Food Sensitivity and Food Allergy: Know the Difference

The topic of food sensitivity is often confused with a food allergy because both are related to adverse reactions to food. Simply put, our body produces different types of antibodies, each of which does something slightly different.     

Take the case of IgE antibodies. Food allergy, an IgE reaction, is a more severe and immediate reaction of the body to a certain kind of food. The most severe allergic reaction is anaphylaxis, like peanut allergies. When we talk about food allergy, it always involves an immunologic hypersensitivity, specifically an immunoglobulin-E or IgE reaction. This food reaction is immediate and severe and can also be life-threatening.    

On the other hand, IgG is a delayed antibody that may take several hours to even a couple of days to react. This scenario makes it difficult to single out which food is causing the inflammatory responses or symptoms.    

While eating foods you’re sensitive (not allergic) to can also cause discomfort, it is not as severe and life-threatening as a peanut allergy. The 3-cheese pizza you ordered and ate with your friends a couple of days ago could have contributed to your headache two mornings after.    

It’s important to note that food allergy and sensitivity are immunological. In summary, food allergy is IgE- mediated, while food sensitivity is IgG-mediated.     

What does this mean?    

An IgE reaction or food allergy causes histamine release, producing an immediate hypersensitivity and possibly a severe reaction. IgG reaction, or food sensitivity, is accompanied by the binding of complement to IgG food antigen complexes, causing an inflammatory response.    

IgG reactions may not be immediately evident and can take hours to days to cause inflammatory-related symptoms like headaches, migraines, fatigue, brain fog, or joint pain.    

On the other hand, IgE food reactions are allergic reactions to food that often manifest quickly in symptoms like severe itching, hives, and swelling. This reaction requires immediate medical attention, while an IgG food sensitivity reaction typically causes tolerable discomfort.     

How do I know if I am sensitive or allergic to a particular food?    

Food allergies usually are very evident at an early age.  

As for food sensitivity, IgG food sensitivity tests are now available in the market. It detects IgG antibodies in your blood against specific foods. A positive test means exposure to the food, and your immune system reacts negatively to the food.   

Specifically, positive could mean moderate, high, or very high reactivity. If you have increased reactivity to certain foods, a food sensitivity test, in the form of an at-home finger prick blood test, can help narrow down the offending foods you may want to remove.    

Once your blood sample is in the laboratory, it will be exposed to antigens from potential food allergens to check for a possible reaction. If such is the case, your antibodies will bind to the foods’ antigens.   

When the test results reveal potential food sensitivities, you can decide which foods you may want to avoid and check if your food sensitivity symptoms improve.    

Many people with IgG food sensitivities are not aware they are sensitive to a certain kinds of foods. Their food sensitivities can go undiagnosed throughout their lifetime. The reason is that many symptoms related to IgG food sensitivities like headache, migraine, fatigue, bloating, and brain fog are blamed on other factors and are not associated with food reactions.    

The good thing about food sensitivity or IgG testing is that it gives us a clearer picture of what’s happening to our bodies and allows us to explore safe options and make informed decisions regarding our food choices. Call it a problem-solving process using elimination or isolation.   

When we actively change our diet by eliminating the foods, we are highly reactive to and pay attention to what happens, and we are more equipped to decide what to keep and what to let go. When we eliminate all the potentially offending foods causing inflammation, we give our bodies a break, usually about a month and a half, to help our bodies recover. Observing the changes at this stage is essential, as it is a slow improvement process.    

Now, what’s next?     

Most people feel that once you eliminate the foods shown to be highly reactive and after some time you see improvements in symptoms, you can reintroduce foods one at a time. At this point, you will either feel no difference, feel better, or feel worse. As the gut lining improves and becomes less inflamed, you may tolerate adding some of the offending foods. Retesting is sometimes recommended for complicated situations.   

More than anything, the knowledge you gain from eliminating and reintroducing foods allows you to discover something undeniably substantial: self-awareness. The more aware you know how your body works, the more confidently you can take the next steps.