Food allergies: probiotics, breastfeeding, age of introduction of solid foods and infant feeding guidelines

Article written by Dr Susan Tawia, Senior Scientific Information Officer, Breastfeeding Information and Research team, for the February 2014 health professional member eNewsletter.

The Australian NHMRC Infant Feeding Guidelines: Summary (NHMRC 2013) states clearly that:

‘In Australia, it is recommended that infants be exclusively breastfed until around 6 months of age when solids are introduced. It is further recommended that breastfeeding be continued until 12 months of age and beyond, for as long as the mother and child desire.’

‘Introducing a variety of solid foods around the age of 6 months is consistent with reducing the risk of developing allergic syndromes.’

It is important to emphasise at this point that ‘around 6 months’ does not mean 4–6 months, it means close to 6 months when the infant shows signs of being interested in tastes of food and is developmentally ready to eat and swallow suitable foods.

Further recommendations are made in the infant feeding guidelines regarding the transition to solid food:

  • Introduce solid foods at around 6 months, to meet the infant’s increasing nutritional and developmental needs
  • To prevent iron deficiency, iron-containing nutritious foods should be included in the first foods and
  • Foods can be introduced in any order provided iron-rich nutritious foods are included and the texture is suitable for the infant’s stage of development

 These recommendations were developed after exhaustive review of the research literature by a large team of experts and take into account the considerable evidence that exclusive breastfeeding to 6 months has many health and developmental benefits for the young infant and ‘breastfeeding may be associated with a reduced risk of atopic disease in infants with and without a family history of atopy.’ (NHMRC 2013)

Recently, the marketing of probiotics as dietary supplements has moved towards the pregnant woman and the infant with claims that they nurture healthy digestive health in infants and children. There is no recommendation for the use of probiotics in Australian infants in the Australian NHMRC Infant Feeding Guidelines: Summary (2013).

A probiotic is an oral supplement that contains sufficient microorganisms, specifically bacteria, to alter the gut microflora. The most common groups of probiotics are: Lactobacillus, Bifidobaterium, Streptococcus and Saccharomyces boulardii.

The Royal Children’s Hospital (RCH), Melbourne recently reviewed the evidence for the use of probiotics for infants and children (Royal Children’s Hospital 2014). With regard to food allergy, the RCH review referred to a Cochrane review that showed that the administration of probiotics had no apparent effect on the prevention of food allergy.

A very recent systematic review, undertaken on behalf of EAACI Food Allergy and Anaphylaxis Guidelines Group (de Silva et al 2014), has summarised the evidence about the most effective ways to prevent food allergy in children and adults.

Importantly, the review separated the research studies into two groups, those involving high- and normal-risk families, while looking at prevention strategies in (1) pregnant women; (2) breastfeeding mothers; (3) during infancy and (4) during childhood and adulthood.  The key findings regarding probiotic use, breastfeeding and the introduction of solids are presented in Table 1.

Table 1.  Summary of evidence about food allergy prevention strategies: probiotics, breastfeeding and age of introduction of solids. Modified from de Silva et al 2014.

Strategies

Studies

Findings about preventative effects in those at high risk

Findings for normal or unselected populations

Antenatal strategy

Maternal probiotic supplements

1

One randomised trial found a benefit for sensitisation, but was inconclusive overall

 

Strategy targeting breastfeeding mothers

Maternal probiotics when breastfeeding

1

One randomised trial found no protective effect

 

Strategies targeting infants

Breastfeeding

11

One systematic review found that most studies of breastfeeding in those at high risk identified a protective effect. Two cohort studies suggested no benefit and that exclusively breastfeeding may even increase the risk of food allergy

One systematic review and three cohort studies found that breastfeeding was associated with a reduced risk of sensitisation or food allergy, three cohort studies suggested an increased risk and three cohorts found no association.

Infant probiotic supplements

7

Four trials found no evidence of a benefit

Two systematic reviews and one trial found no evidence of a benefit

Age at introduction of solids

7

Two cohort studies found no benefit from delaying the introduction of solid foods longer than 4 months

One systematic review and two cohort studies found no benefit of delaying the introduction of solid foods longer than 4 months. Two cohort studies found reduced food allergy when solids were introduced earlier than 4 months

The review highlights that:

  • the evidence is not strong enough to recommend that pregnant or breastfeeding women should change their diet or take supplements to prevent allergies in infants at high or normal risk
  • there were mixed findings about the preventative benefits of breastfeeding for infants at high or normal risk which reflects, to a large extent the difficulty of this type of research study since a randomised controlled trial would be unethical
  • probiotics do not protect infants at high or normal risk from developing food allergy
  • delaying the introduction of solid foods beyond 4 months did not have any preventative benefits in those at high or normal risk.

It may be the way the last point has been construed that has given rise to ‘around 6 months’ being interpreted as ‘4–6 months’. Just because delaying the introduction of solid foods longer than 4 months does not seem to confer any further protective benefits, it doesn’t mean it is the best or preferred time that solids should be introduced.

There is evidence accumulating that exclusive breastfeeding for 6 months confers considerable health benefits to infants, even in developed countries like Australia (see review Tawia 2011).

The introduction of solids at ‘around 6 months’ balances the need to minimise sensitisation to food and the development of food allergies with the short- and long-term health and developmental benefits of exclusive breastfeeding to 6 months.

Abbreviations: EAACI – European Academy of Allergy and Clinical Immunology

 

 

References

de Silva D, Geromi M, Halken S et al 2014, Primary prevention of food allergy in children and adults: systematic review. Allergy 2014 Jan 16. doi: 10.1111/all.12334. [Epub ahead of print]

NHMRC 2013, Infant Feeding Guidelines: Summary. National Health and Medical Research Council, Canberra.

Royal Children’s Hospital, 2014 Community Paediatric Review: probiotics for infants and children. Vol 22 No 1 February www.rch.org.au/ccch/cpreview accessed 17/02/14.

Tawia S 2011, The evidence to support exclusive breastfeeding for 6 months and then the introduction of solids. Topics in Breastfeeding Set XXIII March 2011, Lactation Resource Centre.

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