By: David A Fein, MD
Spring is almost here and with it comes the anticipation of tasty local fruits and vegetables. But, have you ever bitten into a piece of fruit, one that you have eaten many times before, and your mouth started to itch or tingle? You might have thought there was a pesticide, or some other chemical, on the fruit that was to blame. Or, perhaps you have ordered a meal at a restaurant that was followed soon after by cramps and diarrhea. The natural assumption is that there was something bad in the food that made you sick.
In both of those cases there may have been nothing at all wrong with your food. You may have Food-Pollen Syndrome.
The return of Spring brings blossoming flowers and rising pollen levels. If you are one of the millions of Americans who suffer from pollen allergies, your body may also react to certain foods with the same allergic reaction.
Allergies to pollen are usually due to a reaction by the immune system triggered in response to exposure to certain proteins present on the pollen grains. When pollen is inhaled, histamine is released in the lining of the respiratory tracts causing the familiar symptoms such as sneezing, congestion, scratchy throat, or wheezing.
In 30-70% of people with nasal and respiratory allergies, Food-Pollen Syndrome occurs because some foods contain proteins that are very similar to those found in pollen. If your nose reacts to a particular pollen, your digestive tract lining may react to foods that share those traits. The most common reaction is an itching or burning sensation in the lips, mouth, ear canal, or throat. Swelling of the lips and tongue or a sensation of tightness in the throat can also occur. If the offending food is not destroyed by acid once it reaches the stomach there is a good chance that there will be more symptoms from histamine release lower in the intestinal tract. Indigestion, cramping, vomiting and diarrhea can all happen soon after eating foods that cross-react with your pollen allergy.
It is easy to confuse this reaction with food poisoning. However, most types of food poisoning take hours to develop. The ingested bacteria need time to multiple in the gut. (One exception is staphylococcal food poisoning where the reaction occurs not because of a growing infection but because of toxins that were released into the food prior to eating it as a result of poor handling.) Allergic reactions usually occur very rapidly, within minutes of eating a trigger food.
Allergic reactions to your food may be more common as the pollen levels in the air rise. As your immune system becomes more sensitive to exposure to these proteins in your respiratory tract, you may find that foods that don’t cause you a problem at other times of the year now provoke symptoms.
The specific foods that bring on allergic reactions are connected to the type of pollen allergy you have. For example, those with springtime allergies due to tree pollen may find they get an itchy mouthy when they eat plums, peaches or apples. If you have ragweed allergies you may have problems with melons and cucumbers.
Some of the common food sensitivities that can occur with various allergies are:
The proteins in foods that cross-react with pollen and cause Food-Pollen Syndrome are usually destroyed by cooking. So, most of the reactions are caused by eating raw foods. However, there are exceptions to this rule. Celery and nuts can cause reactions even after being cooked.
Because the reactions occur so soon after exposure it is difficult to try to prevent the symptoms with medications. They just won’t have time to work effectively. Fortunately, the symptoms are usually more of an inconvenience or discomfort than a danger. If you are allergic to ragweed and eating watermelon just makes your lips tingle a little, you don’t have to stop eating watermelon.
If your symptoms are more severe then the list above might help you to identify which foods may have set off reactions in the past and you should try to avoid those items. In some cases, treating the underlying pollen allergy with treatments such as desensitization injections (“allergy shots”) may also decrease the food reaction.
So, before you blame an upset stomach on a bad meal at a restaurant or decide you have to eat organic produce because you think you are reacting to something on the skin of your fruit, think about whether you may have Food-Pollen Syndrome.