Weaning and Food Allergies

Worrying about a potential food allergy is a real concern for most parents when they start to wean their baby. How will you know if they are going to be allergic to a food? Could they have a life threatening reaction? Its scary stuff!

However, the vast majority of babies will be absolutely fine. Food allergy – although well known about – is extremely rare. Having said that a child is more likely to develop an allergy if they have a parent or sibling who has an allergic condition whether that be asthma, eczema, hay-fever or a food allergy.

There is medical evidence that suggests breastfeeding exclusively for the first 4-6 months (which means no bottles of formula at all) has a protective effect against your baby developing an allergy. Avoiding eating certain foods while breastfeeding won’t make a difference, so there’s no need to restrict your diet.

So what should you do?

For babies who don’t have parents or siblings with allergies

Start introducing solid food to your baby in the normal way. You should be starting at around 6 months when your baby is developmentally ready click here for information on knowing when your baby is ready.  There’s no need to introduce foods singly, mix things up a bit you can create some wonderful flavour combinations. Nutrition is critical at this stage in your baby’s development so avoid sticking to just fruit and vegetables for weeks on end. They need protein, energy dense foods and lots of iron. Click here for more information on the critical nutrients for babies and the best weaning foods.

For babies who have a parent or sibling with asthma, eczema, allergy or hay-fever

Start when your baby is developmentally ready which is usually around 6 months (26 weeks). You can feed them all the usual fruit and vegetable foods at the start of weaning and don’t forget the importance of other foods in order for them to be properly nourished with those critical nutrients. However when it comes to the top 14 allergenic foods, you want to introduce these one at a time alongside their other food, leaving 3 days in between each one to observe for any reaction. The top 14 allergenic foods are:

  • Eggs
  • Milk including formula, cows milk, goats milk and all other animal milks
  • Shellfish including prawns
  • Fish
  • Soya
  • Peanut
  • Wheat
  • Tree nuts
  • Sesame
  • Celery
  • Sulphur dioxide - used as a preservative in dried fruit
  • Lupin – a flower but its often found in flour and wheat products as a contaminant
  • Molluscs which are mussels, clams, oysters
  • Mustard


Its very unlikely that your baby will have some of these foods during weaning (such as molluscs), nevertheless they are in the top 14 and concerned parents need to be aware.

Allergies can be immediate or delayed. The symptoms you might see immediately are vomiting, hives or a red rash, swelling in the mouth or throat, wheezing, shortness of breath, and difficulty breathing.  Delayed reactions are more likely to be colic-like symptoms, eczema, vomiting, diarrhoea, constipation, a stuffy, itchy nose and poor weight gain and growth. If your baby experiences breathing difficulties this is a medical emergency so dial 999 for help.

Food allergies are managed by avoiding the food that’s caused the reaction. If this is milk, wheat, soya or egg or a combination of several foods please ask to see an NHS dietitian who specialises in children or find one privately like me (or via freelancedietitians.org). This is extremely important as getting the right balance of critical nutrients needed for growth and brain development in the first 2 years of life can be a challenge. A dietitian will also help you avoid all traces of the offending food and advise on how and when to reintroduce it safely.

If you do have allergies in the family and are worried that your baby will react, ask your GP to make a referral to a paediatric allergy specialist at your local hospital where allergy testing can be arranged before you start weaning. Make sure that you do this well in advance though, as waiting lists can be long and it’s critical that you don’t delay the introduction of solid food.

If you are concerned about food allergies or suspect your baby is allergic to food contact me for further advice. I’m always happy to help.