Science at Work: Food Allergies, Food Intolerances, and Mysterious Diets

FAF_-_Big8food-allergens.34290002_stdToday we unravel the following:   what is the difference between food allergies and food intolerances, and why are so many people giving up foods like gluten?

Food Allergies

Allergies of all kinds happen when the body’s immune system reacts to an innocuous substance (in my case, grass, in my daughter’s case, peanuts) as though this substance is poisonous.  Most environmental allergies cause symptoms like itchy red eyes, runny nose, cough, and sometimes hives.  I spend the entire spring season feeling like I have the worst cold imaginable.  But no matter how wretched I feel, I know that I am not going to die from my grass allergy.  Food allergies, on the other hand, can be fatal.

Food allergies are tricky because they often cause the body to go into anaphylactic shock (this is especially common with peanut, tree nut, and shellfish).  Food Allergies For Dummies, a book I highly recommend, defines anaphylaxis as “An immediate, severe, and sometimes fatal allergic reaction that can cause respiratory failure or shock due to an extreme drop in blood pressure”.  Basically, when you die of anaphylactic shock, you die of cardiac arrest or because your throat swells shut so tightly that it suffocates you to death.

The most common food allergies in the United States are to peanuts, tree nuts, shellfish, soy, dairy, eggs, fish, and wheat.  People living with food allergies must carry epinephrine at all times (in the form of an EpiPen or an Auvi-Q) and must use great caution especially when eating out.  According to F.A.R.E (Food Allergy Research and Education), up to 15,000,000 people in the US have food allergies, and a person goes to the emergency room for treatment related to food allergy reactions every three minutes.  According to F.A.A.N (Food Allergy and Anaphylaxis Network) there are an estimated 100 – 200 deaths in the US from anaphylaxis each year.

There are a couple of things to keep in mind about these statistics.  One is that they are controversial.  Some think food allergies are under-reported, because they may be mis-diagnosed.  Others think they are over-reported, because they may be being mis-diagnosed in the opposite direction.  Some people try to diagnose themselves and may have an intolerance as opposed to an allergy.  There are also concerns about bias, since the leading food allergy advocacy groups that do a lot of the statistical research also have a monetary interest in keeping the issue alive.

The other thing to keep in mind is that the statistics don’t reflect the whole picture.  On the one hand, deaths from food allergies are clearly very rare, especially when you take into account the fact that there are 313.9 people in the US (as of 2012).  But this doesn’t reflect why the death rate is so small amongst such a high population of sufferers.  Most people with severe food allergies survive not because their allergies are inconsequential, but because these people are unrelentingly careful, just as most people don’t die from chugging rat poison out of a bottle because we know that will kill us and therefore we avoid consuming it.

Food Intolerances

Food intolerance is when the body can’t digest a food properly.  One of the most common food intolerances is to lactose (which is found in dairy products).  Lactose intolerance is different than an allergy to milk.  In lactose intolerance, the body doesn’t make enough of an enzyme called lactase to properly break down lactose, and this causes gas, bloating, and other stomach problems.  Another common intolerance is to gluten, and this occurs when the body can’t break down the proteins found in gluten.  Celiac disease is a specific kind of intolerance in which “gluten ingestion triggers your white blood cells to attack the lining of you small intestine”.  Other common food intolerances are to sulfites (these can cause asthma and headaches, and are the reason that migraine sufferers are often told to avoid wine and chocolate), and, to a much lesser degree, food additives.

A food intolerance can be mild or severe.  Let’s say you have a friend who is lactose intolerant.  She might tell you that since it’s her birthday she’s going to have just one piece of pizza.  She may have no problems with a small amount of the problem food or she may have just very mild symptoms – one that she avoids most of the time but is willing to live with occasionally when she really craves something, like that one piece of pizza.  But, it’s also possible that your friend absolutely can’t have any lactose at all.  She may experience severe vomiting or diarrhea after just the smallest exposure to lactose.  So do not take food intolerances lightly unless you want your friend to vomit on your shoes.

Main Differences Between Allergies and Intolerance

Food allergies and intolerances can be confusing, because often people with intolerances will say they have allergies – sometimes because they don’t understand the difference, but usually because it’s simpler and it’s easier to get people to take your food issue more seriously when you call it an allergy.  And basically, the deal is the same – if you eat the offending food, you will feel awful.  For practical, non-medical purposes, the main differences to remember are that intolerances aren’t fatal but allergies sometimes are, and that jabbing your friend who has an intolerance with an EpiPen isn’t going to help.

  • Someone with a food intolerance can often have small amounts of the problematic food.  To someone with food allergies, especially someone with severe allergies, even trace amounts of the allergen can be fatal.
  • Food allergies involve the immune system and food intolerances do not (Celiac disease involves the autoimmune system, but not in the same way that an allergy does).
  • If someone is having an allergic reaction, they can be treated with epinephrine and/or an antihistamine (not always with success).  These won’t help someone with an intolerance.

Avoiding A Food For General Health Reasons

Lately, an increasing number of people have been avoiding various foods based on ideas that these foods may be bad for everybody or may be bad for them in a previously undiagnosed, undramatic way (meaning – they cause chronic problems, not sudden bouts of gastrointestinal distress).  The most common one you’ll hear referred to is gluten.  Some research suggests that our bodies simply aren’t evolved to properly digest gluten (this research is, to use a scientific term, iffy).  Some people swear that cutting out gluten (or sugar, or dairy, or soy, or some combination) makes them feel better – thinner, more energetic, and healthier overall.

So what’s up with these mysterious diets?  Do they work?  There’s no definitive science that says that you should avoid a kind of food unless you have a concrete reason to – a diagnosed allergy or intolerance.  So what’s going on with you friend who says she feels better since she quit eating gluten?  Well, maybe she really had a low-grade intolerance.  Maybe she feels better because cutting out one or more staple food items makes her eat a more varied menu of whole foods with mainly fruits and vegetables and proteins – hard to go wrong with that.  Maybe she is just being trendy – but I’m being trendy when I spend $3.50 on my cookie crumble frappachino, and nobody gives me a hard time about that.

So respect your friends’ food choices and limitations, whether they are a matter of life and death (as in an allergy), a matter of severe physical distress, (as in an intolerance), or an experiment, (as in elimination diets that aren’t treating an identifiable problem but may or may not be beneficial overall).

Science at Work: Finding a Cure for Food Allergies

discovery_medicine_no_65_stephen_c_dreskin_figure_2A child in my area, Natalie Giorgi, died last weekend of the same food allergy that my daughter has (peanut).  My first impulse was to rant and rave about all the people who have died from food allergies, but a few minutes of googling that for gory details had me curled in fetal position and whimpering.  So instead here’s some news about possible upcoming treatments for peanut allergies.  It’s time for…SCIENCE!

Allergies happen when the immune system reacts to a food protein as though it is a threat.  Some allergies can be cured or  lessened by giving the patient very small doses of the allergen, and increasing the dose gradually until the body learns to accept the allergen.  As a kid, I had shots of grass pollen in my arm once a week until I could tolerate being outside in the Spring (I had, as a side effect, developed a strong aversion to doctor’s offices).  The tricky thing with food allergies is that the body reacts so violently to the allergen that it is difficult to desensitize the patient without, well, killing them.  But scientists are getting better at finessing the tiny, tiny doses that they have to start with, and experimental methods are making waves.

I cannot over-stress the fact that current treatments are in trials, and are conducted under immediate medical supervision.  Do NOT try this at home.

Most experimental treatment involve giving the patient proteins by mouth.  In sublingual immunotherapy, the patient holds some liquid containing peanut protein under their tongue for two minutes and then swallows this.  After 44 days of this treatment, patients showed significant improvement, although it was not as high as the experimenters had hoped.

In oral immunotherapy, you swallow some peanut protein, usually a higher amount than is involved with sublingual therapy.  The beneficial effects seem to be greater than those experienced by people who try sublingual immunotherapy, but the side effects are greater as well.

The new exciting thing is a therapy involving wearing a patch.  The patch would contain a peanut protein and gradually desensitize the wearer.  The idea is that because the proteins would be absorbed through the skin, there might not be the side effects that are associated with oral therapies.  It’s also much more convenient to wear a patch as you go about you daily life than to visit the doctor every day for a month and a half or more, as in sublingual therapy.  Eventually you take the patch off, and ta-da!  You are cured.

One research team has been working on a shot, Xolair, that blocks allergic reactions by blocking the antibody that causes the reaction.  Xolair is already approved for treating asthma.  Patients get a series of shots, and then start immunotherapy.  This seems to be helping kids who have extremely severe allergic reactions to many foods instead of a single food allergy.  It seems to work quickly and help with a range of allergens – but the process can be difficult and painful as many kids have mild to sever reactions during the course of the oral immunotherapy.

My daughter’s allergist predicts that we’ll have a cure for peanut allergies that is widely available in about five years.  For the child from my town who died last weekend, that is too late.  I have been blessed in finding nothing but kind support in my family and community, but not all people have been so lucky.  Please support those around you who have food allergies or who are parenting a child with food allergies even if you think they are crazy, or trendy, or over-protective.  Probably some of them are, but most of them aren’t, and our kids deserve the protection of their community.  This quote from The New York Times, by Melanie Thernstrom, does a beautiful job of summarizing the anxiety of being the parent of a child with a food allergy:

Food allergies are a peculiar disease, because most of the time the child is not sick — indeed, she may be bursting with health — but is in omnipresent danger. Statistically the chance of dying is slight. Although the number of emergency-room visits for anaphylaxis caused by food has gone up significantly in the past decade — to as many as 90,000 in a year — only 100 to 200 people die (although statistics are difficult to collect because such deaths are often coded as cardiac arrest). Even for a severely allergic child like Tessa, the mortality rate is estimated at roughly 1 in 1,000, because parents of such children tend to be extremely careful.  But food allergies amplify a kind of fear every parent experiences — of a child dashing suddenly into the street and, just like that, being gone. Your child is always playing near a precipice that is visible only to you: you may be able to keep her from falling off, but you can never move her away from the edge.

My daughter has a great life.  She has a family who adores her and an excellent school.  All her needs are met and quite a few of her wants.  She has every advantage that a middle-class kid can have – and that’s a lot.  There are so many kids who don’t have these advantages, and don’t have even their most basic needs met – not just in other countries, but here, in my country, in my city.  I never forget that.  I never stop appreciating our life and I hope I never stop working to help kids who need so much more than what life has given them so far.

But you know what, Natalie Giorgi had all the same advantages that my kid has, and she still died.  My child has a lot of good things going for her, and yet we live on the brink of disaster all the time.  My child is on a precipice.  Help me keep her from falling.  Thank you.