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Dr. Ayala

Dr. Ayala
Philadelphia, Pennsylvania, USA
V.P. Product Development
Herbal Water
I’m a physician (Pediatrics and Medical Genetics), artist, and mother of 3 school age active kids. I recently co-founded Herbal Water Inc. (www.herbalwater.com) with my husband, Albert. I am a serious home cook, and love to entertain. My expertise is vegetarian food (I have been a vegetarian all my life). I strongly believe that eating healthy and enjoying good food go hand in hand. My main interests are science, nutrition and art, and I am overall a very curious person that tries to learn something new every day. Dr. Ayala (Ayala Laufer-Cahana M.D.)


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MAY 24, 2010 7:12AM

Are food allergies really on the rise?

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Nuts 005

A new study in The Journal of Allergy and Clinical Immunology reports that the rate of peanut allergies in kids more than tripled in just ten years.

According to the study, 1.4 percent of kids reported peanut allergies in 2008, as opposed to just 0.4 percent in 1997. The rate of combined peanut and tree nut allergies reported in kids was 2.1 percent in 2008, compared to 0.6 percent in 1997.

Alarming, but before we panic, let’s take a closer look at the study design: This study randomly surveyed more than 5,000 homes in the US by phone, and the allergies were self-reported.

Is self-reporting an accurate way to assess the prevalence of food allergies?

On the one hand, who knows kids’ food reactions better than their parents, right? But when it comes to food allergies, it seems that even medical experts can’t really agree on what makes a diagnosis of food allergy, so parents’ testimony of their kids’ food allergy status (as opposed to asking them a simple factual question, such as “Did your child get a tetanus shot?”) may very well reflect parental heightened awareness of this medical issue (which is definitely on the rise), rather than a true increase in food allergies themselves.

We know less than we think about food allergies

A recent systematic review in the Journal of the American Medical Association shows the complexity and confusion in the field of food allergies. The researchers, led by Dr. Jennifer J. Schneider Chafen, pored over more than 12,000 studies on food allergies—most of which, they found, were poorly conducted. Only 72 studies met the authors’ criteria for scientific rigor, and when analyzing the data the conclusion was, in plain words, that we know much less than we think.

Here are a few surprising issues the researchers uncovered:

There’s no agreement on the definition of food allergy.
The lack of clear definition leads to much confusion between what is a food allergy (in which the immune system is involved) and other reactions that are not immune-mediated, such as food intolerance.

There’s no agreement on how to test for a food allergy, and many tests aren’t definitive. The common tests used to aid in the diagnosis of food allergies aren’t very good at predicting who will actually react to a certain food; test results in isolation (without a good clinical picture and evaluation) aren’t more helpful than a coin toss.

The current gold standard for diagnosing food allergies is the food challenge, during which a physician gives the patient a sample of the suspected allergenic food, and monitors for an allergic reaction. This kind of testing is expensive and requires specialized personnel and therefore isn’t often done (it also isn’t covered by many insurance plans). More commonly used tests are the skin-prick test, during which a dilute extract of the potential allergen is placed under the skin, and a blood test determines the presence of food-specific allergic antibodies known as IgE.

Unfortunately, neither of these two tests is very specific; in fact they aren’t definitive at all. Kids with non-specific symptoms, such as a rash or digestive complaints, and a positive skin-prick or blood test actually have less than a 50 percent chance of indeed having a food allergy.

If definition and testing aren’t clear-cut, it becomes quite evident that the prevalence of food allergies is hard to assess.

The researchers found that in general, studies that used self-reporting found much higher rates of food allergies than studies that used the skin-prick test, IgE blood test and food challenges. The authors comment that it’s even hard to say for sure whether food allergies are in fact on the rise because the data is so inconsistent.

Their best estimate is that the prevalence of food allergies is anywhere between 1 or 2 percent and 10 percent, which is a difference of 500 percent or more. So much for accuracy.

It is generally the feeling in the medical community that food allergies are indeed on the rise, but there’s no doubt that misdiagnosed food allergies are on the rise, too.

And if food allergies are misdiagnosed?

Inappropriate diagnosis of food allergies denies kids nutritious foods and creates unnecessary anxiety around food. Misdiagnosed food allergies also are a waste of money, as specialized diets don’t come cheap.

Over-diagnosis and misdiagnosis of food allergies also may trivialize the seriousness of real, potentially life-threatening food allergies. We all know the story of the boy who cried wolf.

Hopefully, some good news ahead

The way ahead is promising. The National Institute of Allergy and Infectious Diseases is creating comprehensive clinical guidelines for the diagnosis and management of food allergies. Guidelines from a 25-member expert panel are due this fall and will provide much needed direction.

In the meantime let me offer some prudent advice: If you think your child may have a food allergy, it’s best to consult an experienced physician. Over-diagnosis may lead to unnecessary food limitations and undue reduced quality of life, but not taking real food allergies seriously enough and not learning what to do about them can threaten life itself.

Dr. Ayala

Related posts: The gluten-free health fad: the good and the bad - part 1

The gluten-free health fad: the good and the bad-part 2

Want milk? Lactose intolerance shouldn’t stop you

Read more from Dr. Ayala at  http://herbalwater.typepad.com/ Follow Dr. Ayala on  Twitter 


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@Will Azeperak
Well said my friend :)
Good piece Doctor. Ive wondered a lot about this issue as I have noted there are times when I seem to react to certain foods and then at other times I dont. Is that an allergy? Seems to me that would lead to a self reported "Yes" but I really dont think thats the right answer.
There are times, for instance, when I know before I eat chocolate I will get a headache. Other times I know I wont. So that would seem that my body knows its under attack by numerous stressors and is just sending me a little personal note to say "Not now Tim" which I proceed to ignore.
Love your work here. {R}
I have mixed feelings about the seeming rise in food allergies. I'm in my mid 40's and have been allergic to tree nuts all my life. I have the life-threatening kind of allergy where my throat, lips and tongue swell up and which can progress to anaphylactic shock if I'm not careful. On occasion, I also get hives which is how it was discovered back before I can even remember.

Over the past 10 or 15 years, I've noticed a welcome increase in the awareness of food allergies, especially at restaurants. The incidents of me asking waiters about nuts in foods is far less likely to be answered with "only a little", "only on the edge and you can pick them off", or even worse, defensiveness as if I'd criticized the food. Now waiters are more likely to either know or be willing to go check with the kitchen, and are willing to ask the chef to make alterations to the dish if possible. That's the upside.

The downside is exactly what is mentioned in the post: that food allergies are being trivialized and even are downright trendy.

When I was very young, there were no medications available to treat reactions, or at least my parents did not have them. As I got older, Benadryl was available by prescription but I didn't carry it with me. I believe I was in high school when it finally was available over the counter and I started carrying it with me. I didn't get an Epi-Pen until a particularly bad reaction at a company holiday party nearly killed me in my early 30's. I've learned over the years to first of all not panic and second to spit out whatever is in my mouth and third to rinse my mouth repeatedly, and brush my teeth and gargle if possible. That takes care of 95% of the problem right there. I'm lucky in that the second nuts touch my lips or tongue, a distinctive taste, tingling or swelling occurs and I rarely end up swallowing more than a mouthful, if even that. I usually follow up immediately with Benadryl and try to take it easy for the next 24 hours which is generally how long it takes for any swelling to completely resolve. I've never gone to the emergency room, although I probably should have during the holiday party reaction.

My experience has been that it doesn't have to be a dramatic oh-my-god event. I think even small children can be taught to monitor their own bodies for reactions and the foods that they eat for possible problems, and learn to take appropriate steps. The best option is not to even eat or allow yourself to be exposed to the problematic food. My parents did not send notes to teachers or the parents of classmates; for better or worse, they treated it as my problem to deal with. Consequently, I spent a lot of time as a child adamantly telling adults that I couldn't eat their food (you'd be amazed at how many adults got into arguments over brownies with walnuts and insisted that I must, at all costs, at least try one because I'd learn to like nuts if I just tried them), but it's possible to be very stubborn when necessary, even for extremely compliant children like I was.

I understand that parents want to protect their kids but I believe the best thing that they can do is teach their kids how to react. Parents and knowledgeable adults might not always be around. I've learned over the years, through no help from my parents, which nuts cause milder or severe reactions, what foods are likely to contain nuts, and most importantly what measures I can take myself if I eat something with nuts.

The bottom line is, it's not always an emergency, although the potential is always there.
Haha, the glutton intolerance.

I think the answer is the people with intolerance died. But evidently the gene still got passed on - perhaps it's recessive.
@Tim4change: you’re absolutely right. What you’re describing is a reaction, but unlikely to be an allergic or immune reaction.
@ixxidust Thanks for the excellent comment and for sharing your first-hand experience.
Stella - Intolerances are not immediately life-threatening and have more to do with your body just not processing certain things.

For example, I am lactose intolerant, and I have been all my life. I simply can process the sugars in milk. It gives me truly nasty and ugly gastrointestinal symptoms and it hurts like merry hell.

However, lactose intolerance is a matter of degree. Most of us can handle a certain amount of milk sugars. I can handle the milk in a bowl of Corn Flakes, for example, but that's all. If I have an actual glass of milk, I'm begging for trouble. I don't go there, primarily because I hate milk with a passion that most children reserve for broccoli or brussels sprouts.

Cooking converts lactose into something that we lactose-intolerant babies can easily digest. For example, I can have lattes, because the milk has been steamed. The same goes for baked goods and cooked desserts. Cream soups are fine, as long as they've been heated to the right temperature.

I am also allergic to penicillin, tetracyclenes and sulfa. Any of them would be a superb murder weapon if someone really wanted to get rid of me. If I so much as touch most antibiotic ointments with my hands (as in eyedrops for the cat who tried to be friendly with the cactus), my sinuses start to swell, my eyes water and my throat starts to close.

Unlike milk, there is no safe amount of antibiotics for me.

A food allergy is an immune system response--the body mistakes an ingredient in food -- usually a protein -- as harmful and creates a defense system to fight it.

Food intolerance is a digestive system response rather than an immune system response--something in a food irritates a person's digestive system or when a person is unable to properly digest or breakdown, the food. The most common example is lactose intolerance.
So interesting! Two years ago at my son's preschool orientation I was bemused by the reported food allergies. Green beans? RLY? When I asked the parents ("How did you discover an allergy to something I can even get my kid to touch?") I found out that most of the parents (it was a class of about 12) had been through pinprick testing with their kids. I didn't do a scientific survey, but a couple of them told me that their child had never had a reaction to the food listed on their allergy list (and perhaps had never eaten it) other than the pinprick test.

I am not an allergy-denier. I know a couple of kids who have serious allergic reactions to foods. But I don't think doctors are doing parents any favors if they are just randomly testing for food allergies and not explaining that the pinprick test is not definitive.

I also wish that parents would be clearer about communicating the difference between a minor food intolerance or allergy (my kid gets the sniffles when he eats x, for example) and life-threatening allergic reactions. It is a kindness to the other parents who may have your child over for a playdate, and it is also important that the messages of people who have serious allergies aren't drowned out under the deluge of "I had a stomachache once when I ate x" people.
Stellaa, I think allergies are an immune system response. I've read that wheat allergies are more common in Europe, Rice allergies in China and Japan, and Corn allergies more common in Mexico.

In the good old days, I think a lot of people just died. I have a friend with a gluten allergy. She lost 30 pounds and was sick for month and months before it was diagnosed. She was pale, weak, had nausea and diarrhea. Gluten is such a common part of so many foods that she never made the link when she stopped being able to tolerate gluten (she had been a bread eater in the past). I think it would have been labelled a wasting illness in the past and historians looking at past records would have no way of coming to an accurate diagnosis.
Add to that the fact that someone who has lost too much weight and is constantly sick is at much higher risk of dying from some flu epidemic.

Even now, causes of death are hard to pin down. My grandmother was healthy until she got aggressive breast cancer, which metastasized to her bones. Her death certificate lists kidney failure as the cause of death, but that was caused by a combination of cancer drugs and invasive, spreading cancer.
When my brother was a few months old, he came in contact with a peanut butter sandwich which had been cling-wrapped. Shortly afterwards, he had pretty much stopped breathing, came over with a pretty nasty rash, and ended up in hospital for a few nights.

That might be an intolerance, but it's a rather severe reaction. Just to be on the safe side, we call it an allergy.

Side note: he's turning six in a few weeks, and before eating anything he's never tried before, he automatically frowns and asks if it contains nuts. I know something like that shouldn't make me smile, but heh. :)