Babies who are breast fed cope better with stress in later life than bottle-fed babies, research shows.
Children who were bottle-fed as babies coped less well with stress
Among almost 9,000 children aged 10, those who had been bottle fed as a baby found it harder to deal with stressful events such as parental divorce.
The Swedish researchers believe close physical contact and mother-baby bonding during the first few days of life may be important factors.
Their work appears in Archives of Disease in Childhood.
The children's teachers were to rate the anxiety of their pupils on a scale of zero to 50, while parents were interviewed about major family disruption, including divorce or separation, which had occurred when their child was aged 5-10.
The Karolinska Institute team also looked at other factors that might influence or be linked with a child's reactions to stress and coping mechanisms, including maternal depression, parental education levels, their social class, and smoking habits.
The findings held true, irrespective of these other factors.
The children whose parents had divorced or separated were more likely to have high anxiety than their peers.
Specifically, breast-fed children were almost twice as likely to be highly anxious, while children who had been bottle fed were over nine times as likely to be highly anxious about parental divorce or separation.
Security and bonding
The authors stress that their findings do not mean breastfeeding itself makes children cope better with life stress.
Rather, breastfeeding might affect the quality of the bonding between mother and child, and the way in which the two relate to each other.
This close physical contact might make the baby feel more secure and this might make them better able to handle stress and anxiety in later life, for example.
Animal studies show physical contact between mother and baby during the first few days of life can feed the development of brain pathways crucial in coping with stress.
Rosie Dodds of the National Childbirth Trust said: "This study uncovers another potential advantage associated with breastfeeding.
"Of course it is difficult to control for the factors that both make a mother more likely to breastfeed and influence the other decisions that she makes as a parent.
"There is also some evidence that mothers who are breastfeeding are able to cope better with some types of stress as a result of their hormone balance, and this may make a difference to the baby's developing response to stress."
Health experts say that breastfeeding has benefits for both mother and child.
These include a reduced risk of allergic conditions such as eczema and asthma for babies and a lower risk of breast cancer for mothers.
The World Health Organization recommends that mothers should feed their babies on breast milk alone for the first six months of life.