The benefits of breastfeeding have been exaggerated, a new study has suggested.
A comparison of siblings fed differently during infancy suggests breast milk is no better than bottled milk at improving long-term health.
Dr Cynthia Colen, from Ohio State University, said her findings are not meant to challenge established ideas, but could prevent women who cannot breastfeed from feeling stigmatised.
The benefits of breastfeeding have been exaggerated, a U.S. expert has claimed
Those promoting the 'breast is best' message, including the Department of Health, say a mother's milk wards off a host of ills.
NHS leaflets given to pregnant women and new mothers claim breastfeeding protects against obesity, allergies, asthma and diabetes.
But Dr Colen’s research suggests breastfed children perform no better than their siblings who are bottle-fed.
It showed they are no more likely to be obese and that they do not perform better academically.
Dr Colen also claims that children who are breastfed are more likely to develop asthma than those who are bottle-fed.
She said: ‘Many previous studies suffer from selection bias. They either do not or cannot statistically control for factors such as race, age, family income, mother's employment - things we know that can affect both breast-feeding and health outcomes.
Dr Cynthia Colen says siblings who are bottle-fed perform just as well in the long-term as those who are breastfed
‘Mums with more resources - with higher levels of education and higher levels of income - and more flexibility in their daily schedules are more likely to breastfeed their children and do so for longer periods of time.’
The NHS recommends that mothers breastfeed for about six months.
Dr Colen said: ‘I'm not saying breastfeeding is not beneficial, especially for boosting nutrition and immunity in newborns.
‘But if we really want to improve maternal and child health, let's also focus on things that can really do that in the long term - like subsidised day care, better maternity leave policies and more employment opportunities for low-income mothers that pay a living wage, for example.’
She used data from the 1979 cohort of the National Longitudinal Survey of Youth, a nationally representative sample of young men and women.
She analysed a total of 8,237 children made up of 7,319 siblings and 1,773 ‘discordant’ sibling pairs, where one was breastfed with the other given a bottle.
The study measured BMI (body mass index), obesity, asthma, hyperactivity, parental attachment and behaviour as well as scores predicting academic achievement in vocabulary, reading, maths, intelligence and scholastic competence.
Across all of the families, breastfeeding resulted in better outcomes in BMI, hyperactivity, maths, reading recognition, vocabulary word identification, digit recollection, scholastic competence and obesity.
But when restricted to siblings differently fed within the same families, scores reflecting breastfeeding's positive effects on 10 of the indicators were closer to zero and not statistically significant - meaning any differences could have occurred by chance.
The researchers believe this means the siblings who were all breastfed probably performed better because of other factors, such as socioeconomic status.
The most surprising finding was that children who were breastfed were at greater risk of asthma.
However, this could be because the data relied on whether people said they had asthma, rather than whether they had been formally diagnosed with the condition.
Dr Colen also says children who are breastfed are more likely to develop asthma than those who are bottle-fed
Dr Colen said: ‘Instead of comparing across families we are comparing within families completely taking into account all of those characteristics - both measured and unmeasured - that differ by family such as parental education, household income and race/ethnicity.
‘If breastfeeding doesn't have the impact we think it will have on long-term childhood outcomes then even though it's very important in the short-term we really need to focus on other things.
‘We need to look at school quality, adequate housing and the type of employment parents have when their kids are growing up.
‘We need to take a much more careful look at what happens past that first year of life and understand breastfeeding might be very difficult, even untenable, for certain groups of women.
‘Rather than placing the blame at their feet let's be more realistic about what breastfeeding does and doesn't do.'
Read more: http://www.dailymail.co.uk/health/article-2568426/Breast-milk-no-better-baby-bottled-milk-INCREASES-risk-asthma-expert-claims.html#ixzz2uSeG3jSs
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