IgG vs. IgE antibodies: understanding the differences

IgG and IgE antibodies are both part of the immune system, but they are associated with different types of food-related reactions. IgE reactions are typically linked to immediate food allergies, while IgG responses may be associated with delayed food sensitivities. Here’s a quick comparison:

Category	IgG	IgE
What it may indicate	A possible delayed food sensitivity response	A possible immediate food allergy response
Typical timing	Symptoms may appear hours or even days after eating a food	Symptoms often appear quickly after exposure to a food
Common symptoms	May include bloating, headaches, fatigue, or digestive discomfort	May include hives, swelling, itching, wheezing, or anaphylaxis
Best used for	Exploring possible food sensitivities	Helping identify potential food allergies

Before explaining the differences, let’s discuss exactly what IgG and IgE are—protective antibodies.

When the body judges a foreign substance as dangerous, the immune system fights back just as if it was fighting an illness.

The body’s weapon of choice? A class of antibodies known as immunoglobulins.

Depending on the severity of the reaction, different immunoglobulins are used. The body’s three food-related immunoglobulins include [1]:

• Immunoglobulin E (IgE) – A rapid immune response that can be triggered by food
• Immunoglobulin G (IgG) – A more delayed and potentially milder immune response that can be triggered by food
• Immunoglobulin A (IgA) – An antibody that can support the immune functions of mucous membranes

IgE and IgG tests could be the key to unlocking additional food-related insights.

If you’re facing stomach grumbles or headaches at inconsistent times, you might be experiencing a food sensitivity.

Though science isn’t sure of the exact mechanisms that cause food sensitivities, IgG antibodies are believed to lie somewhere near the center of the issue.

Let’s explore the typical signs of an IgG reaction.

IgG symptoms

The easiest way to identify an IgG-related food sensitivity? The symptoms.

IgG-based immune reactions tend to be much slower than those associated with allergies [2]. However, that doesn’t make food sensitivities any less bothersome.

If you suspect you may have a food sensitivity, consider taking the Everlywell at-home Food Sensitivity Test.

Common foods for IgG testing

At the end of the day, almost any food can trigger a sensitive reaction—it all depends on your unique biological system. But for most people, these foods are the common culprits behind IgG-related intolerances [3]:

• Lactose (or dairy)
• Eggs
• Peanuts
• Shellfish
• Corn
• Soy
• Gluten
• Yeast
• Coffee

To discover food sensitivity triggers, an IgG blood test can point the way. After receiving the results, it’s time to try a two-part elimination diet or temporary elimination and add-back challenge. In other words, you can try eliminating and slowly reintroducing a portion of food to your plate. This step can help determine if that food is truly the cause of an IgG-related food sensitivity.

Immediate hives? Instant rashes? Difficulty breathing after eating? Any of these food allergy symptoms could signal that you’re facing an IgE immune response.

IgE antibodies are the body’s primary immune response against a foreign substance. When the immune system sees an ingested, inhaled, or even touched substance as a threat, it will quickly send IgE antibodies to trigger a direct allergic reaction. Usually, this reaction is more severe and more immediate than symptoms that occur with food sensitivities.

IgE symptoms

Severe allergies tend to be obvious—they’re usually debilitating or even fatal. But when symptoms are mild, it can be tough to determine if they are a sensitivity or an allergy. That’s when inspecting for common IgE reaction symptoms can help [4]:

• Breathing issues (wheezing, heavy breathing, triggered asthma)
• Skin inflammation (hives, eczema)
• Swollen facial tissue, tongue, or limbs
• Mouth tingles or itches
• Nasal drip or congestion
• Digestive issues (cramps, diarrhea, vomiting)
• Dizziness and lightheadedness
• Anaphylaxis (potentially fatal body system shutdown)

Common substances for IgE testing

There’s crossovers between allergy-causing foods and foods that provoke a degree of sensitivity. However, allergic reactions also include non-food substances—everything from cat hair to dust.

When taking an IgE test, here are the most common allergies that may trigger a reaction [5]:

• Pollen
• Peanuts
• Tree nuts (walnuts, almonds, etc.)
• Shellfish
• Animal dander
• Insect bites or stings
• Dust mites

In general, it’s best to avoid any substance that may have been revealed as triggering your IgE levels, but be sure to talk about this with your healthcare provider. With time and proper health maintenance, you may be able to decrease the severity of your body’s IgE response to a certain substance [6].

If you suspect that certain foods may be contributing to uncomfortable symptoms, it’s important to speak with a healthcare provider. A medical professional can help determine whether your symptoms may be related to a food allergy, food sensitivity, or another underlying condition—and guide you toward the right next steps for testing and treatment.

Everlywell offers several at-home testing options designed to help you better understand your body’s response to certain foods, with sample collection completed from the comfort and convenience of home:

• Food Sensitivity Test and Food Sensitivity Comprehensive Test for food-related IgG testing

Taking a proactive approach to your health can help you make more informed decisions about your diet, symptoms, and overall well-being.