Oral Allergy Syndrome topples peanut allergy in the 'league tables'
Nutritionist Micki Rose investigates
I was stunned to read in an online BBC news report recently that allergy to fruit and vegetables is set to top peanut allergy in the UK. Allergy clinics are reporting significant increases in the number of cases of oral allergy syndrome (OAS) they’re seeing. They say there are more severe cases than there were before, and that the condition is starting earlier than it did.
I also note that a person can apparently have both a nut anaphylaxis problem and a nut OAS problem. It makes me wonder, perhaps, how many of those suspected of nut allergy are in fact suffering with OAS? It would be interesting to research.
The most common symptom of OAS is a tingling or itchy feeling in the mouth after eating raw fruit and veg. Symptoms can also include itching, swelling or redness of the mouth, lips, gums, tongue or throat, itchy ears, rhinitis, conjunctivitis and hoarseness.
Symptoms can come on immediately after eating or, for the most sensitive, touching or inhaling usually raw fruit and vegetables, spices, herbs, nuts and seeds. The problem is not seasonal as it can occur all year round, but the body tends to be more reactive during the pollen season and slightly afterwards.
Here’s the technical bit about proteins and antigens, so bear with me. It seems that the foods people may become sensitive to do not necessarily come from the same botanical families; it is more to do with similar proteins and similar receptor sites. There are several proteins involved and research is ongoing, but a couple of well-known ones are profilins, regulatory proteins involved in reproduction, hence the link to pollen, and lipid transfer proteins (LTP) which are found in a huge number of plants and help to defend them against pathogens.
Apple skin contains a different protein, Mal d 3, so some people who peel apples won’t react to them at all. That is unless they happen also to have developed a sensitisation to the Pru p 3 protein in peaches which is very similar to the Mal d 3.
• Get a diagnosis, then avoid the foods you know you react to, and possibly rotate the foods in that same group to avoid developing future issues.
• If you have a reaction, swill a liquid antihistamine around your mouth.
• Most reactions are caused by raw foods whereas cooking them can destroy some of the offending proteins, which is why some people can’t eat a raw apple, but are fine with cooked. Unfortunately, the LTPs mentioned above are heat stable and resistant to stomach acid so tend to cause more problems even when food is cooked.
• Experiment with cooking your offending foods, peel them or choose frozen, dried, canned, pasteurised or otherwise processed versions to see if that helps. One point though, if you react to raw celery, nuts, seeds or spices, it seems that cooking doesn’t help so be extra careful. Similarly, if you react to non-OAS foods such as egg, nut or shrimp, get this checked out further as it may not be OAS. If you’re very sensitive, avoid touching or inhaling the offending food. And remember, sometimes food that’s been stored a long time is more reactive than fresh.
• Since pollen is the key, and we know symptoms are worse during and slightly after the pollen season, if you have serious OAS can you structure your life so you spend most of the season near the sea where there’s less pollen, in a different part of the country, or abroad, perhaps? There’s an excuse for a villa in the sunshine…! The Midlands is said to have less birch pollen and you might be able to limit your exposure in the UK with the knowledge that pollen seasons generally start earlier in the south and later in Scotland. Note also that pollen seasons are thought to be starting earlier now because of climate change.
• Make sure you have sufficient stomach acid. We know that symptoms tend to occur in the body above the stomach because the proteins are broken down in the acid there. Stomach acid often lowers after our forties and when under stress, so get checked out by a nutritionist and top it up if need be.
• Improve your immunity. It’s not inevitable that you will develop other trigger foods, especially if you look after yourself well. Regular quercetin, nature’s antihistamine, may help as will keeping your vitamin, mineral and fatty acid levels nice and balanced. OAS is a mix between a person’s immune response and exposure to an allergen, so improving the first and limiting the second seems like a good idea.
• Since we believe air pollution may also be a factor, it would make equal sense to invest in a HEPA air filter, a vacuum with a pollen filter and live as far away from polluted areas, such as major roads, as possible.
In summary, it seems that OAS is becoming more prevalent because of our increased exposure to air pollution and the natural survival of plants able to cope with that pollution. I also reckon our immune systems could do with a bit of an overhaul. There is a lot we can do to limit our own exposure to air pollution, especially inside our own homes, such as chucking out the air fresheners (my pet hate!), controlling dust mites, better ventilation and limiting pollen exposure with HEPA filters and the like, as discussed above.
Either way, it’s worrying. I always thought fruit and veg were the healthiest foods we could eat, but it seems not for everyone. Perhaps we are just learning to adapt to our new chemical age like the plants – we should perhaps be taking a leaf (pun intended) out of their book by adapting and strengthening our bodies to suit.
Hazel (February– April)
Pellitory (June– September)
Mugwort (July– September)
First published in 2009