Food Sensitivity Overview

Updated: May 2019

When learning about histamine intolerance and mast cell activation, it helps to step back and take a look at the big picture of food sensitivity. In the last few decades, knowledge about food sensitivity has grown tremendously. This knowledge has provided some answers but has opened up many more questions. Food sensitivities are more complicated and diverse than once thought. 

Knowledge is Like an Iceberg

Icebergs have a small part above the surface and a large part, hidden under the water. I’ll explain how this relates to food sensitivity knowledge in the following video.

Searching For Answers That Are Below the Surface

Clients with mysterious food sensitivity symptoms, are often searching for exact answers about the cause of their symptoms and exact treatment. But in most cases, we don’t have those answers and clients are searching for answers that don’t exist. The search for these illusive answers can cause more stress and suffering than the physical symptoms. Accepting that you may be suffering from a condition that is largely “under the surface” and that you may not find exact answers, can help you let go of a frustrating search. The good news is that you can find helpful treatments or lifestyle changes through systematic experimentation - even if you don’t know the exact cause.

Frustrated clients often turn to food sensitivity testing to get answers, but for reasons discussed in the next article, I would not suggest this.

Food Allergy and Food Intolerance

It’s important to remember that food sensitivity is a reaction to a compound within the food, not the food itself. The best example is the difference between milk allergy and milk intolerance (lactose intolerance). With an allergy, the immune system is reacting to a specific milk protein (but everything else in the milk is okay). With lactose intolerance, the milk sugar (lactose) is the problem.

I’ve listed the most common food sensitivity conditions below. Coming back to our iceberg analogy, this is the “above the water” information. If your food sensitivity symptoms do not fit into one of these categories, you may be suffering from a “below the surface” condition. Hopefully, we will know more in the future. Even if you don’t know the exact cause of your symptoms, you can find helpful treatments or lifestyle changes through systematic experimentation

Food Allergy

Food allergies are an adverse reaction to a food that is mediated by the immune system. Our immune system protects us with inflammatory chemicals to kill harmful germs.  If the immune system mistakes a food protein as harmful, inflammatory chemicals are released and cause inflammatory symptoms. I’ll briefly describe the most common food allergies below.  

Food allergy symptoms are usually consistent (e.g. you react with similar symptoms each time you eat the food).

This is not a single condition, but an umbrella term for several conditions where a food protein (usually milk or soy) inflames the digestive system. At the current time, most cases are infants reacting to formula and the allergy is outgrown in several months.

What’s happening in the body: The immune system produces IgE antibodies against a food protein, and the IgE attaches to mast cells in the digestive system. In the case of peanut allergy, the immune system produces peanut IgE. If the mast cells encounter peanut, they will activate (release inflammatory chemicals).

Mast cells are like tiny balloons filled with inflammatory chemicals. They are found throughout the body but are concentrated in certain areas, such as the digestive system. Mast cells are an essential part of normal immune function but are also at the basis of many allergic reactions.

Typical IgE food allergy symptoms include:

  • Digestive – sudden vomiting and/or diarrhea,
  • Respiratory - wheezing, difficulty breathing (asthma),
  • Skin - hives, swelling, itching, tingling in the mouth or face,
  • Other -headache, impending doom.

Severe symptoms (anaphylaxis) can include a sudden drop in blood pressure (shock) and severe asthma.

Timing between food intake and symptoms: Symptoms usually occur within minutes to a few hours after eating the food.

Diagnosis: The connection between the food and symptoms is usually obvious because the timing is quick, and symptoms are consistent (occur every time the food is eaten, even in small amounts). The diagnosis is based on the client’s reported symptoms and blood or skin tests -confirming IgE to the specific food or food protein. If the diagnosis is uncertain, the physician may do a medically supervised food challenge (see IgE Food Allergy).

Treatment: The food allergen is entirely responsible for the symptoms. The patient will not have symptoms if they avoid the allergen.

What’s happening in the body: The immune system produces IgE against a protein in an environmental substance (e.g. plant pollen). Plant foods (such as fruit, vegetable, nut, etc.) have similar proteins and eating these plant foods may lead to symptoms. The most commonly recognized condition is oral allergy syndrome, which causes inflammation and itching in the mouth and face.

Timing between food intake and symptoms: Symptoms usually occur within minutes to a few hours after eating the food.

Diagnosis: There are no laboratory tests to directly diagnose food allergy cross reactions.

Treatment: The food allergen is entirely responsible for the symptoms. The patient will not have symptoms if they avoid the allergen.

What’s happening in the body: In genetically susceptible individuals, the immune system produces autoimmune antibodies in response to gluten ingestion. The autoimmune antibodies travel throughout the body and cause damage to a variety of organs. Gluten also damages the nutrient absorbing surface of the small intestine, so patients often suffer from malnutrition (e.g. anemia, osteoporosis, etc.).

Timing between food intake and symptoms:  Damage to the body occurs over time, so the connection between gluten and symptoms is not usually obvious. However, after following a gluten-free diet, patients often experience immediate discomfort if they eat gluten.

Diagnosis: The diagnosis starts with a blood test to detect autoimmune antibodies. If the blood test is positive, patients see a gastroenterologist for a small bowel biopsy. The patient must be eating gluten a few months before the test for it to be accurate. See Test for Celiac Disease before Restricting Gluten.

Treatment: Gluten is a protein found in wheat, barley and rye. With a strict gluten-free diet, the autoimmune antibodies disappear, and the small intestine heals. Gluten is entirely responsible, and symptoms will disappear after a few months with a strict gluten-free diet (in most cases).

Food Intolerance

Food intolerance is an “umbrella term” for many different adverse food reactions that are not mediated by the immune system.

Food intolerance is often inconsistent (you react differently on different days).

What’s happening in the body: Lactose (carbohydrate in milk) is broken down by the lactase enzyme in the digestive system. If the lactase enzyme is absent or not functioning well, lactose is not broken down and absorbed, so it travels on to the large intestine. Bacteria ferment the lactose, leading to gas, bloating and diarrhea.

Timing between food intake and symptoms: It takes time for the lactose to travel to the large intestine, so the symptoms (diarrhea, gas, bloating) start in about 4 – 6 hours after consuming lactose.

Diagnosis: Your doctor can order lab tests, but the results don’t always correlate with symptoms. The best diagnosis is eliminating lactose and then reintroducing it.

Treatment:  Many patients can eat small quantities of lactose without symptoms and may be able to increase their intake overtime (i.e. lactase enzyme may gradually increase with lactose consumption). The lactase enzyme can be purchased in drops or tablets at most pharmacies.

What’s happening in the body: The pathology is very similar to the description for lactose. In fact, lactose is one of the FODMAP carbohydrates. Other FODMAP carbohydrates include fructose, oligosaccharides, etc.

Timing between food intake and symptoms: The symptoms (diarrhea, gas, bloating) usually start about 4 – 6 hours after eating poorly absorbed carbohydrates (but this can vary).

Diagnosis: Currently, there are no accepted diagnostic laboratory tests. The self-diagnosis is based on symptom improvement with a short-term low FODMAP diet (no more than 4-6 weeks).  If symptoms improve, each FODMAP group is slowly reintroduced to pinpoint the problematic foods. A specialized dietitian can help you through this process.

Treatment: Avoiding the identified carbohydrates improve symptoms. However, many other factors affect digestion, so patients often continue to experience symptoms.

What’s happening in the body: Dietary histamine is broken down in the digestive system. If this process is compromised, dietary histamine will not be broken down and enters the blood. Increased blood histamine can lead to puzzling allergy-like symptoms.

Timing between food intake and symptoms: Timing is variable. Large quantities of food histamine may lead to immediate symptoms. Smaller quantities may slowly accumulate over several hours.

Diagnosis: Currently, there is no accepted diagnostic laboratory tests. The self-diagnosis is based on symptom improvement with restriction and return of symptoms with reintroduction.

Treatment: A low histamine diet and diamine oxidase enzymes will reduce symptoms if the patient truly has dietary histamine intolerance. However, many factors affect blood histamine levels, so diet changes rarely eliminate symptoms.

What’s happening in the body: Food is a symptom trigger for many mast cell disease patients, but the exact mechanism is unknown. Some mast cell patients find a low histamine diet helpful. “Histamine releasing foods” are theorized to cause direct activation of mast cells in the digestive system (see Dietary Histamine Intolerance for more details).

Timing between food intake and symptoms: Some clients experience immediate, anaphylactic-like symptoms, and others experience delayed symptoms.

Diagnosis: The physician specialist considers clinical symptoms, laboratory results and response to medication. Unfortunately, there isn’t a yes/no test available, so a definitive diagnosis is not possible in some cases. Observation and experimentation can help determine specific food triggers, but they can be inconsistent, so it is difficult to pinpoint exact triggers.

Treatment: Mast cell disease is treated with medication to stabilize mast cells (so they are less likely to activate) and other medication to block the effect of inflammatory mediators. Trigger avoidance (including food triggers) is an important part of treatment.

 

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