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Management of Food Allergies

On this page:Infant feeding problems >
     What to do when you suspect your breastfed child is having
adverse reactions to foods you eat?
Management of food allergy in infants >
     Breastfeeding after an allergy diagnosis
    Breastfeeding mother’s dietary restrictions: maintaining a healthy diet
     Breastfeeding mother’s dietary restrictions: maintaining the necessary
intake of vitamin D and calcium
     Management of food allergy: Commercial formulas and other types of milk
Management of food allergy: Introduction to solid foods >

Infant feeding problems

A food allergy is the body’s adverse response to a protein that is harmless to most people.

When the body’s immune system reacts to certain foods (known as allergens), mistakenly perceiving them as harmful, the body then responds to the perceived threat by producing antibodies. There are two main categories of food allergies: IgE-mediated allergies and non-IgE mediated allergies (also known as type IV allergies).

IgE-mediated allergy

The vast majority of food allergy reactions are characterized by the production of IgE antibodies.

When in contact with an allergen, the immune system triggers the production of chemicals that cause allergy symptoms.

An IgE-mediated allergy is usually diagnosed using medical history, skin testing, blood sampling, and oral food challenges.

Non-IgE-mediated allergy (also known as a type IV allergy)

The prevalence of non-IgE-mediated allergies is increasing.

Unlike IgE-mediated allergies, non-IgE-mediated allergies are not diagnosed using skin or blood tests because they do not involve the production of specific IgE antibodies.

Diagnosis of a non-IgE-mediated allergy is based on a person’s medical history and the health improvements that are observed following exclusion of the suspected food from their diet.


IgE-mediated food allergy

  • Involves the immune system
  • A reaction can be triggered by the ingestion of a very small amount of the food, or by simple contact with it
  • Rapid onset of symptoms (often within minutes)
  • May cause very severe and life-threatening reactions
  • Positive skin tests and the presence of specific IgE antibodies
  • Signs and symptoms can affect different systems (digestive, respiratory, cardiovascular as well as cutaneous systems).

Non-IgE-mediated food allergy

  • Involves the immune system
  • The intensity of the reaction is usually proportional to the amount of food ingested
  • Slower onset of symptoms (it often takes several hours or even days)
  • Moderate to severe reactions
  • Negative skin tests and the absence of specific IgE antibodies
  • Affects the digestive system: vomiting, variation in stool frequency, abdominal pain, mucus or blood in the stool

What to do when you suspect your breastfed child is having adverse reactions to foods you eat?

Some children show allergy symptoms when proteins consumed by their mother are excreted into the breastmilk. The child’s body reacts to these proteins, which it perceives as foreign. Excluding specific foods from their mother’s diet could be recommended by a medical professional in order to resolve symptoms and ensure that breastfeeding can continue.

Here is a list of the most common food allergy symptoms in infants: excessive crying, projectile vomiting, mucus or blood in the stool, feeding aversions or refusal, ongoing / unresolved discomfort.

Other symptoms may include: diarrhea, persistent constipation, black stool, skin problems such as eczema, hives, or swollen red patches, asthma, difficulty breathing, swelling of the lips, tongue, and throat, poor weight gain, anemia, difficulty sleeping, irritability, and rapid change in the child’s general condition.

All children may show some of these symptoms at some point, but they will be persistent for children with allergies.

In young children, the most common allergens are:

  • Dairy products (milk, yogurt, cheese, ice cream, etc.)
  • Eggs
  • Peanuts
  • Tree nuts
  • Wheat
  • Soy
  • Fish, molluscs and crustaceans

If an infant is allergic to the proteins of a particular food that is transferred to the child through breast milk, they will usually feel better in the days following the exclusion of that food from the mother’s diet. If the food is reintegrated into the mother’s diet, symptoms will reappear quickly.

Steps to follow when an allergic reaction is suspected in a breastfed child:

  • Stop consuming the food suspected of causing the reaction for 7 days.*
  • Make note of any changes in the baby’s condition or behaviour.
  • If no improvement is noted after the removal of the suspected food, the child’s discomfort may be related to the consumption of another food or the child may have an entirely different health problem.

*It should be noted that when the mother stops consuming the suspected food, changes in the child’s condition may vary from one child to another.

At this stage, it is important to consult a health professional to avoid unnecessary exclusion of foods from the mother’s diet and to more accurately determine the cause of the child’s symptoms. This consultation is essential and will help avoid self-diagnosis, which can sometimes lead to other problems. Consult the Association of Allergists and Immunologists of Québec’s website for a list of allergists (listed by region) and the OPDQ website (in French) for a list of nutritionists (listed also by region). Note that to consult an allergist, you must first obtain a referral from your general practitioner.


IgE-mediated allergy

An IgE-mediated allergy is usually diagnosed using the patient’s medical history, skin testing, blood sampling, and an oral food challenge.

The Skin Prick Test

An allergen concentrate or a sample of the food is placed on the patient’s arm and a slight prick is made. The health professional then waits 15 minutes for a reaction on the patient’s skin, which is measured in millimeters or centimeters.

Blood Testing

A blood test is performed to determine which foods cause the body to produce antibodies.

The Oral Food Challenge

This test is usually used to confirm a diagnosis or check if an allergy has disappeared. It is also sometimes used to assess tolerance to certain forms of an allergen (such as eggs and milk). Food is ingested by the patient under medical supervision.

Non-IgE-mediated allergy

Since skin and blood tests do not allow the diagnosis of this type of allergy, the exclusion of the food from the patient’s diet is recommended. An oral food challenge is sometimes used to confirm the diagnosis.

Management of food allergy in infants

What to do if you are breastfeeding and your child’s allergy is confirmed
When a food allergy diagnosis is made by a health professional, the doctor may suggest that the mother remove the suspected food from her diet, even if consumed only in trace amounts. However, not all women excrete proteins in their breastmilk the same way. Indeed, in cases where the baby has no symptoms, the mother can continue to eat the allergen.

In some cases, the child will outgrow the allergy, sometimes as early as one or two years of age. About 75% of allergies to milk, eggs, soy, and wheat are resolved before the age of 8.

Dietary restrictions for breastfeeding mothers: maintaining a healthy diet
Whether their child is allergic or not, breastfeeding mothers’ dietary goals are the same: to maintain a diet that promotes optimal health and adequate nutrient intake.

Depending on the number of allergens to be avoided, a restricted diet can have an impact on the mother’s health.

The processes of ensuring that breastmilk does not contain antigens can require a lot of effort and planning. Therefor dietary restrictions are not recommended if the child is asymptomatic.

Dietary restrictions for breastfeeding mothers: maintaining the necessary intake of vitamin D and calcium
While sometimes necessary when an infant has a milk allergy, the elimination of dairy products from a breastfeeding mother’s diet often results in a decrease in calcium intake. To ensure that the mother’s needs are met, it is important to include substitutes in her diet.

For breastfeeding mothers, the recommended nutrient intake for calcium varies with age. Since the recommended nutrient intake for vitamin D can be difficult to meet without dairy products, a supplement is often recommended (600 IU per day).

Recommended nutrient intake of calcium for breastfeeding mothers:

  • Under 18 years of age: 1,300 mg per day
  • 18 years and over: 1,000 mg per day

Recommended vitamin D intake for breastfeeding mothers:

  • 600 IU per day

If no soy allergy is suspected, tofu and other soy-based foods are rich in calcium and make for a great substitute.

Here are some other calcium-rich foods that do not contain milk or soy protein:

  • Black beans, lima beans, lentils, chickpeas, red, pinto and romano beans, white beans
  • Some green vegetables: broccoli and Chinese broccoli, mustard leaves, cabbage, bok choy, green cabbage, rapini (broccoli rabe), okra
  • Hummus
  • Oranges
  • Almonds
  • Some bread (check the Nutrition Facts label for the amount of calcium and read the Ingredients List to make sure there aren’t any milk-based ingredients)
  • Canned fish with bones: salmon, sardines
  • Calcium-enriched rice and almond drinks

Food allergy management: Commercial infant formulas and other types of milk

Commercial infant formulas

Most commercial infant formulas can be problematic for young children with milk allergies. These children will generally tolerate highly hydrolyzed infant formulas.

Here is a list of different brands of commercial formula (in French) that should be discussed with your healthcare professional, based on your child’s needs.

For more severe cases, or when highly hydrolyzed formulas are not tolerated, amino acid-based formulas are recommended.

Most provincial insurance plans reimburse the cost of highly hydrolyzed and amino acid-based infant formulas when medically prescribed.

Other types of milk

Being able to replace cow’s milk with the milk from other animals (such as goats, sheep, and mares) is rare, since they all contain very similar proteins. Therefore those allergic to cow’s milk will also likely be allergic to these other types of milk.

Food allergy management: Introducing solid foods

From the sixth to the twelfth month

It is recommended to introduce solid foods at around six months of age but not before four months, starting with iron-rich foods.

When a food allergy diagnosis is confirmed, the child should avoid consuming the food in question, even in trace amounts.

Introduce a new food every three days in order to properly observe the child’s reactions. While some reactions are immediate, others may appear a little later.

Special attention should be paid to foods that may trigger cross-reactivity. However, this does not mean completely removing them from the child’s diet. Consult a health professional to assess the risk of cross-reactivity.

A cross-reactivity occurs when a person who is allergic to one substance reacts to another substance that contains similar proteins, even if the two substances or foods don’t seem to have anything in common.

Medical and nutritional monitoring can help children who are living with allergies to avoid nutritional deficiencies that could otherwise hinder their growth.

Allergy type symptoms may also be a sign of another serious medical conditions. It is therefore important to rely on the advice of a health professional when making a diagnosis.