If you are allergic to a pollen you may be allergic or react to certain foods such as apples, celery, nuts, melons or bananas. Numerous studies have confirmed the reports of people who have pollen allergies reacting to certain foods. The most well described and studied of the food-pollen syndromes is the oral allergy syndrome (OAS) or as it is also called “the burning mouth syndrome” because of the typical reaction noted by affected people. After eating a food that cross reacts with a pollen to which you are allergic, burning or tingling sensations begin in your mouth. Itching, pain, swelling and difficulty swallowing or breathing may occur. True anaphylaxis resulting in total body collapse from shock and death if not reversed has rarely been reported.
Typical pollen allergy symptoms such as runny nose and congestion, itchy watery eyes, and wheezing are also commonly reported. Other symptoms described include nausea, stomachaches, headaches, diarrhea and chest or throat tightness. Very few people are aware of these associations. Most doctors, except a few allergists and gastroenterologists, do not explore patients allergy history in the context of possible food reactions. Educating people about these types of conditions is one of the primary goals of “the food doc”, Dr. Scot Lewey, a practicing gastroenterologist (stomach-intestine specialist).
Ragweed pollen has been shown to be associated with these type of reactions after people eat bananas and fruits in the gourd family such as watermelon, honeydew, and cantaloupe. Pollen from Mugwort, another weed also known as Sagebrush, in the Artemisia family, has been associated with allergic reactions to celery, carrots, fruits in the Rosaceae family (apples, cherries, peaches) and those in the Gourd family (melons). Pistachio, persimmon, peanuts, almonds, sunflower seeds, hazelnuts, lettuce, camomile tea, and honey have also been reported to cause reactions in some people who are Mugwort pollen allergic.
Birch tree pollen is associated with numerous food cross reactions including celery. Cross-reactivity between celery and Birch pollen occurs more in central Europe whereas in Southern Europe celery and Mugwort reactions are more common. A Mugwort-Birch-Celery-Spice syndrome has also been described. People allergic to both Birch tree and Mugwort weed pollen may react to spices like pepper and paprika in addition to celery, carrot, and mango. Birch pollen is strongly associated with food reactions to Rosaceae family fruits (apples, apricots, peaches, pears, cherries), tree nuts (walnut, hazelnut, Brazil nut), legumes (peanut, various beans and peas), members of the Parsnip family (parsnip, parsley, anise, cumin, caraway, coriander) and the potato-nightshades (potato, tomato, peppers).
House dust mite, a serious allergen for many people, cross reacts with mangos, shellfish, bananas, melons, tomato, avocado, papaya, pineapple, peaches, Kiwi fruit and various spices. Kiwi, an unusual fruit in a class by itself, may elicit a reaction in people allergic to Birch trees, Mugwort weed pollen, and latex. The Latex-Fruit Allergy Syndrome is characterized by allergy to foods in the Rosaceae family including almond (classified as a fruit not a nut) and plums, as well as other fruits such as passion fruit, papaya, pineapple, mango, melons, and bananas. It is also associated with reactions to spices such as dill, ginger, and oregano and the nightshades, potato and tomato and chestnuts.
A few articles in scientific literature have reported associations of specific HLA gene patterns to pollen allergy and fewer still have noted HLA DR and DQ gene pattern associations with food-pollen cross-reaction syndromes. HLA DQ genetics are well known in celiac disease. There is also limited published data associating certain DQ patterns with microscopic colitis, collagenous colitis and non-celiac gluten sensitivity. HLA typing may be clinically useful in evaluation and elimination diet recommendations for suspected food allergic, intolerant or sensitive individuals. This type of information will be one of the goals of thefooddoc.com website. A table that lists the common pollens and foods that have been reported to cross-react with those pollens will be posted on the site very soon.
Though extensive research has been done and many of the protein structures contributing to these cross-reactions is known, little is known about these reactions by most of the lay public and many doctors. Seasonal pollen allergies may be associated with more severe reactions. Those with documented cross-reactions or prior OAS reactions may be at increased risk and certain HLA gene or DQ patterns may be associated. People with known or suspected pollen allergies should be aware of these possible food reactions. If you would like further help sorting out if you are intolerant or allergic to certain foods please visit http://www.thefooddoc.com in the near future to undergo a free online assessment and sign up for the online diet symptom diary, updates, and access the free educational content.
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Allergies in dogs seem to have become more and more common over the years. Whether this is just because we are getting better at diagnosing them is debatable, but certainly the pet food manufacturers have had an important role to play in dealing with this phenomenon. Although a food allergy is thought to be non curable, the good news is that with proper diagnosis and management it can be well controlled in virtually 100% of cases.
What is a food allergy?
A more appropriate term for a food allergy is an adverse food reaction. It is where ingestion of a certain ingredient in the diet causes itchiness anywhere on the body and recurring skin or ear infections with Malassezia yeast and bacteria. Food allergies can also cause digestive tract signs too, such as fecal mucus, blood in the stools and increased frequency of defecation. They have also been associated with increased flatulence.
The root cause of these adverse food reactions is unknown, but research points towards an increase in permeability of the gut wall, or a failure of the gut associated immune system. Though it has never been proven that certain breeds are affected worse than others, some breeds do seem to be over represented. The age of onset can range from a few months to 12 years old.
What are the ingredients that dogs are most commonly allergic to?
There are 7 ingredients that are frequently responsible for adverse food reactions:
1. Beef
2. Milk
3. Eggs
4. Chicken
5. Soy
6. Wheat
7. Corn
Statistically, beef and soy are the biggest offenders. Many dogs will be allergic to more than one of these ingredients, and may also be allergic to things in their environment, such as pollen, certain grasses or fleas.
How can a food allergy be diagnosed?
If a dog has had general itchiness that does not lessen in the winter months, recurrent skin and ear infections or intermittent soft stools, it is worth investigating for a food allergy.
There are 3 recognised diagnostic methods:
1. A blood test to measure antibodies to various ingredients.
2. An intradermal skin test where allergens are injected at various points on the skin and the reaction is measured.
3. An elimination diet.
The intradermal skin test is thought to be very inaccurate, and the jury is still out on the blood test. The elimination diet is seen as the most reliable, and the cheapest of the three options. It does however require a motivated and disciplined owner in order to achieve meaningful results.
Elimination Diet
There are three basic elimination diet choices:
1. Home cooked food
This is not generally recommended as it is time consuming for the owner and can also provide an unnatural and nutritionally unbalanced diet. However, if the dog is incredibly fussy and the owner cannot bear to force it to eat a commercial diet, the best ingredients are one of either lamb, fish, duck or turkey, plus one of either rice or potatoes. The two ingredients selected (the former high in protein, the latter a carbohydrate source) should be ones that the dog has preferably never eaten before.
2. A commercial, limited antigen diet
If one of these diets is to be recommended, suitable ingredients would be venison, rabbit or oatmeal. Remember, we are looking for ingredients that your dog has never eaten before, so cannot possibly already be allergic to.
3. A commercial, hydrolysed protein hypoallergenic diet
These contain proteins that have been broken down to the extent that they are no longer capable of causing an allergic reaction. They are often referred to as prescription diets because they are usually purchased via a veterinarian, although they can be obtained over the counter without a prescription. They are significantly more expensive than limited antigen diets, so it is wiser to try a limited antigen diet first as if the elimination diet is successful, the dog will remain on that food for life.
The elimination diet must be given for a minimum of 6 weeks, and possibly up to 10, in order to observe the maximum response. Owners must not give their dog ANYTHING else during the trial period, meaning no titbits, treats or vitamin supplements. For example, many owners do not realize that rawhide chews are made from cow derivatives and that with beef being the most common culprit in allergies, these chews could be the root of the problem. During the trial period, nothing must enter the dogs mouth apart from the chosen diet and water.
If the symptoms in question are intense itchiness, many vets will prescribe antihistamines or steroids during the first few weeks of the trial in order to make the dog more comfortable. If the dog gets better as the trial goes on, and the initial drugs to provide temporary comfort have worn off, then it is suggestive of a food allergy. If this occurs, the dog is then challenged with its former diet to see if the symptoms return and therefore confirm the diagnosis. It usually takes between 3 and 7 days for the symptoms to return after initiating the challenge.
If there is a partial improvement in the dogs condition, it is likely that the dog indeed has a food allergy but also has other allergies at the same time. The dog will then be kept on the elimination diet while other potential allergies are investigated, such as flea bite sensitivity and atopy. These can be checked for via intradermal testing or blood tests.
If a food allergy is confirmed, the owner can either continue to feed the same food given during the elimination trial indefinitely, or can persevere with dietary trials by introducing the 7 most common allergic ingredients (see above) one by one until it is ascertained exactly what the dog is allergic to.