Food Allergies And Intolerances

Jeannette | Posted on November 10, 2021 
most common food intolerances

What is a food allergy?

A food allergy is linked to the body’s immune system, as it reacts to certain proteins in the food. The reaction occurs when the immune system identifies the protein in food as harmful and triggers a protective response against it. These types of allergies are called immunoglobulin E (IgE) mediated food allergies. According to the Centers for Disease Control and Prevention, food allergies affect approximately 4-6% of children and around 4% of adults.

What is a food intolerance?

Often confused with, or mislabeled as food allergies, food intolerances mainly involve the digestive system. Not all of them result in anaphylaxis, hence are rarely life-threatening, if treated properly and on time. Food intolerance is difficulty in digesting certain foods and having an unpleasant physical reaction to them, such as bloating or stomach pain. Statistically speaking, they affect 15-20% of the population, and according to the IBS Network; people with IBS are more likely to have food intolerances.

Symptoms of allergic reaction

The symptoms of allergic reactions could vary in severity, from mild symptoms such as swollen lips to severe to life-threatening conditions. The severe symptoms include anaphylaxis, which may involve severe respiratory problems and impaired breathing. Anaphylaxis can occur within minutes of exposure to certain allergens in food, causing a dramatic drop in your blood pressure and thereby, affecting the heart rate.


Furthermore, just because an initial reaction to one of the most common food sensitivities causes fewer problems now does not mean that the subsequent reactions won’t be adverse. Since certain foods that previously triggered mild symptoms could cause more severe symptoms later on. Below are some of the most common allergy or food sensitivity symptoms.

  • Anaphylaxis
  • Abdominal cramps
  • Coughing or Wheezing
  • Difficulty breathing
  • Dizziness and/or lightheadedness
  • Flushed skin or rash
  • Hives
  • Loss of consciousness
  • Swelling of face, lips, or tongue
  • Swelling of the throat and vocal cords
  • Tingling or itching sensation in the mouth
  • Trouble swallowing
  • Vomiting and/or diarrhea

Unlike anaphylaxis, most food-related symptoms occur within two hours of ingestion. Rarely, in some cases, the reaction may be delayed by four to six hours or longer. The longer onset of allergic symptoms occurs most typically in people who suffer from eczema, which develops as a symptom of food allergy.

Symptoms of food intolerance

In people with food intolerance, the severity of their symptoms is determined by the amount of problem food that the person eats. Unlike most cases of food allergies, the symptoms of food intolerances can take a while to emerge. The onset tends to occur several hours after ingesting a food, and the symptoms may persist for several hours or days.

  • Headaches or Migraines
  • Hives (urticarial)
  • Irritable Bowel Syndrome (IBS)
  • Malaise (a general feeling of being under the weather)
  • Rashes
  • Recurrent mouth ulcers

How do you know if you have a food allergy or food intolerance?

Since the signs and symptoms of most common food intolerances and food allergies are usually overlapping, it is quite difficult to determine which condition a person has. While the smallest amount of food can trigger food allergies, people with food intolerance may not develop symptoms unless they eat large portions of the certain food that does not suit them.

For example, people with a peanut allergy start developing severe symptoms of anaphylaxis at the smallest amount ingested, whereas a person who is lactose intolerant may be able to drink milk in coffee and only start showing symptoms upon consuming more than one glass of milk. Similarly, food allergies occur each time a person ingests the particular allergen present in the food. This is not usually the case with food intolerances, as the symptoms are related to the dosage of a certain food intake.

7 most common food allergens and intolerances

  • Gluten

In patients with celiac disease, consumption of gluten triggers an immune response in the small intestine, damaging the intestinal lining and resulting in malabsorption of nutrients. This damage can cause anemia, bloating, diarrhea, fatigue, weight loss, and other serious complications. While celiac disease has no cure, a strict gluten-free diet can help manage symptoms and prevent emergencies.

  • Milk

Mostly referred to as lactose intolerance, this is one of the most common food intolerances in which the patient is unable to fully digest the lactose sugar present in milk. As a result, they experience diarrhea, gas, and bloating after eating or drinking dairy products. While this condition is usually harmless, the symptoms are often very uncomfortable.

  • Tree Nuts

Found in both adults and children, allergy to tree nuts can show up in either mild or life-threatening symptoms. Being allergic to one tree nut does not usually mean that you are allergic to all of them. The most common tree nut allergy in the US is cashew, while that in the UK is hazelnut.

  • Eggs

Most commonly causing allergies in children, their symptoms tend to occur a few minutes to a few hours after eating eggs or foods containing eggs. Egg allergies show mild to severe symptoms, ranging from skin rashes and hives to nasal congestion, and digestive problems. Aside from allergies, egg intolerance also persists in children, leading to abdominal pain or bloating, cramps, diarrhea, nausea, and/or vomiting.

  • Peanuts

Peanut allergies develop after primary exposure to the allergen. This is one of the most dangerous allergies as the allergic response usually occurs within minutes after exposure, leading to symptoms such as itching around the mouth and throat, digestive problems, and in worst cases, anaphylaxis.

  • Fish

Similar to other allergies, fish allergies range from mild, such as hives and cramps, to severe symptoms, such as wheezing, diarrhea, and vomiting. Common fish types that are known to cause allergies are salmon, tuna, and halibut.

  • Sesame

Food intolerance doctors recommend that patients carry an epinephrine injection with them at all times. This is to counter a potential anaphylaxis reaction due to sesame consumption. Other symptoms could include hives, redness, and swelling in the face, hoarse voice, etc.

See Also: Banana Allergy: Symptoms and Risk Factors


While the development of promising strategies and therapeutic prevention is underway, food allergies and sensitivities do not have a cure as yet. To prevent serious health consequences, owing to the most common food intolerances or allergies, early recognition and management of food allergies are essential.

It is important to always consult a doctor if you experience an onset of allergic or intolerance symptoms after a particular meal that could hold any of the above-mentioned most common food intolerances. In most cases, doctors and dieticians suggest avoiding or at least reducing the intake of the problem food. However, if you do consume foods that don’t suit you and experience symptoms such as heartburn or stomachache, an antacid medication is mainly prescribed.

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