A food allergy is an abnormal response of the body to a certain food. It’s important to know that this is different than a food intolerance, which does not affect the immune system, although some of the same symptoms may be present. Research has found a strong association between food allergies and depression.

When it comes to the topic of food allergies, we often think of young children and egg, milk or peanut allergies. Nearly 5% of children under the age of five years have food allergies and around 11% of adults have them. In total, more than 26 million adults have food allergies.

There are around 170 foods have been reported to cause allergic reactions. Approximately 90% of all food allergies are caused by the following eight foods:

  • Hen’s eggs
  • Fish
  • Cow’s milk
  • Peanuts
  • Shellfish
  • Soy
  • Tree nuts
  • Wheat

For most adults, these are foods we can eat frequently. For someone with an allergy, the reactions to eating these foods can be severe. Allergic symptoms may begin within minutes to an hour after ingestion. The following are the most common symptoms of a food allergy:

  • Cramps
  • Diarrhea
  • Difficulty breathing
  • Eczema
  • Hives
  • Itching or swelling of the lips, tongue, or mouth
  • Itching or tightness in the throat
  • Lowered blood pressure
  • Swelling
  • Vomiting
  • Wheezing

While the context here is how food allergies can affect depression, it’s important to note that food allergy reactions are serious and can be life-threatening. As a matter of fact, every three minutes, a food allergy reaction sends someone to the emergency room and over 200,000 people require emergency medical care for allergic reactions each year in the U.S. alone.

The Four Different Types of Food Allergies

There are four different types of food allergies; 1) IgE or Type 1, 2) IgG or Type 3, 3) IgM, and 4) IgA. Each type can have an effect on the digestive system and, in turn, mental health. Type 1 (IgE) allergies are the type of food allergies that get the most attention. Occurring in roughly 2 to 5% of the population, these are the allergies that come on suddenly.

Type 3 (IgG) allergies can show reactive effects up to several days later, so often the connection between an ailment and the foods eaten isn’t even made by the sufferer or by medical practitioners with whom they consult. It’s estimated that 45 to 60% of people suffer from Type 3 food allergies, many of them never being aware of it.

Type 3 delayed type hypersensitivity responses have been associated with over 100 different allergic symptoms and 150 different medical diseases. The mental health issues associated with delayed food allergies include ADHD, autism, anxiety, and depression.

Research has shown a link between stress, inflammation and poor health. When someone eats as a response to stress, the chances of developing inflammation and a food allergy increases, impacting mental and physical health.

It can be confusing trying to understand the difference between the terms food allergy, food intolerance and food sensitivity. Food allergies happen when the immune system reacts to a substance, which is usually a protein, in a food or group of foods. Typically, the immune system goes into high gear when it detects a harmful substance. It does that by making antibodies. When someone has a food allergy, their immune system identifies a specific protein as harmful and makes antibodies to fight it off. This results in a range of symptoms, including skin rashes, breathing problems and depression.

Food allergies can impact nutrient assimilation, digestion, and the effectiveness of prescription drugs. Additionally, antidepressant drug intolerance may indicate food intolerance. Evidence suggests that people with depression who do not respond to conventional or natural approaches should consult a health professional to determine possible food allergies or food sensitivities.

If you’re considering getting a blood test to see if you have a food sensitivity don’t be surprised if your insurance company won’t pay for it. That’s largely because it’s not considered a medical test. Food sensitivity is not an official medical diagnosis.

There’s no medication to prevent food allergies. The goal of treatment is to avoid the foods that cause the symptoms. After determining what foods you’re allergic to, it’s important to avoid those foods and other similar foods in that food group.

Randi Fredricks, Ph.D.


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