Babies who received formula within 24 hours of birth were 3.6 times more likely to develop egg allergy by age one, according to a 2026 cohort study of 563 high-risk infants. The research suggests that colostrum, the nutrient-rich fluid mothers produce before milk, helps protect developing immune systems during a critical window. Avoiding formula in the first day of life, combined with introducing eggs at six months, may help prevent egg allergies in babies with a family history of allergies.
A new study of 563 babies found that infants who received commercial formula within the first 24 hours of life were more than three times more likely to develop an egg allergy by age one. The research suggests that early colostrum, the nutrient-rich fluid mothers produce before breast milk, helps protect babies’ developing immune systems. According to Gram Research analysis, avoiding formula supplementation in the first day of life, combined with introducing eggs at six months, may help prevent egg allergies in babies with a family history of allergies.
Key Statistics
A 2026 cohort study of 563 infants with family histories of allergies found that babies receiving formula within 24 hours of birth had a 3.62 times higher risk of developing egg allergy by age one year.
Among 563 high-risk infants in a 2026 study, 21.8 percent received formula within the first 24 hours of life, and these babies showed 2.5 times higher odds of egg sensitization by age one.
In a 2026 prospective cohort study of 563 newborns, 3.4 percent developed egg allergy despite timely egg introduction at six months, with early formula use significantly increasing this risk.
The Quick Take
- What they studied: Whether giving babies formula in their first few days of life increases the risk of developing an egg allergy
- Who participated: 563 newborns born at 37 weeks or later, all with a family history of allergies, followed from birth to age one year
- Key finding: Babies who received formula within 24 hours of birth were 3.6 times more likely to develop egg allergy by age one, and 2.5 times more likely to show signs of egg sensitivity
- What it means for you: If you have a family history of allergies, delaying formula and prioritizing colostrum in the first day may help reduce egg allergy risk. However, this finding is specific to egg allergy and needs confirmation in larger studies before becoming standard medical advice
The Research Details
Researchers followed 563 babies from birth to one year old. All the babies had at least one family member with allergies, making them higher risk for developing allergies themselves. The researchers carefully tracked what each baby ate in the first three days of life, noting whether they received breast milk, colostrum, formula, or a combination. At one year old, doctors tested each baby for signs of egg allergy and egg sensitivity using blood tests that measure immune response.
This type of study is called a cohort study because researchers follow a group of people over time and observe what happens naturally, rather than randomly assigning them to different feeding methods. This approach lets researchers see real-world feeding patterns and their effects, though it cannot prove that formula directly causes allergies.
The first few days after birth are critical for a baby’s immune system development. Colostrum, the thick fluid mothers produce before milk, contains special proteins and immune factors that help babies’ gut bacteria develop properly and teach their immune system how to respond to different foods. When babies receive formula instead, they miss out on these protective factors during this crucial window. Understanding this timing helps doctors and parents make informed feeding decisions.
This study has several strengths: it prospectively collected feeding data (meaning researchers tracked it as it happened, not from memory), it included a reasonable sample size of 563 babies, and it adjusted for other factors that might affect allergy risk. However, the study only included babies with a family history of allergies, so results may not apply to all babies. The study was observational rather than experimental, so it shows association but not definitive cause and effect. The number of egg allergy cases was relatively small (19 babies), which limits how confident we can be in the findings
What the Results Show
Among the 563 babies studied, 36.8 percent received some formula in their first three days of life. Of those, 21.8 percent received formula within the first 24 hours. By age one year, 3.4 percent of all babies in the study had developed an egg allergy.
Babies who received formula within 24 hours of birth had significantly higher egg allergy risk. The adjusted odds ratio was 3.62, meaning these babies were approximately 3.6 times more likely to develop egg allergy compared to babies who did not receive early formula. This difference was statistically significant, meaning it’s unlikely to have occurred by chance.
The same pattern appeared for egg sensitization, a sign that the immune system is reacting to egg protein even if full allergy symptoms haven’t developed yet. Babies receiving early formula had 2.5 times higher odds of egg sensitization. Importantly, all babies in the study were introduced to eggs at six months of age, following current allergy prevention guidelines.
The study found no increased risk for other food allergies or sensitization in babies who received early formula. However, the researchers note this finding is limited because there were very few cases of other food allergies in the study group. The study also measured eczema, a skin condition often associated with allergies, but found no significant association with early formula use. This suggests the early formula effect may be specific to egg allergy rather than a general increase in all allergic conditions.
Previous research has shown that early formula use is associated with increased food allergy risk in general. This study adds important specificity by identifying egg allergy as particularly vulnerable to early formula introduction. The finding aligns with biological understanding that colostrum provides immune protection during a critical developmental window. However, most previous studies have not examined the specific 24-hour window, making this timing detail a new contribution to the field.
The study only included babies with a family history of allergies, so results may not apply to babies without allergic relatives. The number of babies who developed egg allergy was relatively small (19 babies), which limits statistical power. The study observed natural feeding patterns rather than randomly assigning babies to different feeding methods, so other unmeasured factors could explain the association. The study was conducted in a specific population and may not represent all demographic groups. Researchers could not determine whether the effect comes from missing colostrum, the formula itself, or both
The Bottom Line
For babies with a family history of allergies, delaying formula introduction and prioritizing colostrum in the first 24 hours may help reduce egg allergy risk. This recommendation has moderate confidence based on this single cohort study and should be discussed with your pediatrician. Combined with introducing eggs at six months of age (as recommended by allergy prevention guidelines), this approach appears to offer additional protection. Parents should not feel guilty if early formula use was necessary for their baby’s health and nutrition.
This finding is most relevant for families with a history of allergies, particularly egg allergy. Parents planning to breastfeed should discuss colostrum and early feeding with their healthcare provider. Healthcare providers caring for high-risk infants should consider this information when counseling families about early feeding. Babies without a family history of allergies may have different risk profiles and should follow their pediatrician’s recommendations. Babies who cannot breastfeed should receive formula as needed without guilt, as nutrition and growth are paramount.
Egg allergy typically develops within the first year of life. In this study, allergy assessment occurred at age one year. Benefits of avoiding early formula would theoretically appear by this age, though individual variation is expected. Some babies may show signs of egg sensitivity earlier, while others may develop allergy later. Ongoing monitoring through age three is recommended for high-risk children, as some allergies resolve naturally over time
Frequently Asked Questions
Does giving a newborn formula in the first day increase allergy risk?
For babies with a family history of allergies, receiving formula within 24 hours of birth increased egg allergy risk 3.6 times by age one in a 2026 study of 563 infants. Babies without allergic relatives may have different risk profiles.
Why is colostrum important for preventing allergies?
Colostrum contains immune proteins and beneficial bacteria that help develop a baby’s gut microbiome and teach the immune system how to respond to foods. This protection is most critical in the first 24 hours of life.
Should I avoid formula if I’m breastfeeding?
If you can provide colostrum in the first 24 hours, this may reduce egg allergy risk in high-risk babies. However, formula is essential if breastfeeding isn’t possible. Discuss timing and options with your pediatrician based on your situation.
Does early formula increase risk for all food allergies?
This study found increased risk specifically for egg allergy, not other food allergies. The effect appears targeted to egg rather than a general increase in all allergic conditions, though more research is needed.
At what age should I introduce eggs if my baby is high-risk?
Current guidelines recommend introducing eggs at six months of age, even for high-risk babies. Combined with avoiding early formula when possible, this timing may help reduce egg allergy development.
Want to Apply This Research?
- Log infant feeding method and timing in the first 72 hours of life (breast milk, colostrum, formula, or combination), then track any signs of egg sensitivity or allergy at six months and one year of age
- If planning to breastfeed, discuss colostrum collection and early feeding timing with your healthcare provider before delivery. If formula supplementation is needed, discuss timing with your pediatrician to minimize early formula use when possible
- Set reminders to document feeding patterns in the first three days postpartum. At six months, note any reactions when eggs are introduced. At one year, record any allergy testing results or symptoms. Track eczema or other allergy signs monthly through age three
This research describes associations between early formula use and egg allergy risk in babies with a family history of allergies. It does not prove that formula causes allergies. Every baby’s feeding situation is unique, and formula is essential nutrition when breastfeeding is not possible or sufficient. Parents should discuss their infant’s feeding plan with their pediatrician, who can provide personalized guidance based on the baby’s individual health needs, family history, and circumstances. This article is for educational purposes and should not replace professional medical advice. If you suspect your baby has an egg allergy, consult your pediatrician or allergist for proper testing and diagnosis.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.