By Dailymail.Com Reporter
Pregnant women who eat a daily portion of oily fish or take supplements may protect their unborn child from high blood pressure, a new study found.
Studying obese children under the age of six, researchers found some did not experience the typical spike in systolic blood pressure and diastolic blood pressure.
Further research showed most of those children had mothers who’d taken DHA (docosahexaenoic acid, an omega-3 fatty acid) during pregnancy.
The best results were seen in children of women who’d taken 600 milligrams of DHA a day. DHA is found mostly in fish and seafood such as herring, oysters or roe.
Salmon has around 2,477mg per 6oz (170g) fillet, tuna 1940mg in a 6oz fillet, Atlantic cod 277mg per 6oz fillet
The findings are important as the prevalence of high blood pressure during childhood is on the rise, partly owing to the high rates of obesity during childhood.
Co-author Professor of Nutrition Susan Carlson at the University of Kansas explained: ‘Consumption of docosahexaenoic acid (DHA) and eicosapentaenoic acid from fish oil is well known to reduce blood pressure in both adults and children.
‘However, there has been recent interest in the potential programming association of DHA in utero and in early infancy with long-term physiological functions, including blood pressure.
‘An observational study from the Netherlands has linked higher intrauterine DHA exposure to lower childhood blood pressure.
‘However, the association of prenatal intake of DHA supplement with childhood blood pressure has not been evaluated in randomised clinical trials.’
The study enrolled pregnant women at the University of Kansas Medical Center’s Maternal and Child Nutrition and Development Lab between March 2006 and September 2009.
Half were given a placebo or a daily prenatal supplement of 600 milligrams DHA for a mean 14.5 weeks’ – all before 20 weeks – gestation until birth. The main aim of the study was to measure cognitive development while childhood blood pressure was a planned secondary outcome.
The study involved 171 children whose blood pressure was measured longitudinally at every six months from the age of four.
It found being overweight and obese were associated with the expected higher blood pressure in the placebo group but not in the group whose mothers were assigned to DHA.
Obese and overweight children of mothers in the placebo group had a large mean increase of 3.94 mm Hg for systolic BP and 4.97 mm Hg for diastolic blood pressure compared with overweight/obese children of DHA-supplemented mothers.
Dr Carlson said: ‘The increase in blood pressure among children who were obese or overweight in the placebo group compared with the DHA group was large (3.94 mm Hg for SBP vs 4.97 mm Hg for DBP) and statistically significant.
‘Although we knew that obesity or overweight condition is associated with higher blood pressure in adults and children, we did not hypothesise a priori that children who were overweight or obese as a group would gain an advantage from intrauterine exposure to DHA.
‘Prenatal DHA exposure appears to programme the developing foetus to be protected against the blood pressure-elevating effects of obesity in childhood.’
And lower blood pressure at six might extend beyond childhood.
Dr Carlson said: ‘It is known that blood pressure tracks over time such that people with higher blood pressure early in life are more likely to have higher blood pressure later in life.’
Co-author Professor of Psychology Carlson John Colombo added: ‘This research is aimed at expectant mothers and pediatricians who wonder what you can do prior to the birth of your child to optimize health and behavior outcomes
‘There’s a phenomenon called “developmental programming,” and researchers have studied effects of the prenatal environment on long-term outcomes since World War II.
‘The prenatal environment programmes a foetus’ metabolism for what to expect in the postnatal environment.
‘Part of DHA’s known effects may be in programming cardiac function that preserves normal blood pressure in the case of high postnatal weight gain.’
The study was published in JAMA Network Open.