Do certain foods give you an itchy mouth? Learn how to solve Oral Allergy Syndrome

Do you or your child experience tingling, itching, or swelling in the mouth during or after eating certain foods? You might believe that you have developed food allergies, but you are baffled as your blood tests do not show any specific food allergy antibodies. However, there could be another explanation for these puzzling reactions to the foods you used to enjoy. This type of non-IgE (non-classic) allergy is known as Oral Allergy Syndrome (OAS) and may be linked to a compromised gut lining.

For some people, OAS can be quite mild and triggered by raw fruits such as kiwi fruit, pineapple and fresh figs which can cause temporary mild itchiness in the mouth. And despite the mouth feeling a little tingly for little while, it is not harmful for the intestines or the rest of the body. Therefore, many people enjoy these foods even if they get a short-term little tingle in the mouth.

Similarly high-histamine foods such as tomatoes, strawberries, avocado and banana can trigger red spots or a rash around the mouth. This can first appear when parents are weaning their baby onto these foods. Much of the time your little one will remain happy in themselves despite the rash around their mouth; but equally these high-histamine foods can make a baby quite irritable and affect their sleep if they are highly sensitive. Read this blog on histamine intolerance if your little one is having significant reactions to these foods.

However, some people get nasty reactions, and to a wide range of raw fruits, raw vegetables, nuts or garlic. This is where the lips swell up, their mouth feels extremely itchy, and they feel really uncomfortable for a few days afterwards. When you get this kind of reaction, you can feel quite fearful and cautious of trying that food again in its raw state.

Read on to find out why Oral Allergy Syndrome develops, the surprising reasons it can occur, and I share an example of how we at NatureDoc helped one of our young clients to manage her OAS symptoms so that she is able to confidently eat with her family again without all those horrid OAS reactions.

What is Oral Allergy Syndrome?

Oral allergy syndrome (OAS), also known as pollen-food allergy syndrome, is an allergic reaction, which is most commonly triggered by eating raw fruits, vegetables or nuts. This reaction is usually immediate, mild, and localised to the mouth and throat.

Symptoms of OAS include:

• An itchy or tingling sensation in the lips, mouth, or throat.
• Swollen lips, tongue, or throat.
• Mild redness or irritation of the skin around the mouth.

OAS often affects people who already have an atopic disposition, such as hay fever and certain other pollen allergies. This is because the immune system mistakes similar proteins in fruits and vegetables for the pollen proteins that trigger an allergic reaction. This is known as cross-reactivity and what triggers the OAS symptoms.

Four common pollen-food cross-reactions

In some cases, you can actually track which pollen allergy leads to your OAS trigger foods. Some people will get OAS reactions to all of these foods in their raw state, but most people will only have cross-reactivity to a few foods in these families.

These OAS reactions typically ONLY occur when consuming these foods raw, as the cooking process alters the trigger proteins so that the body no longer reacts to them. Fully cooked versions of these foods such as apple puree, steamed carrots or fried courgette or dishes containing these ingredients such as fruit pies, stews and soups rarely cause a reaction and are usually safe to eat. Partially or lightly cooked versions however, such as stir-fried green peppers or lightly cooked garlic, may still lead to milder symptoms of OAS.

Practical tips for managing OAS

Thankfully, there are a few simple steps you can take to manage OAS.

• Avoid your trigger foods: take note of, and avoid, any raw fruits, vegetables, or nuts that trigger your OAS symptoms. Opt for cooked or processed versions instead.
• Peel your fruits and veggies: the proteins that cause OAS symptoms are often more concentrated in the skin, so peeling fruit and veg can reduce the risk of a reaction.
• Cook your food: cooking alters the protein structures, making the trigger proteins less likely to lead to a reaction.
• Stay hydrated: drinking plenty of water can help to soothe irritation in the mouth and throat and flush out potential allergens.
• Food supplements: mild reactions can be managed by taking vitamin C and a supplement called quercetin which both have antihistaminic properties. Severe allergic reactions are rare, but they can happen. If you experience difficulty breathing or swallowing when you eat, it is essential to seek immediate medical attention.

Why has OAS suddenly developed?

OAS can develop suddenly and at any age, but it’s more common in adults than it is in children, and it can start shortly after a virus, bacterial or parasite infection. Perimenopausal and menopausal women may also develop more oral allergies and reactions whilst their hormones are fluctuating.

There are a few theories about why OAS can develop from an imbalanced gut ecology perspective. Innate immunity in the gut begins with a single layer of intestinal epithelial cells in the gut lining that come into direct contact with both what we eat and the microbes living in our intestines.

Our work at NatureDoc helps to address these underlying factors and develop better oral tolerance to these food allergens. Over the years, we have found that working on these specific areas of gut health can make great headway toward reducing OAS reactions.

Here is a summary of three areas of gut health that you can work on, which all affect the intestinal epithelial cells of the gut lining:

Low Secretory IgA
The secretory IgA (SIgA) antibody is an immunological gatekeeper. It is found in places where allergens may enter the body, like the mucus membranes of the nasal passage and gut lining. When particles pass through, it should tag food and pollens as friends and infections as foe.

However when SIgA levels are too low, the immune system is weakened, and the body is more vulnerable to infection and more likely to develop food intolerances and reactions. Low SIgA can increase the permeability of the intestinal lining, which can in turn increase the risk of absorbing ingested allergy antigens and in turn the likelihood of developing severe food allergies.

The colostrum found in breast milk in the first few days following birth helps to create healthy SIgA levels. Consuming foods like fruits and vegetables high in polyphenols such as berries, red onions and green tea can help to support healthy SIgA levels, as can beta glucans from mushrooms and oats. Enough vitamin A, D and zinc are key nutrients for maintaining healthy levels of SIgA.

Vitamin A
Vitamin A is found in butter and ghee, two powerhouses also rich in butyrate, which helps to repair the gut and create better tolerance to foods. Vitamin A is also found in cod liver oil, creamy milk and cheese. Most multivitamins contain some Vitamin A.

Vitamin D
Research is emerging that links low vitamin D levels with low immune function, predisposing people with low vitamin D to allergies. It’s thought that this may be because vitamin D helps to maintain healthy levels of SIgA.

Sunshine is the best source of vitamin D, but it can also be obtained through the diet in outdoor reared meat, eggs, and oily fish. In the UK, vitamin D supplements are often recommended in the winter months when sunshine is scarcer.

Zinc
Zinc is an important mineral for the immune system and specifically supports SIgA, maintaining healthy levels of this vital antibody. Zinc is found in seafood, meats, dairy, nuts, and seeds and is often found in food supplements targeting the immune system.

Depleted mucin

Mucin helps to protect the body by forming a mucus layer along the gut lining, which blocks harmful germs and encourages healthy gut bacteria to grow. A gut inflammatory marker found in stool tests called beta-defensin may be raised when mucin levels are compromised.

A healthy mucin layer along the gut lining can protect us from OAS – if we work on rebuilding mucin, we may be able to rebuild oral tolerance to these foods. Here are some ways to build up mucin levels and reduce beta-defensin through diet:

Mucin-loving foods
Building up mucin requires a diverse gut microbiome, which can be achieved by consuming a wide range of fruits, veggies, nuts, seeds, pulses, and wholegrains (even if they need to be cooked due to sensitivities), as well as fermented and cultured foods such as live yoghurt, kefir, sauerkraut, pickled cucumbers and kimchi.

To be even more targeted and improve mucin levels further, consume fucoidans which are the polysaccharides found in brown seaweeds such as kombu, wakame, hijiki, bladderwrack and mozuku. Eating aronia berries or drinking juice made from aronia berries have plenty of research to show they help. Consuming prickly pear, which is the sweet fruit of a cactus, may also support optimal mucin production. However these are rare foods in the UK and are not found in the main supermarkets. This is why you sometimes find them listed in food supplements making these mucin-loving ingredients more accessible. Food supplements targeting mucin production also often contain quercetin and olive leaf extract which are both known to help reduce raised beta-defensin.

Night-time fasting
The abundance of certain gut bacteria which sit on top of the mucin called Akkermansia muciniphila is also important for optimising mucin and the gut epithelium. Akkermansia is also heralded for its importance in metabolic health and for keeping a healthy weight.

This family of beneficial bacteria mainly build up their stores at night and thrive when we are in a fasting state. Being able to make enough of this important gut bacteria Akkermansia is one of the reasons we should not snack late at night and we should wait a little while after waking up to eat in the morning.

If you tend to eat late or you need to eat a very early breakfast then not all is lost, as Akkermansia thrives on onion, garlic, leek, artichoke, yam, agave, banana, Brussel sprouts, okra, cauliflower, broccoli and chicory root.

Gut permeability

When the delicate lining of the gut becomes damaged, a condition called ‘leaky gut’ can occur. This is where the tight junctions between the villi in the small intestines lose their ‘tightness’ and allow toxins, undigested food particles and bacteria to seep into the bloodstream.

Gut permeability creates a high alert ‘chaos’ in the immune system, triggering inflammation and increasing the body’s risk of allergy symptoms. The heightened immune response caused by the compromised gut barrier can lead to OAS, as the body becomes more reactive to potential cross reactive allergens.

How can I repair gut permeability?
Overcoming gut permeability can involve a long process of healing the tight junctions in the small intestine. Here is a blog which shares the steps involved when there is significant leaky gut. Using plenty of bone broths, butter, and ghee (clarified butter) should be seen as first steps to restore the tight junctions.

There are also specialist supplements that contain ingredients such as N-acetyl glucosamine and glutamine that may support the healing of the gut lining, as well as other natural soothing and healing compounds containing slippery elm, marshmallow root, and aloe vera which also help to reduce gut inflammation.

“At last, thanks to the team at NatureDoc we can sit down and eat as a family again…”

When one of our NatureDoc clients brought in their lovely young daughter to us for OAS, she was on twice daily prescribed antihistamines and having oral food reactions at almost every meal.

Her parents noticed that certain meals would cause her lips to swell and itch, so much so that it became all-consuming, and her lips would continue to sting for several days even after the initial swelling had gone down. Sometimes the reaction was so severe that her throat swelled up too, needing the maximum antihistamine dose to calm it down. This had understandably put her off trying a lot of new foods, and she became reluctant to eat a lot of the meals she used to love.

We talked her and her parents through how to identify and recognise her triggers, began a programme to repair of her leaky gut, and we recommended quercetin and other supplements to help stabilise her reactions. Her main triggers turned out to be garlic and soya, which were tough to find reliably as they are often hidden ingredients in bread, sauces and soups.

Being able to avoid these two food triggers while working on the root cause has allowed her to decrease her antihistamine use and rebuild her confidence in trying food.

Her mother said: “At last, thanks to the team at NatureDoc we can sit down and eat as a family again, without fear that her lips or throat will swell up.”

Round up

Many people can manage their OAS symptoms easily with the tips from this blog. However if you are keen to explore stool testing for you or your child’s SIgA, Beta defensin and Akkermansia levels and also test for signs of gut permeability, then book in consultations with the NatureDoc clinical team. With this important information gleaned and a personalised health plan, you may notice a wonderful improvement and less nasty itchy reactions, just like our young NatureDoc client.