Does Eating Lots of Eggs and Peanuts While Pregnant or Breastfeeding Protect Your Baby From Food Allergy?

What a large Australian study of more than 2,000 families (Palmer and colleagues, New England Journal of Medicine, 2026) found, and what it means for your diet and your baby's first foods

Many parents-to-be with allergies in the family wonder whether eating more egg and peanut while pregnant and breastfeeding could protect their baby. A large Australian study of 2,137 pregnant women found that babies whose mothers ate lots of these foods were about as likely to have egg or peanut allergy at age one as babies whose mothers ate smaller amounts: about 8 in every 100 in both groups. Both diets were safe.

If you or your partner live with asthma, eczema, hay fever or a food allergy, you may already be thinking about whether your baby will have allergies too. It is natural to look for something you can do, and food is often the first thing parents think of. This article explains what the new research, published by Palmer and colleagues in 2026, tested [1], what it found, and what it means for the choices you make for yourself and your baby.

Why families wonder whether a mother's food matters

A food allergy happens when the body's defence system, the immune system, mistakes a harmless food for a threat. In the kind of allergy studied here, called IgE-mediated allergy (IgE is a type of antibody, a protein the immune system makes), the body reacts soon after the food is eaten; the most serious kind of reaction is called anaphylaxis. Egg allergy is among the most common food allergies in babies [2], and peanut allergy is another that worries many parents.

Scientists have known for some time that a baby meets tiny amounts of the foods its mother eats long before it eats them itself. Tiny amounts of whole food proteins have been found in the fluid that surrounds a baby in the womb [3]. Peanut proteins appear in breast milk within minutes of a mother eating peanuts, and in experiments with mice, this milk helped the young animals' bodies learn to accept peanut rather than react to it [4]. Women who ate more eggs had more egg protein in their breast milk [5], and in a large American study, children of non-allergic mothers who ate more nuts around pregnancy had fewer nut allergies [6]. All of this raised a hopeful idea: perhaps a mother could help "train" her baby's immune system by eating more of these foods.

How advice about allergies and food has changed

Not long ago, families at high risk of allergy were often told to avoid or delay foods like egg and peanut, and some mothers cut these foods from their own diets during pregnancy and breastfeeding. A large review of many studies found no sign that mothers avoiding these foods lowered their children's risk of allergy [7]. Then studies in babies turned the old advice upside down. In a landmark trial in the United Kingdom called LEAP (testing early peanut for babies at high risk), babies who regularly ate peanut from infancy were far less likely to be peanut-allergic by age five than babies who avoided it [8]. Another UK trial, called EAT (testing early introduction of several allergy-causing foods in breastfed babies), suggested that babies who ate enough peanut and egg each week had fewer allergies to them [9]. Australian experts updated their advice in 2016 to recommend giving peanut and egg to all babies in their first year [10].

But some babies seemed to be on the road to allergy even before they started solid food. In an earlier study by the same Australian team, more than a third of babies with bad eczema already showed signs of egg sensitivity at 4 months old, before they had knowingly eaten egg [11]. That is why researchers wondered whether the answer might lie even earlier, in pregnancy and breastfeeding, and they set out a careful plan to test it [12].

What the researchers did

The study, called the PrEggNut Study (a trial of a diet rich in eggs and peanuts during pregnancy and breastfeeding), took place in four Australian cities: Perth, Adelaide, Melbourne and Sydney [1]. It included 2,137 pregnant women who were less than 23 weeks pregnant, planned to breastfeed for at least 4 months, and were not allergic to egg or peanut themselves. Each baby had at least two close family members (mother, father, brothers or sisters) with a doctor-diagnosed allergic condition, which earlier Australian research had shown signals a higher chance of food allergy than having just one allergic relative [13].

A computer decided by chance which diet each woman followed, a method called randomisation that makes the comparison fair. One group was asked to eat at least 6 eggs and 60 peanuts every week. The other group was asked to eat no more than 3 eggs and 30 peanuts a week, close to what Australian women usually eat. Eggs and peanuts could be eaten in any form, such as quiche or peanut butter. The diets continued from mid-pregnancy until the baby was 4 months old, and mothers answered a short text-message survey each month about what they ate. Afterwards, every family received the national advice on introducing solid foods and learned how to spot an allergic reaction.

When the babies were about one year old, they visited a major children's hospital in their city for a skin prick test, a quick test where a tiny drop of food extract is placed on the skin. Babies who reacted were offered a carefully supervised feeding test in hospital to see whether they were truly allergic, unless they had already had a clear allergic reaction to the food (or, for some, were already eating it regularly at home).

What the study found

Egg or peanut allergy was found in 7.8% of babies in the high egg-and-peanut group and 8.4% of babies in the standard group [1]. Put another way, about 8 in every 100 babies had one of these allergies, whichever diet their mother followed. The small difference could easily have happened by chance. Egg allergy alone affected about 6 to 7 in 100 babies in each group, and peanut allergy about 3 in 100 in both. Eczema, an itchy skin condition, was common, diagnosed in roughly 43 to 46 in every 100 babies by their first birthday, and similar in both groups.

Importantly, the higher diet was safe. Serious health problems in mothers or babies occurred in about 4 in every 100 families in both groups, and allergic emergencies to egg or peanut in babies were rare in both, under 1 in 100.

How sure can we be about these results?

This was a large, well-run study, and the people who examined the babies did not know which diet the mother had followed, which helps keep the results fair. There are still some limits worth knowing. Fewer babies developed allergies than the researchers expected (about 8 in 100 rather than 16 in 100), which made it harder to spot a small benefit, and the researchers say a meaningful benefit, as large as about a 30% lower risk, cannot be ruled out. One likely reason allergies were less common is good news: since Australian advice changed, families have been introducing egg and peanut earlier, and allergy rates have fallen. In another Australian study by some of the same researchers, families who were given the updated advice had far fewer egg, peanut and cow's milk allergies in their babies [14], and in Melbourne, egg allergy became less common as babies started egg earlier [2].

Sticking to the high diet was also harder for some women: about two in three met the egg and peanut targets in at least three out of every four monthly surveys, compared with roughly three to four in five women keeping within the limits in the standard group. And the study included mainly mothers from families with lots of allergies, who were not allergic to egg or peanut themselves, and followed babies only to their first birthday.

What this means for you and your baby

The message is reassuring and simple. You do not need to avoid eggs or peanuts while pregnant or breastfeeding, and you do not need to eat extra in the hope of preventing allergy. If you enjoy these foods, you can keep eating them as part of your normal diet. The latest Australian advice encourages breastfeeding with no special changes to the mother's diet for allergy prevention [15].

The step that does make a difference comes later, with your baby's own food. Current advice is to start solid foods when your baby shows signs of being ready, usually around 6 months and not before 4 months, to give well-cooked egg and an appropriate form of peanut soon after (your child health nurse or doctor can explain which forms suit babies), and then to keep offering them about once a week [15]. If your baby was born early or spent time in a neonatal unit, ask your care team about the best timing for solids; In[Neo]Sight has a separate article on starting solids after preterm birth. And if your baby does develop an allergy, this study gives no reason to blame what you ate.

What researchers are working on next

Scientists still want to know whether a mother's diet changes how a baby's immune system responds to food, and the PrEggNut team planned blood tests in some families to look at this [12]. Future studies may follow children for longer, include more families from different backgrounds, and focus on babies at the very highest risk. For now, as the study authors concluded, eating large amounts of egg and peanut in pregnancy and breastfeeding "did not result in a significantly lower risk" of egg or peanut allergy by age one [1]. The best thing families can do is enjoy a normal, varied diet and introduce egg and peanut to their baby on time.

References

  1. Palmer DJ, Campbell DE, Nanan R, et al. Trial of a Maternal Diet Rich in Eggs and Peanuts to Reduce Infant Allergy. N Engl J Med. 2026;395(11):1090-1099. doi:10.1056/NEJMoa2605659 ↩
  2. Koplin JJ, Shifti DM, Soriano VX, et al. Egg Allergy Prevalence Before and After Guidelines for Earlier Egg Introduction. JAMA Pediatr. 2026;180(9):1015-1023. doi:10.1001/jamapediatrics.2026.2080 ↩
  3. Pastor-Vargas C, Maroto AS, Díaz-Perales A, et al. Detection of major food allergens in amniotic fluid: initial allergenic encounter during pregnancy. Pediatr Allergy Immunol. 2016;27(7):716-720. doi:10.1111/pai.12608 ↩
  4. Bernard H, Ah-Leung S, Drumare MF, et al. Peanut allergens are rapidly transferred in human breast milk and can prevent sensitization in mice. Allergy. 2014;69(7):888-897. doi:10.1111/all.12411 ↩
  5. Metcalfe JR, Marsh JA, D'Vaz N, et al. Effects of maternal dietary egg intake during early lactation on human milk ovalbumin concentration: a randomized controlled trial. Clin Exp Allergy. 2016;46(12):1605-1613. doi:10.1111/cea.12806 ↩
  6. Frazier AL, Camargo CA Jr, Malspeis S, Willett WC, Young MC. Prospective study of peripregnancy consumption of peanuts or tree nuts by mothers and the risk of peanut or tree nut allergy in their offspring. JAMA Pediatr. 2014;168(2):156-162. doi:10.1001/jamapediatrics.2013.4139 ↩
  7. Garcia-Larsen V, Ierodiakonou D, Jarrold K, et al. Diet during pregnancy and infancy and risk of allergic or autoimmune disease: A systematic review and meta-analysis. PLoS Med. 2018;15(2):e1002507. doi:10.1371/journal.pmed.1002507 ↩
  8. Du Toit G, Roberts G, Sayre PH, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015;372(9):803-813. doi:10.1056/NEJMoa1414850 ↩
  9. Perkin MR, Logan K, Tseng A, et al. Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants. N Engl J Med. 2016;374(18):1733-1743. doi:10.1056/NEJMoa1514210 ↩
  10. Joshi PA, Smith J, Vale S, Campbell DE. The Australasian Society of Clinical Immunology and Allergy infant feeding for allergy prevention guidelines. Med J Aust. 2019;210(2):89-93. doi:10.5694/mja2.12102 ↩
  11. Palmer DJ, Metcalfe J, Makrides M, et al. Early regular egg exposure in infants with eczema: A randomized controlled trial. J Allergy Clin Immunol. 2013;132(2):387-92.e1. doi:10.1016/j.jaci.2013.05.002 ↩
  12. Palmer DJ, Sullivan TR, Campbell DE, et al. PrEggNut Study: protocol for a randomised controlled trial investigating the effect of a maternal diet rich in eggs and peanuts from <23 weeks' gestation during pregnancy to 4 months' lactation on infant IgE-mediated egg and peanut allergy outcomes. BMJ Open. 2022;12(6):e056925. doi:10.1136/bmjopen-2021-056925 ↩
  13. Koplin JJ, Allen KJ, Gurrin LC, et al. The impact of family history of allergy on risk of food allergy: a population-based study of infants. Int J Environ Res Public Health. 2013;10(11):5364-5377. doi:10.3390/ijerph10115364 ↩
  14. Walker SVM, D'Vaz N, Pretorius RA, et al. Infant Diet Recommendations Reduce IgE-Mediated Egg, Peanut, and Cow's Milk Allergies. J Allergy Clin Immunol Pract. 2025;13(11):3077-3083.e1. doi:10.1016/j.jaip.2025.06.012 ↩
  15. Vale SL, Netting MJ, Hornung CJ, et al. ASCIA Guideline: Infant Feeding for Food Allergy Prevention. Clin Exp Allergy. 2026;56(4):319-329. doi:10.1111/cea.70217 ↩