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Understanding Soy Allergies in Babies

January 25, 2022 4 min read

As one of the nine most common food allergies in the United States, a soy allergy starts in infancy and most commonly affects children under 3. While Soybeans may not seem like a food your little one will be munching on, it is a common ingredient in many of their favorite foods and snacks - like infant formula, cereals, and yogurt. 

A Soy allergy not only affects your child's nutritional health but can have rippling effects on their quality of life, from living in fear around food to feeling restricted in their daily activities. 

That’s why at SpoonfulONE we’re on a mission to fight these rising rates. Ready to learn more? Here’s what parents need to know about soy allergies.

How Common Is A Soy Allergy In Babies?

Affected by both genetic and environmental factors, a food allergy occurs when your child's immune system decides that a certain food is a "danger" to their health. Their immune system starts sending out immunoglobulin E (or IgE) antibodies that react to the food and cause an allergic reaction.

According to FARE, around 1.9 million Americans of all ages show symptoms of soy allergies with around .4% being babies. Though .4% may not seem like a lot, if you consider that up to 4 million babies are born in the United States each year, this adds up. 

And every year, food allergy rates are increasing. The CDC reports that the prevalence of food allergies in children has increased by 50% between 1997 and 2011, with as many as 6 million children in the United States developing some form of food allergy. 

What Does A Soy Allergy Look Like?

Common triggers of a soy allergy include soy milk, soy sauce, and other soy products including some infant formulas. 

These reactions can range from mild, like sneezing or itching, to severe, like swelling or anaphylaxis that results in difficulty breathing and a sudden drop in blood pressure that sends the body into shock. 

Most food-related allergy symptoms occur within minutes of eating, but allergic reactions can still occur within 2-4 hours of ingestion. Signs that your baby has developed a soy allergy may include:

  • Stomach distress including vomiting, cramps, indigestion, or diarrhea
  • Difficulty breathing, wheezing, or shortness of breath
  • Repetitive cough, hoarse voice, or tightness in the throat
  • Hives, red skin, or swelling around the face, mouth, or tongue
  • Confusion, dizziness, or loss of consciousness
  • Weak pulse
  • In rare cases, anaphylaxis

If your child has shown a reaction to soy, you should have your pediatrician test for a food allergy. Common testing methods include a skin prick test, IgE testing, and an oral food challenge. 

Long-Lasting Effects Of A Soy Allergy

According to the ACAAI, about 40% of children with a food allergy are allergic to more than one food. Studies have shown that babies with a soy allergy seem to have a higher chance of obtaining other food allergies. In fact, one study found that up to 88% of soy-allergic patients also had a peanut allergy, or were more likely to be sensitive to peanuts.

Some children will also grow out of their allergies. A study showed that approximately 50% of children with soy allergy outgrew their allergy by age 7 years. But there is no guarantee that your child will outgrow their food allergies, and some persist into adulthood and become lifelong.

Lastly, studies have shown that children with a food allergy are two to four times as likely to develop other allergic conditions, such as asthma or eczema.

How To Manage Soy Allergies

If your child is allergic to soy, they will need to avoid all foods from the soybean plant and other soy derivatives, often found in many common foods such as:

  • Infant formulas
  • Soups
  • Canned tuna
  • Processed meats
  • Nut butters
  • Soy milk, yogurt, or ice cream
  • Tofu
  • Vegetable broth
  • Sauces, including soy sauce and teriyaki sauce 
  • Asian cuisine, including Chinese, Indian, Indonesian, Thai, and Vietnamese
  • Foods containing soy protein, flour, curds, or fibers

As one of the nine most common allergens, U.S. federal law requires all packaged food products that contain soy to state that on the ingredient label. However, many food products contain hidden soy, like natural flavorings, candies, margarine, sauces, and cereals. Be sure to closely examine food labels, and when in doubt, stay safe and avoid feeding this food to your child.  

How to Avoid A Soy Allergy in Babies

We know that no parent wants to see their child suffer from food allergies, but unfortunately, there is no guarantee that they can be avoided. 

However, there is still hope. Groundbreaking clinical studies, like LEAP and EAT, have taught us that babies who were given potentially allergenic foods as a regular part of their diet were less likely to develop a food allergy. 

According to the AAP and the USDA’s latest guidelines, you can (and should!) start introducing allergenic foods like soy to your baby alongside other solids. In fact, experts now consider it safe for your child to start allergen introduction as early as four months, rather than later in life. 

At SpoonfulONE, we believe regular, consistent exposure to common allergens in the diet throughout early childhood is key to staying healthy.