Issue No. 398：A Doctor's Take on Hydrolyzed Formulas—Busting Common Infant Allergy Myths

"Allergies are a common issue in Taiwan, including skin allergies, respiratory allergies, and food allergies. To prevent their children from developing similar symptoms, many parents try to reduce allergens in their environment and diet. Since a baby's primary nutrition comes from milk, many parents who see their infants experiencing digestive issues like diarrhea, vomiting, or bloating after feeding mistakenly believe it's an allergy. This leads them to follow the trend of switching to hydrolyzed formulas, which are advertised as being less allergenic.

However, discomfort after drinking milk isn't always an allergy, and not all infants with digestive issues need a fully hydrolyzed formula. The true key lies in the type and ratio of proteins. In this article, Dr. Hong Yu-chi, a pediatric specialist, helps parents understand common myths about infant milk allergies and choose the right source of nutrition for their children.

Article Contents

Section 1: The Incidence of Infant Cow's Milk Protein Allergy Is Lower Than You Think

Point 1: Only 2-3% of Infants Are Allergic to Cow's Milk Protein, and It Often Improves Naturally with Age

Point 2: Diarrhea, Vomiting, and Indigestion in Infants Aren't Necessarily Due to Cow's Milk Protein Allergy

Section 2: Beta-Lactoglobulin Is a Major Cause of Digestive Issues in Infants

Point 1: Beta-Lactoglobulin Can Be Difficult for Infants to Digest

Point 2: Breast Milk Is Easy to Digest and the Best Source of Nutrition for Infants

Section 3: Complete Proteins with Lower Beta-Lactoglobulin Help Maintain Infant Digestive and Gut Health

Point 1: Formulas with Reduced Beta-Lactoglobulin

Point 2: Complete Proteins Help Train an Infant's Digestive System

Conclusion

Section 1: The Incidence of Infant Cow's Milk Protein Allergy Is Lower Than You Think

Point 1: Only 2-3% of Infants Are Allergic to Cow's Milk Protein, and It Often Improves Naturally with Age

The root cause of food allergies is an overreaction of the immune system to specific proteins. Common food allergens include proteins from milk, eggs, peanuts, soybeans, wheat, tree nuts, and seafood.

Most commercial formulas are cow's milk-based, which can indeed cause cow's milk protein allergy in infants. However, Dr. Hong Yu-chi points out that studies show only about 2-3% of infants truly have an allergic reaction to cow's milk protein. Furthermore, as their digestive systems develop, as many as 85-90% of infants with this allergy naturally develop tolerance and the condition improves on its own by age 3-5 (1, 2).

Point 2: Diarrhea, Vomiting, and Indigestion in Infants Aren't Necessarily Due to Cow's Milk Protein Allergy

According to the latest international guidelines published in 2023, cow's milk protein allergy in infants requires a series of strict diagnostic tests (3). Therefore, symptoms like diarrhea, vomiting, bloating, and other digestive discomforts after feeding do not automatically mean an infant is allergic to cow's milk protein. These symptoms could also be caused by colic, an immature nervous system in the intestinal wall, or lactose intolerance.

For this reason, if your child is experiencing these issues, it's best to consult a pediatrician first and follow their advice on whether to change your baby's milk source. Switching to a hydrolyzed formula without a confirmed cow's milk allergy diagnosis may not provide any real benefit for improving your infant's digestive symptoms.

Section 2: Beta-Lactoglobulin Is a Major Cause of Digestive Issues in Infants

Point 1: Beta-Lactoglobulin Can Be Difficult for Infants to Digest

So why might a newborn infant experience digestive discomfort even without a cow's milk protein allergy? Dr. Hong explains that the main components of cow's milk protein are whey and casein. Whey protein can be further divided into alpha-lactalbumin and the more difficult-to-digest beta-lactoglobulin. Due to its tightly packed structure, beta-lactoglobulin is more resistant to breakdown by digestive enzymes, making it harder to digest.

Point 2: Breast Milk Is Easy to Digest and the Best Source of Nutrition for Infants

Breast milk is the most ideal source of nutrition for infants. The whey protein in breast milk is composed of about 20-30% alpha-lactalbumin, with almost no beta-lactoglobulin. This makes it easy for infants to absorb and digest the proteins in breast milk. In addition to a protein ratio that's easy for babies to digest, breast milk also contains rich immunoglobulins (IgA) and lactoferrin, which help boost a baby's immunity and protect their gut health.

Section 3: Complete Proteins with Lower Beta-Lactoglobulin Help Maintain Infant Digestive and Gut Health

Point 1: Formulas with Reduced Beta-Lactoglobulin

What kind of formula should parents who can't breastfeed choose? Dr. Hong suggests that if you want to reduce the likelihood of your infant experiencing digestive issues from cow's milk, you can choose a formula with reduced beta-lactoglobulin. There are now formulas on the market that use special technology to lower the beta-lactoglobulin content while retaining complete proteins. This addresses the issue of hard-to-digest beta-lactoglobulin while still providing the full nutritional benefits of complete proteins.

Point 2: Complete Proteins Help Train an Infant's Digestive System

The proteins in breast milk are complete proteins, which means infants are naturally able to digest them. Therefore, for infants who have not been diagnosed with an allergy, doctors recommend choosing an infant formula that contains complete proteins to help train the baby's digestive system. This can reduce the likelihood of digestive issues when they consume other dairy products in the future.

Conclusion

Dr. Hong Yu-chi advises that if you notice your infant is uncomfortable after drinking milk, there's no need to panic and immediately assume it's a cow's milk allergy. If you're truly concerned, it's best to consult a professional pediatrician. If a medical-grade hydrolyzed formula isn't necessary, you can choose a formula that preserves complete proteins while reducing the hard-to-digest beta-lactoglobulin. This can help lower the chances of your child's digestive discomfort and help them build a healthy digestive system, ensuring optimal nutrient absorption as they grow.

Health Promotion Section:

Source: Good Eating Class (好食課) https://views.learneating.com/report/newborn-milk-allergy/