The surprising link between seasonal allergies and food


Why would your seasonal allergies suddenly make you allergic to foods you’ve never had problems with?  If you’re allergic to pollen, why would that cause an allergic reaction to oranges or peaches? And how come these new allergies aren’t showing up on diagnostic tests?

Typically affecting older kids, teens, and young adults—unexpected and unexplained food allergies are showing up increasingly often. And this allergy mystery had the experts puzzled.

A mouthful of symptoms

Food allergy symptoms can be similar to common seasonal allergies.  But diagnostic tests that reliably confirm a seasonal allergy rarely confirmed a food allergy.

But why?

Food allergies are common enough.  And although some come with dire reactions, many of the more typical reactions—itchy, watery eyes, sneezes, hives, rashes, constant runny nose—really disrupt people’s lives.  Especially when the symptoms aren’t seasonal, but persist year-round.

A key insight emerged when experts nailed down what made these new food allergies different than seasonal allergies—the first symptoms people reported were swelling and itchiness of the lips, mouth, tongue, and throat immediately after eating a certain fruit, vegetable, seed, or nut.  That wasn’t the way typical seasonal allergies announce themselves.

Connecting the dots

The new phenomenon earned a name of its own: oral allergy syndrome. And it’s now estimated that more than 60 percent of all food allergies are somehow associated with seasonal allergies. That’s a lot of discomfort for a lot of people.

But how to connect the dots? Enough data came in to show that common seasonal allergies were definitely connected to allergic reactions to certain foods:

Seasonal Allergy Associated Food Allergy
Birch pollen Apple | Almond | Carrot | Celery |Cherry| Hazelnut  |Kiwi |Peach |Pear | Plum
Grass pollen Celery |Melons |Oranges | Peaches | Tomato
Ragweed pollen Banana | Cucumber |Melons | Sunflower | Zucchini

But why?  What connects ragweed and zucchini? Birch pollen and hazelnuts?

It took a long time to put all the pieces together.

It’s cross-reactivity

Our immune system is fearless, diligent, and powerful. It’s on the job 24 hours a day, every day, throwing its best protective and destructive stuff at every unwanted intruder.

But sometimes, it mistakes a harmless presence—a food, for example—for a dangerous one. The result is “friendly fire,” good guys attacking good guys.

But still…why?

Now we know. When a seasonal allergy sufferer eats an associated “trigger” fruit, nut, seed, or vegetable, the immune system sees familiar proteins—very similar to those associated with the underlying seasonal allergies themselves.

So our rapid response immunity team leaps into fight mode, in a process called cross-reactivity.  The outcome of the battle is an allergic reaction.

What’s not yet understood is the seemingly random timing—why the immune system suddenly decides that what we’ve eaten for years is a threat.

Research will eventually find ways to obstruct or eliminate oral allergy syndrome.

Meanwhile, here’s what various experts recommend to keep it at bay.

Keep your fingers off the triggers

Obviously, the surest way to prevent an oral allergic reaction is to avoid your trigger foods.

Fortunately, there are ways to “de-fang” your trigger foods so you can still enjoy them.

Peel first.  A great many reaction-causing proteins reside in a fruit or vegetable’s skin. Just peeling them before eating—wearing gloves—can reduce the likelihood or intensity of a reaction.

Cook.  With some trigger foods, cooking can destroy the proteins that cause oral allergy reactions. If, for example, you love tomatoes, apples, potatoes, pears, or (most) soft fruits, breathe a sigh of relief.

But if nuts, some spices, strawberries, or celery are your trigger food, you’re out of luck.  Nuts and strawberries, bless their sweet hearts, contain heat-resistant allergens.

What about juices? If they’ve been pasteurized, they’ve been cooked—so many fruit and veggie juices are usually okay. But a few caveats:

  • Fruit juice alone, without the whole fruit’s flesh and skin, is little more than liquid sugar that tastes good—and lacks the whole plant’s fibers. Also, by pressing, you may activate enzymes and protein that change the nutritional profile.
  • Many commercial smoothies contain raw, unpasteurized juices or purees that might be among your trigger foods.
  • All sorts of breakfast cereals, trail mixes, energy bars, and the like contain nuts, or were processed in a plant where nuts have also been processed.

So read the ingredients labels before consuming, well, almost everything.

Microwave.  Pop the fruits or veggies in the microwave on a low power setting for about a minute, then chill them immediately.  This may deter or reduce the allergic reaction. It eliminates the main reaction-causing proteins, and works especially well for apples.

Of course, protecting against the underlying seasonal allergy will also make a world of difference.  That means, as always, a healthy diet and lifestyle.  Those in themselves will keep your immune system humming along.

But it certainly doesn’t mean resorting to Big Pharma’s billion-dollar OTC babies. There are safer and more affordable natural remedies that are equally or more effective. Here are some recommendations.

Safe, natural, anti-allergenics

As always, nature provides wonderful solutions.

Quail egg powder sounds like an unlikely allergy-remedy. But five human clinical studies show that it can actually halt allergy symptoms starting in just 15 minutes. And folks who took it daily for three months or more reported their symptoms all but disappeared.

Butterbur is a member of the sunflower family. It’s proven effective against allergies—90 percent of patients improved in clinical trials, making butterbur as effective as Big Pharma’s big earners, Zyrtec® and Allegra®.

Rosmarinic acid, an extract of rosemary, has proven anti-allergenic properties, reducing the histamine production that is part of every reaction.

Quercetin, a compound found in many fruits and vegetables, particularly onions, performs as well as pharmaceutical drugs in clinical trials.

Bromelain, an enzyme from pineapple, has anti-inflammatory abilities that make it another good choice for treating seasonal allergies.

Extracts of stinging nettle have been used for centuries to treat allergies.

Consult with your doctor on the suitability and dosages best for you.

Homeopathy is a healing technique that uses micro-doses of allergens to treat specific symptoms, “training” the immune system to not attack them when they’re present. Remedies are packaged according to symptoms—runny nose, itchy eyes, cough and so on, making it easy to find the one you need.

Clean up inside. The fewer allergens, the better, outside and in. You can’t do much about the ones outside. But you can reduce exposure to pollen and dust mites in your home.  There are mattresses and pillow covers, for example, made to control dust mites.

For a super-cleanup, I recommend a High Efficiency Particulate Air (HEPA) air filtration device.  You’ll be amazed at what you’ve been living with when it’s been running for a while.

Finally, a tip from NASA’s playbook:  green plants, which those super-smart scientists call “living air filters.” Get plants big enough for at least 6-inch containers, and put out one plant for every 100 to 120 square feet of space.  Note: no flowering plants—pollen.

If you experience oral allergy syndrome reactions, or a sudden new food allergy, let your doctor know right away.  As I said, food allergies are rarely truly threatening. But be like your immune system—be safe rather than sorry.

I hope this will help you breathe easier.

Take good care.


Last Updated: April 11, 2020
Originally Published: September 15, 2017