Australian guidelines advising mothers to exclusively breastfeed their babies until six months could be putting children at risk of allergies and coeliac disease, a controversial study suggests.
A review of breastfeeding research published in the British Medical Journal earlier this year said there was emerging evidence that breast milk alone did not provide enough nutrition for infants.
The authors, from several leading child health institutes in Britain, said although breast milk offered babies many health benefits, including protection against infection, studies in the past decade showed babies denied solid foods before six months could be at higher risk of wheat allergy, coeliac disease (permanent intestinal intolerance to dietary gluten) and iron deficiency anaemia - a condition that can cause irreversible neurodevelopmental damage.
The authors also suggest that exclusive breastfeeding in the first six months may reduce the window for introducing new tastes, particularly bitter taste that may help toddlers eat green leafy vegetables. This could encourage unhealthy eating later in life and lead to obesity, they said.
The lead author of the review, Dr Mary Fewtrell, said the findings should prompt a review of the British government's guidelines, which together with Australia's National Health and Medical Research Council (NHMRC) and the World Health Organisation recommends exclusive breastfeeding until six months.
A report said three of the four authors had ''performed consultancy work and/or received research funding from companies manufacturing infant formulas and baby foods within the past three years'', but Dr Fewtrell denied there was a conflict of interest. ''This is not an attempt to promote commercial weaning foods,'' she said.
The deputy chairman of the NHMRC dietary guidelines working committee, Professor Colin Binns, who is reviewing the evidence for new breastfeeding guidelines to be released this year, said the British review offered no compelling evidence to change the advice that exclusive breast milk was best for infants.
Professor Binns, from Curtin University's School of Public Health, said research showed the introduction of nutritious solid foods between five and seven months was ideal and that doing so earlier could cause a baby to become overweight, increasing the chance of obesity later in life.
He said introducing foods too early could expose a baby to bacteria that caused diarrhoea and cause a mother's breast milk to dry up if feeding became more sporadic as a result. ''Breast milk is by far the most nutritious food a baby can be given,'' Professor Binns said.
The senior lecturer in midwifery and breastfeeding at RMIT, Jennifer James, said advice should be changed only on the basis of large, rigorous studies. ''We should not be changing our advice to mothers until the evidence is much stronger,'' she said.
The Australian Breastfeeding Association and Royal Women's Hospital in Melbourne said they would not change their advice based on the report.
Melbourne mother Kate Sheahan said she started feeding her 4½-month-old son, Will, mashed sweet potato this month because he seemed curious about food and ready for it.
Ms Sheahan said she was confident it was the best thing for him. ''He's a very happy, healthy baby so if it offers more protection against problems like coeliac disease, then that's a real positive,'' she said.