Allergy – When to Start Weaning?
The optimum ‘weaning window’ has a long history of causing parental anxiety, but even health professionals can become confused over the variable guidelines on offer. Specialist paediatric allergy dietitian Dr Lisa Waddell casts light on the latest evidence and recommendations.
Introduction of solids to a baby, also known as complementary feeding, is commonly referred to as weaning in the UK. There is much confusion generally as to when and how to do this, and more so for children at risk of food allergies. This is not surprising as advice has changed instantly over the years.
History of weaning in the UK
Early 1900-1920s Paediatricians were advising no solid foods until 12 months of age, supplemented by cod liver oil and orange juice to prevent rickets and scurvy respectively (Fildes, 1998).
1930-1950 The age at which solids were introduced became earlier, as there were concerns that babies were missing essential iron and vitamins when given breast milk alone. Margarine was compulsorily fortified with vitamin D.
1950-1970s It was not uncommon for babies to start solids as young as three to six weeks of age. A survey in the UK found that the commonest age for starting solids was between three to four weeks of age and adding rusk or cereal to the bottle was also common practice (Oates, 1973). Introducing solids was generally viewed as a milestone achievement.
1970s-1980s The Present Day Practice in Infant Feeding report (DHSS, 1974) stated that ‘the early introduction of cereals or other solid foods to the diet of babies before about four months of age should be strongly discouraged’, due to concerns of contributing to the development of obesity. However, Wilkinson & Davies (1978) felt this was unrealistic based on the results of their own study. Successive versions of the DHSS report stated that few infants needed food other than milk before three months of age, but by six to eight months, nearly all babies required mixed feeding. Cod liver oil was substituted with vitamin supplements as part of the Welfare Food Scheme. National Dried Milk and subsequently infant milks, rusks and cereals were also fortified with vitamins A and D. Targeted campaigns of vitamin D supplementation, predominantly in Asian communities helped to reduce the incidence of rickets.
1990s The Department of Health (DH) report Weaning and the weaning diet (1994) recommended that: ‘Breastfeeding is the best form of nutrition for infants. Mothers should be encouraged and supported in breastfeeding for at least four months and may choose to continue to breastfeed as the weaning diet becomes increasingly varied. The majority of infants should not be given solid foods before the age of four months, and a mixed diet should be offered by the age of six months.’ The four to six month range was deliberate to account for the considerable individual variation in maturation and growth of the body’s systems. It was also stated that, ‘Weaning should not start before neuromuscular coordination has developed sufficiently to allow the infant to eat solids, nor before the gut and kidney have matured to cope with a more diverse diet’. Many practitioners understood this policy to mean that infants should be introduced to solids food at four months (17 weeks) rather than allowing for a more individualised approach. The weaning report also made recommendations for vitamin D supplementation; 10mcg daily for pregnant and breastfeeding mothers; 7mcg daily for breastfed infants over six months of age (from one month in those most at risk) and in infants taking less than 500ml infant formula.
2000 The Infant Feeding Survey, 2000 (Hamlyn et al, 2002) demonstrated that despite a movement towards later introduction of solids, almost half (49%) of mothers had introduced solids before 17 weeks.
In 2002, the World Health Organisation (WHO) published infant feeding recommendations which stated that, ‘As a global public health recommendation, infants should be exclusively breastfed for the first six months of life to achieve optimal growth, development and health. Thereafter, to meet their evolving nutritional requirements, infants should receive nutritionally adequate and safe complementary foods while breastfeeding continues for up to two years of age or beyond’. As a result, in 2003 the DH and NHS changed their recommendation to state that introduction of solid foods should occur at six months of age.
2004-present The debate continues relating to the fact that every child is an individual and a blanket approach of exactly six months of age for introducing solids is not realistic. The NHS Choices website now uses the term ‘around six months’, focusing on developmental signs of readiness (NHS Choices, 2013a). These developmental signs include self-sitting and co-ordination of hands necessary for self-feeding, which occurs around five months of age, and munching oral-motor activity and lateral tongue movements around six months (Cameron et al, 2012). These skills will determine ability to manage varying food textures. Late introduction of textures beyond nine months of age can cause later feeding difficulties (Northstone et al,2001; Coulthard et al, 2009
The concept of baby-led weaning (BLW) was first introduced in 2003 by Gill Rapley, in which the infant feeds themselves, with no help from an adult. More research is required to confirm whether this is a nutritionally safe method of feeding for all infants all of the time, or whether a more flexible approach should be considered combining the BLW responsive feeding philosophy with more traditional spoon feeding (Cameron et al, 2012).
In 2006, the Healthy Start Scheme replaced the Welfare Food Scheme as a means of promoting adoption of a healthy diet from birth, via vouchers for milk, fruit and vegetables and as part of this, free vitamins for socio-economically disadvantaged families was introduced in an attempt to tackle the re-emergence of rickets.
The latest National Infant feeding Survey – UK, 2010 (HSCIC, 2012) showed a reduction in early introduction of solids, with 30% of mothers having introduced solid foods by four months. Three quarters of mothers (75%) had introduced solids by the time their baby was five months old.
Introducing solids to a baby at risk of allergy What are the current UK recommendations?
The NHS Choices website currently recommends that some of the high allergenic foods such as milk, eggs, wheat, fish, shellfish, nuts and seeds should not be introduced before six months of age and they should be introduced individually, so that an allergic reaction to a specific food can be identified (NHS Choices, 2013b). Soya or other cereals containing gluten are not mentioned on their food allergy page and it is not specific about peanuts and tree nuts, although they are listed on the general weaning page (NHS Choices, 2013a). Current UK advice is still based on the DH’s weaning report (DH, 1994) which states, ‘Where there is a family history of atopy or gluten enteropathy, mothers should be encouraged to breastfeed for six months or longer. Weaning before four months should be particularly discouraged and the introduction of foods traditionally regarded as allergenic should be delayed until six months at the earliest’ (SACN & COT, 2011). Soya and gluten are considered amongst these key allergens.
Why is there so much conflicting advice on the timing of introduction of allergenic foods?
There is an increasing body of evidence to support the benefit of introducing allergenic foods between four to six months of age, but this is yet to be confirmed. It began following a report from the European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) in 2008 (Agostoni et al, 2008), stating that ‘solids should not be introduced before 17 weeks and not later than 26 weeks’ and that ‘there was no convincing scientific evidence that avoidance or delayed introduction of potentially allergenic foods, such as fish and eggs, reduces allergies, either in infants considered at increased risk for the development of allergy or in those not considered to be at increased risk’. This was closely followed by a review by the European Food Safety Authority (EFSA) who concluded that ‘introduction of complementary food into the diet of healthy term infants in the EU between the age of four and six months is safe and does not pose a risk for adverse health effects’ and would also ‘support the timing of introduction of gluten’ (EFSA, 2009). The theory is that repeated exposure of the immune system at an early age to allergenic foods via ingestion teaches the body to tolerate foods so that they will not cause an allergy as the child gets older.
One of the latest publications comes from the UK cohort of the EuroPrevall project; known as the PIFA (Prevalence of Infant Food Allergy) study (Grimshaw et al, 2013). The study found that 17 weeks is a crucial time point, with solid food introduction before this time being associated with a higher incidence of subsequent food allergy. In addition, they demonstrated a protective effect on food allergy development when cow’s milk was given in the infant’s diet concurrently with breast milk. The duration of overlap between cow’s milk and breastfeeding did not seem to be relevant, nor did the age of introduction. Concurrent introduction of other foods with breastfeeding could not be explored due to insufficient numbers. A further European study, the Protection Against Allergy Study in Rural Environments (PASTURE study), demonstrated that an increased diversity of complementary foods introduced in the first year of life might be protective against the development of asthma, food allergy and food sensitisation (Roduit et al, 2014).
The American Academy of Allergy, Asthma & Immunology (AAAAI) has recently produced an American guidance/advice sheet for families (2014) that is based on a paper by Fleischer et al (2013), and which recommends that weaning should occur between the ages of four to six months in accordance with the baby’s development, and that key food allergens do not need to be delayed beyond four to six months. The joint position statement from the Canadian Paediatric and Allergy and Clinical Immunology Societies acknowledges the increasing evidence towards earlier introduction of food, but in line with the UK they are awaiting further research before recommending introduction of solids before six months (Chan & Cummings, 2013). Interestingly, they do highlight the importance of ensuring regular, frequent consumption of the food once it has been introduced to maintain tolerance and state this may be as important as the timing of introduction.
Hopefully more definitive and consistent recommendations will be made once results of the EAT (Enquiring About Tolerance) and LEAP (Learning Early about Peanut allergy) UK trials become available in 2015. The EAT study was established to determine whether the introduction of six allergenic foods (cow’s milk, eggs, wheat, peanuts, fish and sesame) into the diet of infants from three months of age, alongside continued breastfeeding, results in a reduced prevalence of food allergies by three years of age. The LEAP study explores whether feeding peanuts to young infants at risk of developing allergy will prevent peanut allergy, or alternatively whether avoidance is better. Results for this study are expected by the end of this year.
The Scientific Advisory Committee on Nutrition (SACN) set out to review complementary feeding in children (SACN, 2011) and also produced a statement highlighting the fact there was insufficient evidence to make a change in recommendation regarding the timing of introduction of gluten in the diet at that time (SACN & COT, 2011). Their review is ongoing and one would hope that they will not complete their conclusions until results of the LEAP and EAT study are known.
What about other recognised food allergens?
The food allergens specifically identified by the DH weaning report (1994) and therefore the Allergy UK weaning factsheet comprise of the core eight food allergens commonly recognised as being responsible for 90% of food allergies (milk, egg, wheat, soya, fish, shellfish, nuts and peanuts) (Boyce et al, 2010). It is recommended that these foods are introduced individually, with a gap of three days between each new food, to enable identification of any food responsible for a reaction.
The Food Standards Agency (FSA), however, lists 14 major food allergens that food businesses will have to provide information on, as required by the new EU Food Information for Consumers Regulation 1169/2011, which comes into force in December 2014. The FSA has also produced a useful booklet on allergen labelling. Oats fall into the category ‘cereals containing gluten’ although this is not strictly true. However, a number of people with coeliac disease cannot tolerate oats and there is also a risk of cross-contamination of oats with gluten. As a result, the Allergy UK fact sheet (http://www.allergyuk.org/advice-for-parents-with-a-new-baby/weaning-your-baby-on-to-solids) does not include oats in the group of first cereals to introduce. Rice is included, although baby rice (often described as wallpaper paste by parents) is not a necessary part of the weaning process, especially if weaning doesn’t commence until the baby is developmentally ready. Rice is also recognised to cause allergic reactions in a few susceptible gut-allergic children. There is a move towards promoting vegetables as first weaning foods, and a large EU study known as Habeat is currently investigating strategies to promote healthy foods, particularly vegetables (Habeat, 2014). They recommend that plain vegetables should form first weaning foods and that repeated exposure increases acceptance of vegetables (Caton et al, 2012). Vegetables are least likely to cause food allergic reactions and hence are ideal first foods for all children.
Introduction of other food allergens listed by the FSA should not be specifically avoided when weaning as they are not likely to cause the majority of babies a problem, and emerging evidence and recommendations are to avoid delaying the introduction of potential allergenic foods (Agostoni et al, 2008; EFSA, 2009; Grimshaw et al, 2013; Roduit et al, 2014; AAAAI, 2014; Fleischer et al, 2013). A few children have been reported to develop an allergy to kiwi, but the incidence is low, and advice to specifically avoid kiwi is not warranted. Reactions to tomatoes and strawberries are commonly reported, but in the majority these tend to be more localised skin reactions associated with their acidic nature or due to their naturally high histamine content, rather than being a true allergic reaction. They should however be avoided if urticaria (itchy, raised nettle rash), angioedema (swelling of lips, eyes, face, tongue) or more serious symptoms of anaphylaxis develop following ingestion.
Is baby-led weaning suitable for babies at risk of allergy?
Baby-led weaning (BLW) is a method of introducing solids foods to an infant by allowing the infant to feed themselves hand-held foods instead of being spoon-fed by an adult (Rapley, 2003; Cameron et al, 2012). It is favoured as it encourages responsive feeding and improved eating patterns (Black & Aboud, 2011)
Evidence to support the safety of BLW, however, is still in its infancy, particularly with regard to nutritional adequacy and growth (Cameron et al, 2012). There are concerns about the fact that exclusively breast fed babies are likely to need to be introduced to a diet rich in iron from six months of age, such as meat, meat alternatives and iron-fortified foods such as baby cereals, as their endogenous iron stores are likely to be depleted, due to the low, albeit well-absorbed iron content of breast milk (Butte et al, 2002). Infants following the BLW method, however, are unlikely to consume breakfast cereals or red meat at six months of age. Townsend & Pitchford (2012), who concluded that BLW babies were better able to regulate their food intake, unfortunately did not look at biochemical measures such as serum ferritin or explore the fact that there was a tendency to underweight in those who followed BLW practices, although the numbers were small. Currently, no studies have been conducted to examine whether there is an increased risk of iron deficiency or faltering growth in this group of babies and further research is needed.
Whether the BLW approach will be suitable for babies at risk of allergy will much depend upon the outcome of the EAT and LEAP studies, and if the findings suggest that introduction of solids earlier than six months is beneficial, some help with feeding is going to be necessary. It is also helpful to introduce key allergens individually to identify the food causing the reaction, and therefore care over the type of family meals eaten will need to be taken if BLW is adopted, to ensure that the baby is only exposed to one new allergen at a time. Whatever method is used, however, responsive feeding practices (reacting appropriately to the child’s signals and development) are essential for the development of future healthy eating behaviours (Black & Aboud, 2011).
- Every baby is different. Introduce solids when your baby is developmentally ready, i.e when they can stay in a sitting position and hold their head steady, co-ordinate their eyes, hands and mouth so that they can look at the food, pick it up and put it in their mouth and can swallow food.
- If breastfeeding, continue to breastfeed while introducing solid foods.
- Start by introducing low allergenic foods such as vegetables followed by fruits. Refer to the Allergy UK weaning fact sheet for suggested order of introduction: http://www.allergyuk.org/advice-for-parents-with-a-new-baby/weaning-your-baby-on-to-solids.
- Expose baby to a range of textures as soon as possible. If developmentally ready, pureed foods should not be necessary for long if at all, and soft finger foods can be introduced from around six to seven months of age.
- Promote uptake of vitamin D supplementation in all breastfeeding mums, breast fed babies over six months of age (from one month in those most at risk) and in bottlefed babies taking less than 500ml daily.
- Ensure an iron-rich diet is provided from six months of age.
- Do not delay the introduction of allergenic foods after six months of age (the recommended age may be earlier following results of the EAT and LEAP study).
- Once allergenic foods have been given, keep offering them on a regular basis.
- The ideal compromise for introduction of solids in those at risk of allergy is to encourage self-feeding but also to offer the child food in a child responsive manner.
Source: Allergy UK