Women who eat oily fish in the second half of pregnancy are more likely to give birth to stronger children, according to a new study.
Scientists compared mothers who took oily fish supplements with those who did not and found the children in the first group put on healthy weight more quickly in their first six years.
This was mainly in the form of bone density rather than unhealthy fat.
Previous studies in animals have shown that supplementing the diet with fish oil during pregnancy affects adipogenesis – the development of fat cells.
But while trials in humans have shown pregnant women with a higher intake of fish oil give birth to higher birth weight babies, the impact on children later in life has been unclear.
Oily fish include salmon, mackerel, sardines, trout and herring.
Professor Hans Bisgaard, who led the research at Copenhagen University said: “Diet during pregnancy and infancy is an important determinant for children’s development and health.
“In particular, intake of fish containing n-3 long chain polyunsaturated fatty acids (LCPUFA) is important for adequate development.
Researchers based in Britain and Denmark set out to examine the effect of taking fish oil supplements during pregnancy on the growth and body composition of children later in life.
The trial involved 736 pregnant women who received either fish oil or olive oil daily from week 24 of pregnancy week until one week after birth.
Height, weight, head and waist measurements were assessed 11 times from birth to age six and adjusted for age and sex.
The findings, published in The British Medical Journal, revealed a sustained higher body mass index from 12 months old to six years of age.
At six years of age, DXA scans showed children whose mothers had taken fish oil supplements while pregnant had a 395g higher total mass, 280.7g higher lean mass, 10.3g higher bone mineral content and 116.3g higher fat mass compared with children of mothers who took the control oil.