Formula milk intended to cut the risk of eczema and allergies is not effective, researchers say today.
Researchers at Imperial College, London, also raised questions about the methods used in studies of the formula – asking whether enough was done to encourage women to breast-feed when they took part.
There is some evidence that dietary exposures in infancy can influence the risk of immune mediated health conditions such as allergic and autoimmune diseases, researchers say. Some have pointed specifically at early exposure to intact cows’ milk protein in infant formula.
As a result, current infant feeding guidelines in North America, Australasia, and Europe recommend the use of hydrolysed formula in the first four to six months, if the baby is not exclusively breastfed.
To update the current research base, Dr Robert Boyle of Imperial College London, UK, and colleagues reviewed the findings on 37 trials of hydrolysed formula, carried out between 1946 and 2015. Together, the trials including over 19,000 participants.
"There was evidence of conflict of interest and high or unclear risk of bias in most studies," report the team in the BMJ.
"Overall there was no consistent evidence that partially or extensively hydrolysed formulas reduce risk of allergic or autoimmune outcomes in infants at high pre-existing risk of these outcomes," they found.
The authors add: "There was no evidence to support the health claim approved by the US Food and Drug Administration that a partially hydrolysed formula could reduce the risk of eczema nor the conclusion of the Cochrane review that hydrolysed formula could reduce the risk of allergy to cows’ milk."
Dr Boyle said: "Not only did we find no evidence of reduced risk from hydrolysed formula, but we found very few studies which were methodologically sound and without a conflict of interest.
"This raises questions about whether enough was done to promote breastfeeding to the mothers in those studies."
Professor Mary Fewtrell, of the Royal College of Paediatrics and Child Health, said: “Current advice is that infants who are at risk of allergy and who are not exclusively breast-fed should receive a hypoallergenic formula rather than a standard formula.
"However, this new review of the evidence suggests that there is no consistent advantage to using a hypoallergenic formula over a standard formula for preventing the development of allergy. Current advice may therefore need to change, and this is currently being reviewed by the Food Standards Agency.”
Boyle, R. J. et al. Hydrolysed formula and risk of allergic or autoimmune disease: systematic review and meta-analysis. BMJ 9 March 2016; doi: 10.1136/bmj.i974 [abstract]
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