In a new trial, pregnant women who consumed a daily 600-milligram supplement of DHA (docosahexaenoic acid), an omega-3 fatty acid, had children who appeared to be protected from the blood pressure-elevating effects of excessive weight in early childhood.
DHA is a major structural fat found in high amounts in the brain and eyes. It can be consumed naturally by eating fatty fish, such as anchovies, salmon, and tuna, but due to potential mercury levels, fish consumption is often limited during pregnancy.
“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,” said co-author Dr. John Colombo, University of Kansas (KU) professor of psychology, director of KU’s Life Span Institute and currently KU’s interim vice chancellor for research.
“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 programs a fetus’ 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 prevalence of high blood pressure, or hypertension, among children as reported by various studies ranges from 5.4 percent to 19.4 percent. If left untreated, high blood pressure in children can damage the brain, heart, kidneys, and eyes.
For the study, KU researchers evaluated women with low-risk pregnancies in the Kansas City area between March 2006 and September 2009. Half were randomly assigned to a daily prenatal supplement of 600 milligrams DHA, and half were given a placebo. In 171 children, blood pressure was measured 5 times between the ages of 4 and 6.
The key finding was that being overweight and obese were linked to the expected higher blood pressure in the placebo group but not in the group whose mothers had been taking DHA supplements.
While many prenatal supplements in the U.S. contain DHA, most have much less than 600 milligrams, the daily amount used in the study. The researchers emphasize that the minimal amount of prenatal DHA needed to protect against the rise in blood pressure in children with excessive weight is not known.
“Prenatal DHA exposure appears to program the developing fetus to be protected against the blood pressure-elevating effects of obesity in childhood,” said co-author Dr. Susan Carlson, AJ Rice Professor of Nutrition in the KU Department of Dietetics and Nutrition at the KU Medical Center.
The researchers believe lower blood pressure at age 6 might extend beyond childhood. “It is known that blood pressure tracks over time such that people with higher BP early in life are more likely to have higher BP later in life,” Carlson said.
Previous reports of the trial, published in JAMA Network Open, also show that maternal DHA supplementation reduced birth before 34 weeks’ gestation and was associated with higher fat-free body mass at age 5.
Source: University of Kansas