Is This a Food Allergy? Or Just an Intolerance?

Food should be enjoyed, so why does eating make your gut miserable at times? And what’s going on in your body that is making you feel this way?

Maybe you have nausea, cramping, stomach pain, or heartburn after you eat certain foods. The trouble is, those can be symptoms of both food intolerance and allergy. So how do you know which one you are struggling with?

Food Allergy

Allergy and intolerance play out in very different ways in the body. Allergy is always a function of the immune system. The immune system is designed to fight off harmful substances, but sometimes, it gets confused and tries to fight off perfectly harmless things. This results in allergy symptoms.

When it comes to food allergies, the body usually overreacts to proteins in certain foods. So let’s say that you eat a peanut. Your body may misconstrue the proteins in that peanut as something harmful like bacteria or a virus. It will then go on the defense and release its ammunition: disease-fighting antibodies (known as immunoglobin E or IgE) and chemicals like histamine.

Your immune system thinks it has done a noble thing, but there was no valid enemy in the first place. Your immune system has needlessly flooded your body with chemicals that cause allergy symptoms.

The “chemical warfare” will affect your body differently depending on where it is released. If it’s released in your nose, you may experience increased mucus production and inflamed nasal passages, resulting in nasal congestion. If it’s released in the digestive tract, you may develop stomach pain and nausea. If it’s released in the skin, you may suddenly find yourself breaking out in hives.

Food Intolerance

Food intolerance has nothing to do with the immune system. Rather, it plays out in your digestive system. Food intolerance occurs when food irritates your digestive system or your body has trouble breaking food down.

It’s estimated that 15-20% of the adult population has food intolerance, compared to about 10% of adults who have food allergies.

Food intolerance and allergy are often confused. Consider a 2019 study in JAMA Network Open showing that while nearly 20% of people report having food allergies, only 10% have symptoms consistent with food allergy.

Whereas allergy is virtually always triggered by your immune system reacting to food proteins, food intolerance can stem from a number of factors. In the case of lactose intolerance, which affects about 1 in 10 Americans, your body lacks the enzymes necessary to break down and digest the lactose in dairy products. With fructose intolerance, your intestines may lack a protein that allows you to absorb fructose from certain fruits and vegetables, leaving you to experience gas, cramps, and bloating.

Food intolerance can also result from your body’s negative reaction to chemicals that are added to foods to improve their appearance, texture, and longevity. These may include artificial colors and flavors, sweeteners, and preservatives.

Nitrates, which lengthen the shelf life of processed meats, are common sources of food intolerance. They can cause headaches and hives. A lot of people also report intolerance to monosodium glutamate (MSG). When they eat foods laced with MSG, they may experience chest tightness, headaches, and nausea.

How Quickly Will my Body React?

If you have a food allergy, reactions usually occur immediately after eating the trigger food, but they can be delayed by a couple of hours. The symptoms of food intolerance will often occur immediately as well, though some may not manifest for 12-24 hours.

Can I Just Eat a Little Without Reacting?

In the case of food intolerance, you may be able to get away with eating small amounts of the trigger food without experiencing a significant reaction. The severity of the food intolerance usually correlates to the amount of food that you eat. For example, if you are lactose intolerant and drink an extra large milkshake, you’ll likely feel much more miserable than you would if you only had a sip of your friend’s shake.

Allergy is different. Even a tiny amount of the allergen can throw you into a tailspin, depending on the severity of your allergy. If you have a bad peanut allergy, for example, you may react severely even if you only breathe in the dust from shelled peanuts or eat something that was made with a little bit of peanut oil.

What are the Symptoms of Food Allergy vs. Intolerance?

What’s the Same?

Both food allergy and intolerance can cause:

• Nausea
• Cramping
• Gas
• Bloating
• Diarrhea
• Heartburn

What’s Different?

Intolerance can cause:

• Irritability/nervousness
• Headaches

Allergy can cause:

• Swelling of the lips, mouth, and throat
• Skin rash
• Nasal congestion
• Swelling of the airways (difficulty breathing)

How Do I Know What Foods are Causing my Reactions?

Sometimes the trigger foods are a smoking gun. You may easily recognize that every time you eat milk or gluten you start to feel bad. But other times, the source may be harder to discover.

You can start by keeping a food diary, recording the foods that you eat and how you feel afterward. You can also try an elimination diet, removing foods from your diet that you suspect may be causing your symptoms and reintroducing them later. If you feel better after eliminating foods and worse after reintroducing them, you’ll be able to identify your triggers.

Make sure to include your doctor in this process so that they can help ensure that you are getting balanced nutrition, even if you have to remove certain foods from your diet permanently.

If you suspect that you have a food allergy, you can talk to your doctor about taking a food allergy test. This can be performed in a number of ways, ranging from skin tests to blood tests. Note, however, that these tests are not foolproof so you may experience false positives or negatives…or both.

Is There a Treatment?

If you are lactose intolerant, you can take a lactase enzyme supplement before eating dairy products. Beyond this, there are few effective treatments to help with food intolerance. Your best bet is to avoid foods that trigger your intolerance. If you do find yourself feeling miserable after eating something, you can manage the symptoms with gas relief pills, antacids for heartburn, etc.

As for food allergy, while avoidance used to be the only option, new treatments are on the horizon. Sublingual immunotherapy offers a food allergy treatment program that treats the source of the food allergy–not just the symptoms. Sublingual immunotherapy for food allergies works similar to allergy shots, exposing your body to traces of allergens so that you can become desensitized to them. This is accomplished through daily oral drops that can be taken at home.