By special request, SkepticRD is going to write about something that I deal with daily: food in-tolerances.
First, a little refresher on the difference between a food allergy and a food intolerance. A food ALLERGY is defined as an IMMUNE SYSTEM reaction that occurs soon after eating a certain food. Said reactions can include digestive problems, hives or swollen airways. Symptoms can be mild or severe or even a life-threatening reaction
known as anaphylaxis. Even a tiny amount can cause a reaction. A food INTOLERANCE, on the other hand, often comes on gradually and doesn't involve an immune system reaction. Digestive symptoms like diarrhea and cramping (I think the delicate term is "intestinal distress") are often present.
The good news for skeptics is that when it comes to food allergies, science has come up with some good ways to test for it, particularly if you are visiting the doctor (or the emergency room!) during or shortly after a reaction. Your average primary care doctor can order a blood test to look for Immunoglobin E (IgE). If this is present, chances are you are having an immune reaction. The bad news, on the other hand, is that if you visit the doctor when you are not having a reaction, or haven't eaten what you suspect is the offending food for some time, then the IgE may not be present and you may come up "negative" and have to spend more time figuring out what is going wrong. The other bad news is that IgE is usually triggered by proteins in several foods: peanuts, tree-nuts, shellfish, fish, eggs, wheat, and milk. So what if you tend to eat a lot of foods from that category, you might have a difficult time figuring it out. Keep in mind, however, that true food allergies can be life threatening, so it's worth the time and the blood drawn to save your life! You very likely also need a prescription for an "epi-pen" to carry with you to prevent life threatening reactions, or you might just be able to get away with taking anti-histamines. And you of course will also have to start educating yourself about where the offending proteins might be hiding so that you don't innocently eat something and have a reaction!
Some people have had another type of allergy testing done known as a "skin prick test" where a small amount of the suspected problem substance is placed on your arm or your back and then your skin is pricked with a needle to place it under your skin. Unfortunately, however, this test is unreliable when confirming food allergies.
When it comes to "diagnosing" food in-tolerances though, skeptics like me start to have some "stomach upset" simply because the science becomes sketchier and sketchier. One of the problems is that many times the list of symptoms denoting a problem with a particular food or group of foods is rather general and vague. Yes the list made include gastro-intestinal problems like flatulence, cramping, nausea, but sometimes you will also see things like "foggy headedness" and "achyness" and "low resale value on your home." (Just kidding!). Is the "foggy head" because you have a food intolerance or is it because your new born baby is keeping you up at night? Also, by eliminating problem foods you may be activating our friend the placebo effect. In other words, once you stop eating a particular food, your belief that the food was the problem might be enough to abate your symptoms. Of even if you try to incorporate that food again, your belief that the food is a problem might cause a reaction. (Aren't our human brains wonderful!)
So what is a skeptic to do when contemplating food in-tolerances? Here are the Skeptic RD suggestions to be as scientific as possible.
1) Ask yourself if anyone in your family has KNOWN problems with a certain food. Not just a vague "I think Aunt Margaret had a problem with nuts." For example, I have a cousin who has dermatitis herpetiformis, also know as "gluten rash" diagnosed by IgE and skin biopsy. When I started to have digestive issues, I put gluten on the priority list to eliminate. Lactose intolerance also tends to run in families.
2) Keep a food and symptom diary for at least two weeks. Note not only what you eat, but how much. If you do eat any processed/boxed foods, save the label for later reference. If you have symptoms after eating at a restaurant, call them later to get a list of ingredients for what you ate.
3) Think about the above "common food allergy" list above.
4) Once you think you've narrowed down what the offending food might be, eliminate all sources of that food for at least 2-4 weeks.
**Sidebar. Yes the "elimination diet" might trigger the placebo effect. But if your symptoms are very aggravating, you may want to take that risk. SkepticRD was eating a lot of dairy and having gas, bloating, etc. Then after a few dairy heavy days, including a trip to the Cheesecake factory, I became violently ill. I know nausea and vomiting aren't on most people's list of fun things to do, but I REALLY hate being sick. It was worth avoiding dairy for two weeks to not feel that way again any time soon!
5) Try reintroducing that food in a small amount. Preferably on a day off of work in case you do have symptoms. See if your symptoms resume. If they do, you MIGHT be intolerant.
6) Think about other reasons why you might need this food or groups of food out of your life. I know I was one of those people who could not eat "just a little bit" when it came to bread, pasta, crackers, etc. The pigging out led to a high calorie intake which was not so good for my weight, and since I have Type 2 diabetes on both sides of my family, the contribution to insulin resistance wasn't so good either. There are other reasons for people to limit grains to, but that's another blog post for another day!
7) Keep in mind too that just because you eliminate a particular food or food group, it doesn't mean you are going to become deficient in certain vitamins and minerals. If you don't do dairy, there are plenty of ways to get calcium and B vitamins elsewhere. If you don't do gluten or grains, there are plenty of other foods to eat to get the nutrition that you need.
8) Start researching all the different sources of that food or food groups. It's possible that you might be able to do small amounts of that food or trace amounts, or you may have to avoid completely.
Finally, I would recommend that you be very careful when listening to the anecdotes from others. Don't get me wrong, I love getting new recipes for dairy/gluten/soy free foods to try, but because there are a lot of placebo effects running around, you want to limit your internet diagnosis as much as possible!