysbiosis a symptom of the issue? This chicken or egg scenario is especially difficult to answer when it comes to immunity–we can see the connection but we simply can’t be sure where the problem began.
Research into gut microbiota and its link to allergies has come on leaps and bounds in recent years. More and more researchers are now willing to pinpoint microbial diversity and the prevalence of specific bacterial strains as a contributing cause in the development of food, respiratory and skin allergies[14].
TLDR: your gut could be contributing to your allergies.
Allergies and Gut Health: Is There a Solution?
There’s little doubt that a healthier gut can pave the way to a healthier you. What’s less clear is whether improving our gut health can go some way to reversing allergies.
Can better gut health cure an allergy?
A fix as simple as changing your eating habits is unlikely to completely cure an allergy. Improving your gut microbiome could, however, make a marked change to the severity of symptoms[15].
Keep in mind that allergies such as hay fever and pet allergies are the result of an immune response. The way we deal with allergens such as pollen is chiefly through something known as gut-associated lymphoid tissue (GALT), which is where most of that magic 70-80% of our immune system lies. When the bacteria running around in the gut becomes unbalanced the signals GALT sends to your immune system get garbled. Fix the balance in your gut and those signals, though still not necessarily perfect (remember 20-30% of your immunity is elsewhere) should become a little clearer.
Improving gut health with diet and lifestyle
Your gut microbiome begins to take shape before you’re born, with labour and birth playing a part in lifelong gut health[16]. With this in mind you could be forgiven for thinking that there’s nothing you can do about the bacteria you’re dealt. The news is both good and bad: our microbiome is ever-changing, affected by the everyday choices we make.
Improving gut health for better immune defence begins with eating a varied, balanced diet rich in fibre and plant-based goodness. Experts also recommend regular exercise, dodging nicotine and alcohol, and opting for fermented foods like yoghurt, kefir, miso and sauerkraut.
The best supplements for good gut health
While a well-rounded diet is always the aim we’re not always great at keeping those cravings in check. Some of us can’t stand ferments. Others can’t resist a good glass of wine…or four. A foolproof way for the fussy, willpowerless and human among us? A high-quality one-a-day gut health supplement such as Precision Biotics Daily Immune Support Gut and Immune Health Supplements blend gut-friendly scientifically tested L. CASEI 431® with vitamin C for reliable support for your immune system.
Sources:
[1]https://pmc.ncbi.nlm.nih.gov/articles/PMC4191858/
[2]https://pmc.ncbi.nlm.nih.gov/articles/PMC4191858/
[3]https://pmc.ncbi.nlm.nih.gov/articles/PMC8001875/
[4]https://pmc.ncbi.nlm.nih.gov/articles/PMC6469458/
[5]https://www.allergyuk.org/allergy-awareness-week-2024/rise-of-allergies/
[6]https://pmc.ncbi.nlm.nih.gov/articles/PMC6039952/
[7]https://pmc.ncbi.nlm.nih.gov/articles/PMC6905201/
[8]https://onlinelibrary.wiley.com/doi/full/10.1111/all.13812
[11] https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0254-x
[12]https://pmc.ncbi.nlm.nih.gov/articles/PMC8001875/
[13]https://pmc.ncbi.nlm.nih.gov/articles/PMC2695393/
[14]https://pmc.ncbi.nlm.nih.gov/articles/PMC8083053/#s3
[15]https://www.sciencedirect.com/science/article/pii/S2468202023000359
