Weaning: Allergens

Owing to the fact allergies are on the rise in young children, it is no surprise parents are concerned about introducing foods commonly allergenic when weaning. Additionally, since the advice on this has changed over recent years it can also be a little confusing for parents too. Here we explain what a food allergy is, how it differs from a food intolerance, and what the advice is around introducing these when weaning.

Food allergies vs. intolerances

Food allergies and intolerances fall under the umbrella of ‘food hypersensitivities’, which describes when someone has an adverse reaction to food. If this reaction is a result of the immune system response it is a food allergy, otherwise it is a food intolerance.

Food allergies have one further layer, and that is whether they are IgE or Non-IgE mediated; which essentially describes the component within the immune system that is leading the response. Immunoglobin E (IgE) is an antibody produced by the immune system. In an IgE-mediated allergy, the antibody responds to a food protein and triggers a reaction by the immune system. This will typically be rapid, within roughly two hours after contact with the food, and symptoms vary from mild to severe and, in some instances, life-threatening (e.g. anaphylaxis). Non-IgE allergies are when this antibody is not involved and instead the onset of symptoms can be slower, occurring up to a few days later.  

Allergic symptoms

Symptoms of allergic reaction can include; swelling or itchiness around the eyes, mouth or throat, difficulty breathing, skin irritations (e.g. eczema and hives) and digestive complaints such as constipation or diarrhoea. However, this is not an exhaustive list and it is worthwhile familiarising yourself with the full list of possible symptoms* before commencing introduction.

*For full list of the symptoms to look out for and further advice on allergen introduction head to Allergy UK.

The allergens

The most common food allergens in children are cow’s milk, eggs, shellfish, fish, soy, sesame, peanuts*, tree nuts* and wheat. In the UK, legislation requires that all of these plus mustard, celery, sulphites, molluscs and lupin are listed on pre-packaged food labels. UK guidelines advise introducing all these common allergens from around 6 months when weaning. There is no evidence to suggest delaying introduction reduces the risk of allergic reactions. In fact, there’s some evidence to suggest delaying introduction of peanuts and hen’s eggs until after 12 months may increase the risk of allergic reaction. Delayed introduction of gluten is not shown to reduce the risk of coeliac disease.

*Ensure peanuts & tree nuts are finely chopped or ground when served to those under 5 years old.

How to introduce allergens

  • When introducing allergens, first make sure your little one is well and doesn’t have a cough, common cold or stomach upset as the symptoms of these can be confused as a reaction to the food.
  • When starting, introduce each allergen one at a time, leaving roughly three days in between each.
  • Start with small amounts, working up to a full portion over 3-4 days.
  • Once your little one is tolerating a new food continue to provide it in their diet whilst continuing to introduce new foods.
  • If you suspect a reaction to a food, discontinue the introduction and seek medical advice.

You may be particularly cautious of introducing allergens if your little one has a known food allergy, eczema or asthma, or there is family history of such. Whilst these factors do not necessarily mean your little one will have an allergic reaction, it is advised that you seek medical advice from your health care professional before proceeding.

It’s worth noting that certain acidic foods, such as strawberries, tomatoes and citrus fruits, can cause redness (particularly around the mouth) upon consumption. This is likely a contact reaction, rather than an allergy. A baby’s skin is very sensitive, and may similarly become irritated if you rub an allergen on it. For this reason, rubbing allergens on the skin is not a recognised way of introducing an allergen and determining if your child may be allergic.

Weaning: The Fundamentals

You might also like our free download, Weaning: The fundamentals

What is ‘weaning’?

‘Weaning’, or ‘complementary feeding’, means introducing solids to your baby. Weaning commences when your baby has developed enough to progress on to solid foods. The World Health Organisation (WHO) encourages this to be termed ‘complementary’ feeding, since its purpose is to diversify an infant’s diet alongside the nutritional supplementation of breast milk or infant formula.

When should we start?

Whether you choose to feed your baby breast milk or infant formula, it’s not until 6 months, and no earlier than 4 months (17 weeks) that weaning should begin. At this age, your baby’s digestive system, kidneys, and nerves (which all play an important role) should have developed enough for them to start with solid foods. Up until this point, infant formula or breastmilk is nutritionally complete and provides all the fluid and energy required for growth and development as well.

The NHS advise the signs of readiness to wean are:

  • stay in a sitting position, holding their head steady
  • coordinate their eyes, hands and mouth so they can look at their food, pick it up and put it in their mouth
  • swallow food (rather than spit it back out)

There are some other behaviours that can be mistaken for readiness, such as your baby being hungrier, putting their fist in their mouth, or waking in the night, but these are not necessarily signs of hunger or readiness.

If your child was born prematurely, please speak to your healthcare professional on the right time to start weaning.

Why 6 months?

Solid foods are introduced from around 6 months as a baby’s stores of some nutrients, such as iron, begin to run out. Up until this point, milk has been nutritionally sufficient as your baby has stores of the nutrients it doesn’t provide.

As well as being nutritionally important, weaning is also integral for your baby’s physical and mental development. Motor skills and coordination will develop with the introduction of solids (working out just how to get that food into their mouth), and the action of eating develops the muscles required for speech. Additionally, whilst suckling and sucking are inherent behaviours, munching and chewing are learned behaviours that require exposure to different textures to develop.

What to offer?


Traditional weaning is when babies are introduced to solids through gradual texture progression and spoon-feeding. Transitioning from liquid breast milk or infant formula, babies are encouraged to adapt to solids and learn through introduction to textures more similar to liquids initially (purees) before moving on to more solid consistencies. After purees, mashed foods then chopped foods are introduced. Parents help by feeding the baby off of a spoon.

In the UK, ‘finger foods’, which are foods that are of a size and consistency appropriate for a child to pick up and eat with their fingers, are also advised in traditional weaning from around 6 months. However, they are not typically a large part of the diet until around 8-9 months, allowing time for babies to adapt to the textures offered.

Baby-led weaning differs from this approach as the infant is encouraged to completely self-feed from the outset. Parents provide the baby with a range of foods and allow the baby to feed themselves, usually with them or the wider family all eating meals at the same time. This usually means there’s a reliance on finger foods from the outset since pureed foods require spoon feeding and babies do not have the dexterity to do this until a little later.

(see full post on traditional vs baby-led weaning here)

What to start with?

Foods are divided into four groups according to their nutritional composition, so that by selecting foods from each a varied diet is achieved. This means both varying food groups, as well as the foods chosen with that group, is important.

The four food groups are:

  • STARCHES eg. potatoes, rice and pasta
  • PROTEIN eg. meat, fish, eggs and pulses
  • DAIRY eg. milk, cheese and yoghurt

Owing to evidence that early and repetitive introduction of bitter vegetables, such as broccoli and kale, increases acceptance of these foods later in life, it’s common to start with these foods. Following this, sweeter vegetables, fruit, soft cooked proteins (such as meat and fish), starches (such as pasta, noodles and bread) and full-fat dairy (such as no added or low sugar yoghurts and custards) can be introduced.

What’s off the menu?

  • High salt and sugar foods, as early introduction can increase preference for these foods later in life.
  • Whole nuts and seeds and small fruits, these should be finely chopped or ground owing to choking risk.
  • Soft and unpasteurised cheese, as these can contain a harmful bacteria called Listeria.
  • Raw shellfish and some specific fish; shark, swordfish and marlin. These fish contain high levels of mercury.
  • Raw eggs, unless British Lion quality. Eggs carry the risk of Salmonella.
  • Honey, owing to the risk of Infant Botulism.


(see full post on Allergens for more information on this)

Cautiously offer the common allergens from around 6 months of age; milk, peanuts*, tree nuts*, seeds*, eggs, fish, shellfish (well cooked), sesame, soy, and wheat. Offer one at a time, and start with small amounts, monitoring for allergic symptoms. Should no symptoms occur, build up to a full portion of the food over 3-4 days. Once the food is tolerated in the diet, continue to offer regularly.

If your baby has a known allergy or eczema, or there is history of eczema, asthma or hay fever in the direct family, speak to a healthcare professional as earlier introduction of certain allergens may be advised.

*Ensure peanuts, tree nuts and seeds are offered ground or finely chopped to those under 5 years of age, to avoid choking risk.


Use only open or free-flow cups when giving your little one a drink to protect their teeth.

In terms of what should go into that cup, from 6-12 months only water and breast milk or infant formula should be offered with or between meals. Other options, such as fizzy drinks, flavoured milks, fruit juices and smoothies, have a high sugar content and risk causing tooth decay. 

It’s important to note that ‘Follow-on’ formula is not necessary if they’re weaning well, as the nutrients that it is fortified with your baby will now be getting from solid foods. If you are using infant formula rather than breast milk, it might be that you need to supplement this with water in hotter months (breastmilk will adapt to ensure the water content is sufficient).

Whilst only breast milk, infant formula or water are appropriate drinks, full fat cow’s, goat’s or sheep’s milk can be used in cooking. It is just advised that milk alternatives – soya, almond, oat, coconut etc. – are avoided until 1 year unless you’re advised to use plant-based alternatives by a healthcare professional eg. if your little one has cow’s milk protein allergy. In any case, rice milk should be avoided for those under 5 years of age.

At 1 year of age, when your baby should be getting the majority of their nutritional needs from food, whole cow’s milk can be introduced as a drink. Unsweetened, fortified milk alternatives can also be offered as drinks now and infant formula is no longer necessary.

How much?

There are no portion size guidelines for babies so follow their lead, and try to learn their hunger and fullness cues. Small amounts of foods should be offered first, with quantity and variety slowly increasing with age, remembering that it will only be tiny tastes to start!

Since the first foods baby is introduced to are in small quantities, they are still quite reliant on breast milk or infant milk for the energy density and macronutrients required. With age progression, milk feeds should be slowly reduced as food intake increases.

Choking vs Gagging

Whether your little one is starting on pureed foods, finger foods or both, a common concern for parents is choking. It is advisable to attend a first aid course on this topic, and head to a reputable source (such as the Red Cross) for instruction on how to respond to choking.

Babies have a very sensitive gag reflex which means gagging can be a regular occurrence, but it’s important to remember that it’s normal. In response, remain calm and allow your little one to respond naturally, and never try and fish the food out as this risks pushing it further in and causing a choking hazard.

The trouble lies in differentiating gagging from choking, the latter being far more serious, and the key is sound. Gagging means your little one will be coughing and spluttering, therefore air is getting through. When choking, the airway is blocked and no sound can be made, requiring immediate attention.

As well as being prepared with the knowledge of what to do should choking occur, here are a few other important recommendations to reduce the risk of choking:

  • Avoid foods that are high choking risks, such as:
    • Whole nuts (which shouldn’t be given to your little one before 5 years). Offer these finely chopped or ground.
    • Whole small fruits, such as grapes and cherries – chop these up before serving.
    • Dried fruits. Again, you can chop these up and serve.
    • Raw, hard foods, such as carrots, which can easily be broken and form a choking hazard. Soften these by cooking before serving.
    • Remove tough skins, pips & seeds from foods.
  • Wean when ready, not before 4-6months. If you’re unsure, ask your healthcare provider.
  • Ensure your baby is always sat upright when eating.
  • Never leave your little one unsupervised whilst eating.

Last, but not least…have fun!

If eating is fun and enjoyable for your little one it will support their long-term relationship with food. Remember, they are at the start of their learning journey when it comes to food. Don’t put too much pressure on yourself to “get it right”, you’re learning about them too so focus on what’s within your control. Offer a variety of foods, ensure the mealtime is relaxed and free of distractions and, ideally, eat with them as this aids their learning.

Dietitians, Nutritionists and Nutritional therapists – what’s the difference?

Registered Dietitians (RD) are regulated by law and the title ‘dietitian’ is protected by statute. To register requires at least a university degree in Nutrition & Dietetics and 1000 hours practical work experience. Dietitians can work clinically within the NHS, working with patients to treat medical conditions, as well as many other areas such as in food industry and freelance.

Registered (Associate) Nutritionists (ANutr/RNutr) meet requirements of the Association for Nutrition (which includes achieving a degree nutrition), and voluntarily register to be governed by them. After 3yrs+ experience ANutr can apply to become RNutr. ANutr & RNutr can work across many areas, but would require additional qualifications to work clinically.

‘Nutritionist’ as a standalone is not a regulated title, it is therefore not governed and there are no educational requirements to use the title.

‘Nutritional Therapist’ is also not a regulated title. Nutritionally Therapists have usually completed a course meeting the National Occupational Standards for Nutritional Therapy (equivalent to level 5 diploma). FHT, CHNC and GRCCT are regulatory bodies that can be voluntarily joined.