TUESDAY, Oct. 19 (HealthDay News) -- Although some studies have
shown a benefit to mothers and their infants from taking
supplemental fish oil in the form of docosahexaenoic acid (DHA), a
new Australian study finds no such benefit.
In this large randomized, controlled study of more than 2,000
pregnant women, the researchers found no benefit from DHA in
reducing levels of postpartum depression or improving thinking
skills (cognitive) and language development in babies.
"Our data suggest that there is no need for apparently healthy pregnant women to take DHA supplements," said lead researcher Maria Makrides, from Women's and Children's Health Research Institute in Adelaide, Australia.
"Further work is needed to determine the potential benefits of DHA supplementation for women with a history or depression and for women at risk of having a premature baby," she added.
The report is published in the Oct. 20 issue of the
Journal of the American Medical Association.
For the study, Makrides and colleagues randomly assigned 2,399
women less than 21 weeks' pregnant to receive either daily fish oil
supplements containing 800 mg of DHA or vegetable oil capsules
containing no DHA. The women took these until the birth of their
The researchers used the Edinburgh Postnatal Depression Scale to
assess the mothers' levels of depression and the Bayley Scales of
Infant and Toddler Development to assess cognitive and language
development in their children.
During the first six months after delivery, there was no
clinically significant difference between the groups in the levels
of postpartum depression -- 9.67 percent among women receiving DHA
supplements and 11.19 percent among women receiving no DHA,
Makrides and colleagues found. In addition, there was no
significant difference between the groups in the number of new
cases of depression, they noted.
Among the children, at 18 months after birth, the researchers
found no difference in developmental scores between children whose
mothers had received DHA and those whose mothers had not.
There was also no difference in other developmental scores for
motor development and social-emotional behavior, the researchers
The study did find that significantly fewer infants from the DHA
group spent time in the neonatal intensive care unit, compared to
infants in the control group -- something that researchers
attributed to fewer preterm births in the DHA group. DHA
supplementation was associated with a "small to modest increase in
the duration of gestation," they reported.
One expert pointed to the DHA group's lower rate of preterm
birth as a substantial benefit, compared to that of the control
Dr. Emily Oken, an associate professor of medicine at Harvard
Medical School and author of an accompanying journal editorial,
said that "fish is the primary dietary source of DHA and other
omega-3 fatty acids, which are critical nutrients in pregnancy" for
brain and eye development.
Many women in the United States eat very little fish, and
therefore do not consume enough DHA, she added.
In her editorial, Oken charged that the Bayley scale used to
measure cognitive development of toddlers in the study was a poor
predictor of possible deficits that might not show up until
children are in preschool or elementary school.
She also noted that fish oil supplements "are safe, well
tolerated, and reduce risks for early preterm birth," which she
said is associated with maternal depression. She recommended that
pregnant women get the consensus dosage of 200 mg/day of DHA,
either by including low-mercury, high-DHA fish in their diets or by
taking a daily fish oil supplement.
"An important finding [in the trial] was that fish oil appears to be safe in pregnancy," Oken added.
Commenting on the study, Dr. Gene Burkett, professor of
obstetrics and gynecology at the University of Miami Miller School
of Medicine said "there has been an overuse of the omega-3 fatty
acids -- most of it came from nutrition people rather than from
solid medical studies."
Burkett said women should eat fish during pregnancy and the
concerns about harmful levels of mercury in fish can be gotten
around by eating fish with little mercury. "You can't replace fish
by using these supplements," he said.
A representative of the health supplements industry took issue
with the findings, however.
"Unfortunately in this trial, we have no idea of the DHA status of the mothers at the beginning of pregnancy or when they were evaluated for depression," Duffy MacKay, vice president of scientific & regulatory affairs at the Council for Responsible Nutrition, said in a news release.
"DHA status needs to be adequate
throughout pregnancy for women and their infants to receive
the many established benefits," he said, adding that "we [also]
have no idea of the DHA status of the infants at 18 months when
they were evaluated for neurocognitive outcomes. Without
measurements of DHA status, it is difficult to draw conclusions
from the study and certainly should not provide definitive advice
For more information on eating fish during pregnancy, visit the
U.S. Food and Drug Administration.
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