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Breastfeeding and Food Allergies

Contents

Are you worried that your baby:

  • is very uncomfortable, or in pain,
  • is unhappy most of the time, or
  • has other symptoms, such as vomiting, unusual poo, or a rash?
  • Have you been told, or heard, that it could be something you, or they, are eating or drinking?

It’s often suggested that breastfeeding mothers change their diet, to see if it helps their baby. In this article we aim to give you the information you need to decide whether your baby is likely to be reacting to a food, or foods, you (or they) are eating, and if so, what you can do about it.

If you’re feeling worried about your baby, talk to your health visiting team or your doctor.

You might also find it helpful to know we recorded an LLLGB podcast episode with Dr Robert Boyle, a Paediatric Allergy Specialist, that was released on March 20th 2025. This link will take you to the episode on Spotify. Also available on Apple.

My baby is fussy and I don’t know why

Babies can be unsettled for many reasons. With time and effort, it’s sometimes possible to work out the cause, though often we never find out before they grow out of it! If your baby is under two months old and needs lots of calming around the same time each day, this article might be helpful.

You can read more here about the different reasons why babies might be unhappy.

My baby seems more than just fussy

If your baby seems very unhappy or uncomfortable a lot of the time, it’s important to get them checked over by a doctor. You might also want to work with a breastfeeding supporter to see if any adjustments to breastfeeding might help your baby. For example:

  • deeper attachment at the breast can help babies get more milk, more efficiently.
  • offering to nurse more often helps to keep your supply strong and your baby soothed. Carrying your baby (in a sling or carrier) between feeds can also help keep them calm. Always follow safety guidelines when carrying your baby.
  • if you have low milk production, your baby might be unsatisfied after feeds, or need extra milk to grow well. Your breastfeeding supporter can help you increase your supply if possible, or work out the right amount of extra milk, and how to give it.
  • if you have oversupply (more milk than your baby can cope with) and/or a fast flow, there are lots of things you can do to help your baby manage, and to reduce your supply if necessary.

What if none of this helps, and your exclusively breastfed baby is still unsettled, or has other symptoms?

Could it be an allergy to something in my milk?

This is a common suggestion to parents of unsettled babies. However, most unsettled babies are not suffering from food allergies. This may seem at odds with what you have heard, or the impression you have of allergy rates!

It is true that more babies are being referred to allergy clinics – in the UK there was a fourfold increase between 2006 and 2020. (1) However, studies indicate that food allergy rates in young children don’t seem to have increased during this time. (2,3,4,5,6)

Food allergy is more common in some regions of the world than others, with lower rates in rural communities and low income countries. For instance, 1 in 500 children in South India is estimated to be affected by food allergy, whereas in urban communities and high-income countries rates are higher. (7,8) It is estimated that up to 1 in 20 babies and young children in the UK has a food allergy. (9)

Parents of older babies who have started family foods (solids) are often right when they suspect their child has a food allergy. Common food allergens include egg, nuts, milk, fish, shellfish, and sesame. However, cow’s milk allergy (CMPA) in young babies is thought to be significantly overdiagnosed by both parents and doctors. Some reports suggest that nine out of ten babies treated for milk allergy can probably tolerate cow’s milk without an allergic reaction. (10, 11)

What is an allergic reaction?

An allergic reaction is the immune system responding to a specific ‘trigger’. An allergic reaction is always ‘reproducible’ – the food causes similar symptoms every time the child eats or drinks that ingredient, usually within two hours of eating it. Once the trigger is removed, symptoms typically settle down within two or three hours. A medical professional will be able to diagnose an allergic reaction and advise you on the best course of action for that particular allergy. If you think your baby has a food allergy, you might want to speak with your doctor about allergy testing.

Allergic reactions are very rare in babies who are exclusively breastfed (fed only at the breast or with expressed human milk, and haven’t yet started family foods). It has been estimated that if you drink one pint of cow’s milk, your nursing baby would need to consume about 2000 litres of your milk in one feed to ingest enough cow’s milk protein to cause an allergic reaction (12). These tiny amounts of allergenic cow’s milk protein can only be detected in breastmilk for a few hours after you drink cow’s milk. Similar findings have been shown for egg, peanut and wheat. When older babies who have started solids are given cow’s milk directly, it typically takes one teaspoon of milk to cause a reaction. (12) If your baby is having formula as well as breastfeeding, they are much more likely to be reacting to the formula than to your milk.

Types of Food Allergy

There are two types of food allergies – IgE (immediate) and non-IgE (delayed).

IgE (immediate) allergies

Symptoms may include:

  • itchy hives,
  • lip or eye swelling,
  • vomiting,
  • coughing or wheezing,
  • sneezing.

These occur within two hours of consuming a food and, usually, this happens the first time the baby eats the food. Egg and nuts are the most common triggers. Symptoms usually settle completely within two to three hours, and antihistamine medication can help.

IgE allergies happen when food is put directly into the baby’s mouth, where it is quickly absorbed into the body. Usually, food touching skin, or food eaten by a breastfeeding mother, will not trigger an allergic reaction in the baby. However, if the baby has sensitive or broken skin, then a rash or skin swelling could occur with contact.

When a baby has an IgE food allergy, you will need to avoid giving them the food which triggered the reaction. Breastfeeding mothers can usually continue to eat the food allergen without being concerned about harming their baby.

Desensitisation is sometimes used for treating IgE food allergy. This involves giving the baby carefully measured amounts of the food they are allergic to each day, and is usually done under the supervision of a doctor. A medical professional can advise on whether this is appropriate for your baby’s situation.

If you are not sure whether your baby has had an IgE allergy reaction or not, or aren’t sure which food caused a reaction, an allergy skin prick test or blood test can help to make a diagnosis. It might be helpful to know that skin prick tests are good at ruling out an allergy, but less reliable at ruling it in. However, eating the food is the best test, and if done in a carefully controlled and supervised way then the result is most reliable. In practice, it is often not practical to put young children through lots of supervised food challenges, so most food allergy diagnosis is made based on what happened when the food was tried at home, combined with skin prick test or blood IgE results.

Non-IgE (delayed) allergies

Non-IgE allergies are rarer than IgE allergies. There are three types of non-IgE allergies:

  1. The most common is called Food Protein Induced Entercolitis Syndrome (FPIES), which affects about 1 in 200 children in the UK.(13) FPIES causes sudden onset of vomiting and diarrhoea, starting between one and four hours after the baby eats a new food. FPIES is most commonly triggered by cow’s milk, egg, fish, fruit or vegetables, but can be caused by any food. Most babies who have FPIES only react to one food. (14)
  1. A second, rare type of non-IgE allergy is Food Protein Induced Enteropathy. This occurs in babies who are formula fed, and causes diarrhoea, vomiting, and faltering growth.
  1. A third type of non-IgE allergy is proctocolitis. Proctocolitis means inflammation in the lower end of the bowel, close to the anus. Symptoms typically begin around two to four months after birth. Proctocolitis in breastfed babies doesn’t usually indicate a specific food allergy. It gets better on its own by age eight to nine months and does not cause harmful consequences for the baby. There is usually no need for breastfeeding mothers to change their diet when their baby has proctocolitis. Proctocolitis in formula-fed babies sometimes gets better when the formula is changed to a low-allergy formula. However, any trial of low-allergy formula should be carefully considered as it contains high levels of ‘free sugars’. Free sugars have been related to tooth decay and obesity in later life. (15, 16, 17)

The only test to confirm a non-IgE allergy is to exclude the food then reintroduce it, observing how the baby responds.

In some countries, many babies with common symptoms such as:

  • crying,
  • reflux,
  • eczema-like rashes, or
  • poo which seems runny, hard, too frequent, or too infrequent

are misdiagnosed with non-IgE allergy . These are not actually typical symptoms of an allergic reaction. The misconception that these common baby symptoms are signs of milk allergy has been promoted by formula companies over the past 20 years. They benefit from sales of low-allergy formula, and from making breastfeeding difficult by unnecessarily advising mothers to restrict their diet. (18)

Do I need to stop breastfeeding if my baby is allergic?

Sometimes, mothers of allergic babies are recommended to stop breastfeeding and switch to specialist formulas instead. This is usually unnecessary and undermines breastfeeding. Human milk is much healthier than formula for babies, with or without allergies.

Occasionally, an allergic breastfed baby is so unwell that doctors insist on a break from breastfeeding while the mother cuts foods out of her own diet. If you are advised to pause breastfeeding, you can question this advice (19), and express your milk to keep your supply strong.

Eczema

The most common allergy issue in young children is eczema, which causes an itchy rash. Eczema can come and go for months or years. About 1 in 16 children and teenagers worldwide has eczema, but it is most common in babies and preschool children, where up to 1 in 5 are affected in some high income countries. (20) Eczema may be slightly more common in babies who are formula-fed. (21)

Babies are more likely to develop a food allergy if they have troublesome eczema in the early months of life. This is because healthy skin acts as a barrier, keeping out microscopic particles. When the skin barrier is broken by eczema, particles of food protein in the environment can enter the baby’s system, which may increase their risk of developing food allergies. (22) Eczema itself is mainly caused by a genetic tendency for the skin to dry out and become inflamed. (23)

If the only symptom your baby is experiencing is eczema, it is unlikely that a food allergy is causing it. If you notice that your baby’s skin is more inflamed after you, or they, eat or drink something in particular, it may be worth trying a restriction of those foods. Only exclude foods completely if you are seeing a specific reaction that occurs every time you or your baby have a certain ingredient. Babies are less likely to become allergic to foods they eat regularly, so it’s important not to exclude foods from their diet unnecessarily. This is why, in countries where food allergy is common, health authorities now often advise parents to include any common food allergens eaten at home into their baby’s diet as soon as solids are introduced.

A note on language
If you’ve been told that your baby is allergic, but they don’t have the symptoms described above, what’s going on? It may be a confusion about language. ‘Allergies’ is commonly used as a blanket term to cover allergies (in the medical sense of the word), plus other kinds of reaction to food which are not allergies, such as intolerances or sensitivities. In this article, we use the word ‘allergies’ in the medical sense.

If allergy is unlikely, why does my baby seem to react to what I eat or drink?

Although allergic reactions are very rare in exclusively breastfed babies, you may notice that sometimes your baby seems to react after you eat or drink something in particular. For example, eating foods with very strong flavours, or drinking coffee or alcohol, can affect how much milk your baby takes and their behaviour afterwards.

This is not an allergy (a full immune system response) but it may be a sensitivity or intolerance – and your close breastfeeding relationship with your baby has allowed you to tune into it. Babies with a more sensitive temperament may react more strongly to unfamiliar sensations or discomfort than placid babies. If your baby is unwell, or under extra stress, they may also react more strongly. You know your baby better than anyone: if you notice that your baby seems uncomfortable or unsettled when you eat or drink a certain thing, and is happier when you avoid it, you can trust your own experience and instincts.

If you choose to avoid a food or drink for a while, when you try it a few days or a few weeks later the sensitivity may have passed and you can go back to enjoying it. Or it may still bother your baby, and you might choose to avoid it for a bit longer. You may also find that you don’t need to exclude it altogether. For example, some mothers find that if they eat a problem food in a baked form their baby reacts less, or not at all. If your baby has been bothered by a food you eat, they’ll probably feel better soon after you stop eating it, though it might take a few days for their gut to go completely back to normal.

Some nursing parents decide to try an exclusion diet – completely eliminating a food, or foods, from their own diet for a period of time. This can be challenging to manage while caring for a baby, especially if the diet is continued for a long period of time. Strict exclusion diets are often not necessary. You can test out whether the improvement was due to cutting out the food by seeing what happens when you try eating it again. In the past, mothers have often been advised that an elimination diet may need to be several weeks long. This is not supported by scientific evidence, which shows that foods or other substances a mother has consumed can only be detected in very small quantities in her breastmilk and only for a few hours. Any change in symptoms caused by your diet should occur quickly. (12)

Other Questions

Q. Should I introduce solids before six months, as recent research seems to suggest?

A: Research has shown that early introduction of common allergy foods such as egg and peanut reduces the risk of developing allergy to these foods. As a result, most public health authorities, including the NHS (24), now suggest including allergens that your family eats in your baby’s diet when they are ready to start family foods (solids). National and international guidance recommends six months as being an appropriate time to introduce solids and, therefore, allergens. It is often harder to introduce solid foods earlier than this; the (usually ultra-processed) commercial products that make it easier have their own health risks. (25) The World Health Organisation advises that baby foods should be home prepared, locally available, and culturally appropriate (26).

Q. I thought I was not meant to feed my baby egg, peanut, etc. until they were over twelve months?

A. It used to be recommended that common allergens such as egg and peanut should not be introduced to babies until after the age of one year. However, current research shows it is better to introduce these foods as soon as your baby is ready to start eating family foods. (27, 28, 29)

You can find more information here about how to tell when your baby is ready to start family foods. If your baby is on a different timetable, for example because they were born prematurely, talk to your healthcare team about the appropriate timing for them.

Q. Does my baby have lactose intolerance?

A. Lactose is the main sugar in milk and there is lots of it in human milk – it helps fuel our babies’ huge brains! Humans have evolved to tolerate lactose until we are at least a few years old (the usual length of time our ancestors would have breastfed for). Throughout much of the world, especially in Asia, it’s common to develop lactose intolerance in adolescence as the enzyme lactase, needed to digest lactose in the gut, stops being produced. Many people of European and African heritage, though, have a ‘lactase persistence’ gene, which means they can tolerate large quantities of milk throughout their life. This is the most recent genetic mutation known in humans, appearing only a few thousand years ago.

A tiny number of babies have congenital (‘primary’) lactose intolerance, a very serious metabolic condition which is diagnosed soon after birth. Temporary (‘secondary’) lactose intolerance can occur in babies and young children during or after a nasty gastrointestinal illness, e.g. rotavirus infection. The virus damages the lining of the gut where the lactase enzyme is produced, meaning they temporarily
can’t digest lactose properly until the gut has healed. This can take a few weeks. In the meantime, expect green, perhaps explosive, poos and an uncomfortable, gassy baby! It’s a nuisance, and hard to see your baby uncomfortable, but it will get better by itself and it isn’t dangerous for your baby. If you’re worried, talk to your health visitor or doctor.

You can read more here about ‘lactose overload’ (secondary lactose intolerance).

Q. My baby has recently started solids and is exhibiting worrying symptoms – what should I do?

A. Again, if you are worried about your baby, speak to your doctor. Changes in bowel movements are common when solids are introduced (or when a child stops breastfeeding). You might find it helpful to review what foods you are offering your baby and try smaller volumes, aiming for unprocessed foods as close to their natural state as possible. If you notice that some days are worse than others, a food diary may be a helpful starting point.

Summary

  • Allergic – whole immune system – reactions to food are very rare in exclusively breastfed babies. Most babies diagnosed with a cow’s milk protein allergy are probably not allergic to it.
  • Allergic reactions usually happen within two hours of exposure to the food, are reproducible (they happen every time the food is eaten), and stop within two or three hours.
  • Allergic babies need to be seen by a doctor.
  • Completely excluding foods from your own diet can be difficult and is not often necessary.
  • Some breastfed babies are not allergic, but they do seem sensitive to one or more foods you eat. This may make them unsettled or cause other symptoms. You can experiment to see if it helps to eat that food less, or in a different form.
  • Including potentially allergenic foods in their diet as soon as babies are ready to start solids may reduce their risk of developing allergies to those foods.
  • Babies are less likely to become allergic to foods they eat regularly, so it’s important not to exclude foods from their diet unnecessarily.

Many families in the LLL community have experienced these issues with their babies and we are here to support you. LLL Leaders are available to listen to your concerns, and you might find it helpful to connect with other breastfeeding mothers to hear about their experiences too.

Written by Joanna Godden, Jayne Joyce, and Charlotte Allam, March 2025

Acknowledgements

Many thanks to Dr Robert Boyle for his help with this article. Dr Boyle is a children’s allergy specialist based at St Mary’s hospital in London, and a Clinical Reader in Paediatric Allergy at Imperial College London. He is a member of LLLGB’s Panel of Professional Advisors.

Special thanks to the team of mothers who reviewed the text: Anna Barnes, Rachel Cruddas, Lucy Ling, and Laura Mould.

References

  1. Wells R, McKay C, Makwana N, et al. National Survey of United Kingdom Paediatric Allergy Services. Clin Exp Allergy. 2022;52(11):1276-1290. doi:10.1111/cea.14198
  2. McGowan EC, Peng RD, Salo PM, Zeldin DC, Keet CA. Changes in Food-Specific IgE Over Time in the National Health and Nutrition Examination Survey (NHANES). J Allergy Clin Immunol Pract. 2016;4(4):713-720. doi:10.1016/j.jaip.2016.01.017
  3. Venter C, Pereira B, Grundy J, Clayton CB, Arshad SH, Dean T. Prevalence of sensitization reported and objectively assessed food hypersensitivity amongst six-year-old children: a population-based study. Pediatr Allergy Immunol. 2006;17(5):356-363. doi:10.1111/j.1399-3038.2006.00428.x
  4. Peters RL, Koplin JJ, Allen KJ, et al. The Prevalence of Food Sensitization Appears Not to Have Changed between 2 Melbourne Cohorts of High-Risk Infants Recruited 15 Years Apart. J Allergy Clin Immunol Pract. 2018;6(2):440-448.e2. doi:10.1016/j.jaip.2017.11.018
  5. McGowan EC, Peng RD, Salo PM, Zeldin DC, Keet CA. Changes in Food-Specific IgE Over Time in the National Health and Nutrition Examination Survey (NHANES). J Allergy Clin Immunol Pract. 2016;4(4):713-720. doi:10.1016/j.jaip.2016.01.017
  6. Venter C, Maslin K, Patil V, et al. The prevalence, natural history and time trends of peanut allergy over the first 10 years of life in two cohorts born in the same geographical location 12 years apart. Pediatr Allergy Immunol. 2016;27(8):804-811. doi:10.1111/pai.12616
  7. Li J, Ogorodova LM, Mahesh PA, et al. Comparative Study of Food Allergies in Children from China, India, and Russia: The EuroPrevall-INCO Surveys. J Allergy Clin Immunol Pract. 2020;8(4):1349-1358.e16. doi:10.1016/j.jaip.2019.11.042
  8. Botha M, Basera W, Facey-Thomas HE, et al. Rural and urban food allergy prevalence from the South African Food Allergy (SAFFA) study. J Allergy Clin Immunol. 2019;143(2):662-668.e2. doi:10.1016/j.jaci.2018.07.023
  9. Venkataraman D, Erlewyn-Lajeunesse M, Kurukulaaratchy RJ, et al. Prevalence and longitudinal trends of food allergy during childhood and adolescence: Results of the Isle of Wight Birth Cohort study. Clin Exp Allergy. 2018;48(4):394-402. doi:10.1111/cea.13088
  10. Allen HI, Wing O, Milkova D, et al. Prevalence and risk factors for milk allergy overdiagnosis in the BEEP trial cohort. Allergy. Published online June 20, 2024. doi:10.1111/all.16203
  11. Mehta S, Allen HI, Campbell DE, Arntsen KF, Simpson MR, Boyle RJ. Trends in use of specialized formula for managing cow’s milk allergy in young children. Clin Exp Allergy.2022;52(7):839-847. doi:10.1111/cea.14180
  12. Gamirova A, Berbenyuk A, Levina D, et al. Food Proteins in Human Breast Milk and Probability of IgE-Mediated Allergic Reaction in Children During Breastfeeding: A Systematic Review. J Allergy Clin Immunol Pract. 2022;10(5):1312-1324.e8. doi:10.1016/j.jaip.2022.01.028
  13. Calvani M, Anania C, Bianchi A, et al. Update on Food protein-induced enterocolitis syndrome (FPIES). Acta Biomed. 2021;92(S7):e2021518. Published 2021 Nov 29. doi:10.23750/abm.v92iS7.12394
  14. www.allergyuk.org/wp-content/uploads/2022/03/FPIES-Food-Protein-Induced-Enterocolitis-Syndrome-v3.pdf
  15. Kong KL, Burgess B, Morris KS, et al. Association Between Added Sugars from Infant Formulas and Rapid Weight Gain in US Infants and Toddlers. J Nutr. 2021;151(6):1572-1580. doi:10.1093/jn/nxab044
  16. Boustedt K, Roswall J, Twetman S. Free sugars and early childhood caries development: a prospective cohort study. Eur Arch Paediatr Dent. 2022;23(5):829-833. doi:10.1007/s40368-022-00745-3
  17. Anderson CE, Whaley SE, Goran MI. Lactose-reduced infant formula with corn syrup solids and obesity risk among participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Am J Clin Nutr. 2022;116(4):1002-1009. doi:10.1093/ajcn/nqac173
  18. Munblit D, Perkin MR, Palmer DJ, Allen KJ, Boyle RJ. Assessment of Evidence About Common Infant Symptoms and Cow’s Milk Allergy. JAMA Pediatr. 2020;174(6):599-608.doi:10.1001/jamapediatrics.2020.0153
  19. Acceptable medical reasons for use of breast-milk substitutes, World Health Organization, 2009.
  20. Langan SM, Mulick AR, Rutter CE, et al. Trends in eczema prevalence in children and adolescents: A Global Asthma Network Phase I Study. Clin Exp Allergy. 2023;53(3):337-352.doi:10.1111/cea.14276
  21. Soto-Ramírez N, Kar S, Zhang H, Karmaus W. Infant feeding patterns and eczema in children in the first 6 years of life. Clin Exp Allergy. 2017;47(10):1285-1298. doi:10.1111/cea.12998
  22. Tsakok T, Marrs T, Mohsin M, et al. Does atopic dermatitis cause food allergy? A systematic review. J Allergy Clin Immunol. 2016;137(4):1071-1078. doi:10.1016/j.jaci.2015.10.049
  23. Davari DR, Nieman EL, McShane DB, Morrell DS. Current Perspectives on the Management of Infantile Atopic Dermatitis. J Asthma Allergy. 2020;13:563-573. Published 2020 Nov 5. doi:10.2147/JAA.S246175
  24. www.nhs.uk/start-for-life/baby/weaning/safe-weaning/food-allergies/
  25. Ultra-processed foods (UPF) in the diets of infants and young children in the UK – What they are, how they harm health, and what needs to be done to reduce intakes, by Rachel Childs and Dr Vicky Sibson. First Steps Nutrition Trust, 2023.
  26. WHO Guideline for complementary feeding of infants and young children 6-23 months of age, World Health Organization, 2023
  27. Scarpone R, Kimkool P, Ierodiakonou D, et al. Timing of Allergenic Food Introduction and Risk of Immunoglobulin E-Mediated Food Allergy: A Systematic Review and Meta-analysis. JAMA Pediatr. 2023;177(5):489-497. doi:10.1001/jamapediatrics.2023.0142
  28. Skjerven HO, Lie A, Vettukattil R, et al. Early food intervention and skin emollients to prevent food allergy in young children (PreventADALL): a factorial, multicentre, cluster-randomised trial. Lancet. 2022;399(10344):2398-2411. doi:10.1016/S0140-6736(22)00687-0
  29. Young MC. Elimination Diets in Eczema–A Cautionary Tale. J Allergy Clin Immunol Pract. 2016;4(2):237-238. doi:10.1016/j.jaip.2015.10.009