Newborns who are bottle fed are twice as likely to develop asthma
Scientist say babies should be exclusively breast fed for at least the first three days of their lives.
Bottle fed babies are almost twice as likely to develop asthma, according to scientists.
New research claims new mothers should exclusively breastfeed their babies in the first three days of life.
Scientist in Japan tested 302 babies and came up with the results that not only does breast milk contains nutrients that protect against infections and allergies, but the sheer physical effort involved in suckling also boosts lung strength.
Professor Mitsuyoshi Urashima who headed up the research said: "The findings suggest asthma can be prevented by avoiding cow's milk formula supplementation at birth."
Of the 302 Japanese infants in the study, at least one parent or sibling suffered with an allergy
By their second birthday only 15 of the 151 exclusively breastfed for at least the first three days of life - around ten percent - had asthma.
This compared to 27 (18%) of the other 151 randomly selected to receive small amounts of cow's milk formula as well.
Prof Urashima, of the Jikei University School of Medicine, Tokyo, said: "Asthma developed in significantly fewer children breastfed for at least the first three days of life than in children breastfed with supplementation from cow's milk formula from the first day."
Asthma is one of the most common chronic diseases - with prevalence rising during the past 60 years.
In the UK it affects almost one in ten people - 1 .1 million children and 4 .3 million adults.
The World Health Organisation recommends breastfeeding for at least six months after birth because of general benefits for the child.
But a study a decade ago suggested introducing cow's milk in an infant's diet within the first two weeks of life reduced their risk of becoming allergic to the food.
Japanese maternity wards encourage breastfeeding, but some, including Jike University Hospital where the trial was carried out, allow mothers or nurses to give babies a little formula a few hours after birth.
Prof Urashima said: "In this randomised controlled trial, by avoiding exposure to cow's milk formula for at least the first three days of life, the risk of asthma appeared to have been decreased."
He said chemicals in human milk may play a role in destroying disease causing bugs while also improving gut bacteria.
The findings published in JAMA Network Open back previous research that has suggested babies fed formula milk are more prone to asthma because it alters their microbiome.
Britain has some of the lowest breastfeeding rates in the world, with just one per cent of mothers feeding their babies naturally for six months.
This is despite the health watchdog NICE recommending that babies be breastfed exclusively for their first six months of life.
Most formulas are based on powdered cow's milk.