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Babies See No Omega-3 Brain Gains
10/21/2010
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by Craig Weatherby


Australian researchers detected no brain-development advantages in babies born to nearly 2,400 mothers who took a very substantial daily dose of omega-3 DHA (800 mg).
 
Nor did the Aussie team find lower levels of post-partum depression in mothers taking omega-3 DHA.

Key Points
  • Tests infants took at 18 months detected no brain development benefits in those born to mothers who took 800mg of omega-3 DHA daily from gestation week 21 to birth.
  • The brain function test used cannot predict the mental advantages seen at four years or later in other clinical trials of maternal fish oil supplements.
  • The wisdom of higher maternal (and infant) fish and DHA consumption is supported by some clinical evidence and by reams of mutually reinforcing cell, animal, and population research.
  • Average American women and children do not get the recommended amounts of omega-3s.
  • Higher maternal fish intake may be a better fetal brain-booster, compared with taking omega-3 fish oil supplements during pregnancy.
  • Other clinical evidence indicates that omega-3s may reduce post-partum depression risk; varying outcomes suggest efficacy is influenced by unknown factors.
The authors noted that their findings contradicted the results of some other clinical trials... and the findings of most large-scale epidemiological studies, which link higher maternal fish intake to better brain performance in infants, toddlers, or children.
 
By way of explanation, they made two important observations:

“It may be that even well-conducted epidemiological studies overestimate [the benefits of fish and their omega-3s] …or that other nutrients in fish and seafood, beyond DHA, contribute to the observations from epidemiological studies” (Makrides M et al. 2010).

As we'll see, there are other compelling explanations for this apparent failure of mothers' omega-3 DHA supplements to improve their infants' mental performance at the age of 18 months.
 
These reasons include prior clinical trials in which the brain benefits of higher maternal omega-3 intakes were first detected at age four or older... and the known inability of the brain test used in the new trial to predict brain performance past the toddler years.
 
Coincidentally, Vital Choice founder Randy Hartnell is attending the Hawaii Seafood Symposium (October 20-22), whose theme is “Making Sense of Seafood Health Benefits and Risks.”
 
We'll bring you reactions to this new study from experts at the conference, who include Captain Joseph R. Hibbeln, M.D., of NIH, who co-authored the 2007 ALSPAC study... a joint US-UK project that provided extraordinarily strong evidence of the safety and brain benefits of high maternal fish intake.
 
Overall evidence favors maternal diets rich in omega-3s and fish
The outcomes of this Australian clinical trial may, at first blush, seem surprising.
 
However, most of the experts quoted in news reports agreed that there's ample, mutually reinforcing lab, animal, and epidemiological evidence indicating that it’s wise for expectant mothersand growing infants and childrento get plenty of fatty fish and/or fish oil.
 
For more information, see our Healthy Mom & Baby” page and the “Omega-3s and Child Development” section of our news archive.
 
Some of the most important research was reported in these articles from past issues of Vital Choices:
Sadly, the evidence shows that woman and children do not get the recommended amounts of omega-3s.
 
Shortage of omega-3s seen as common in women and children
Consensus guidelines call for women to consume an average of 200mg of DHA daily during pregnancy (Koletzko B et al. 2007).
 
Fish oil and human cell membranes contain two essential omega-3 fatty acids, called DHA and EPA.
 
Omega-3 DHA is essential for fetal brain and eye development and to optimal thinking and seeing through childhood and beyond.
 
This, among other reasons, explains why it makes sense to nurture babies on (DHA-rich) breast milk whenever possible… and why some infant formulas are fortified with DHA.
 
But most women in the United States and many other countries eat little fishand take no omega-3 supplementsand therefore do not get nearly enough omega-3 DHA.
 
For instance, in the 1999-2002 National Health and Nutrition Examination Survey, average DHA intake among pregnant women was only 73 mg per day (Nesheim M et al. 2007).
 
And a recent study in Canadian children found a shortage of omega-3 fatty acids that underscores a similar shortfall in the diets of American kids (see “Kids in US and Canada Deemed Omega-3 Deficient”).
 
New findings raise key questions: Fish or omega-3s?
The Australians’ report in The Journal of the American Medical Association (JAMA) starts by placing their negative findings in the context of generally positive evidence in favor of fishespecially but not exclusively fatty kindsor supplemental omega-3 DHA.
 
“Epidemiological investigations from the United States and Europe demonstrate that higher intakes of [omega-3s] from fish and seafood during pregnancy are associated with a reduced risk of depressive symptoms… as well as improved developmental outcomes in the offspring” (Makrides M et al. 2010).
 
The outcomes of the Australian clinical trialcalled DOMInO (DHA to Optimize Mother Infant Outcome)don’t change the overall evidence very much, and leave many important questions unanswered... for reasons enumerated by experts and explored below.
 
First, we’ll describe the study, which was led by Dr. Maria Makrides of the University of Adelaide.
 
Last year, her team published the positive results of a controlled clinical trial that found improved brain-development scores in preterm girls who were fed a high-DHA formula (Makrides M et al. 2009).
 
As Dr. Makrides’ team wrote then, the majority of DHA transferred from mother to fetus is moved across the placenta relatively late in a normal pregnancy, making dietary DHA especially beneficial for preterm infants.
 
Aussie clinical trial finds no infant-brain or maternal-mood benefits
Dr. Makrides’ DOMInO study was a double-blind, randomized controlled trial involving 2,399 pregnant women.
 
The women started the study when they were at 21 weeks’ gestation or less, and none had been taking any fish oil or other DHA supplements prior to the study.
 
The participants were randomly assigned to take one of two capsules of similar size, shape, and color daily until birth of their child:
  • DHA GroupThree 500mg fish oil capsules providing 800mg of DHA and 100 mg of EPA daily.
  • Control GroupThree 500 mg vegetable oil capsules without any DHA, daily.
The authors noted that the DHA dose (800 mg) falls above the estimated daily intake associated with lower risk of post-partum depression and higher scores on infant brain-development tests.
 
The vegetable oil capsules contained equal proportions of non-GMO canola, sunflower, and palm oil, matching the average Australian’s fatty-acid-intake profile.
 
At 18 months, key aspects of cognitive development were measured in the infants born to both groups, using a common infant brain-development test called the Bayley Scales.
 
The results showed no cognitive or language development advantages in the DHA group’s infants.
 
Why does DHA yield mixed results, versus positive associations with fish?
About half of all the trials testing DHA-fortified infant formulas also had negative outcomes (i.e., no brain advantages)… but most epidemiological studies associate greater fish consumption during pregnancy with improved infant development and cognitive function in older children (Oken E, Belfort MB 2010).
 
Commenting on the Australian report, omega-3 and child-development researcher Emily Oken, M.D., MPH, of Harvard Medical School suggested that these discrepancies might be explained by either of two possibilities:
  1. Fish is better for development, compared with supplemental omega-3 DHA.
  2. The epidemiological evidencemost of which links higher maternal consumption of fish (and its DHA) to better child outcomesis inherently unreliable.
As to the first possibility, Dr. Oken wrote, “It may be that the omega-3s in fish are more bioactive or that other beneficial nutrients within fish, such as selenium, vitamin D, and iodine, are also important.”
 
And she made two key points concerning the limitations of the generally well-designed Aussie study:
  • It is also possible that the Bayley scales are not sufficiently sensitive [and] might not detect relatively small but important differences in cognition or the [beneficial] effects of omega-3s on specific processes, such as memory, attention, and problem-solving, which have been demonstrated both in animal models and in humans.
  • “Also, the Bayley scales are poor predictors of higher level cognitive functions that do not mature until preschool or school age. A previous smaller study of maternal cod liver oil supplementation found measurable cognitive benefits at age 4 years, but none in infancy.”
Dr. Oken also pointed out that a recent trial conducted by the same Aussie team found improved Bayley scores in preterm girls who were fed a high-DHA formula (Makrides M et al. 2009).
 
As she wrote in JAMA, “For now, pregnant women should take care to get the recommended intake of 200 mg/day of DHA, either by including low-mercury, high-DHA fish in their diets or by taking a daily n-3 PUFA [omega-3] supplement” (Oken E, Belfort MB 2010).
 
Claims that omega-3s can make kids substantially smarter, all other influences aside, never had any basis in evidence.
 
But a preponderance of the evidence indicates that fish and omega-3s benefit growing brains and eyes… and suggests that higher DHA intake from conception on may yield optimal development as children reach age four and older.
 
And a flood of new findings on the lifelong impacts of infant nutrition suggests that the influences exerted by a child’s early DHA intake may establish persistent health patterns.
 
 
Sources
  • Golding J, Steer C, Emmett P, Davis JM, Hibbeln JR. High levels of depressive symptoms in pregnancy with low omega-3 fatty acid intake from fish. Epidemiology. 2009;20(4):598-603.
  • Hibbeln JR, Davis JM, Steer C; et al. Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study. Lancet. 2007;369(9561):578-585.
  • Koletzko B, Cetin I, Brenna JT, et al. Dietary fat intakes for pregnant and lactating women. Br J Nutr. 2007;98(5):873-877.
  • Makrides M et al. Effect of DHA Supplementation During Pregnancy on Maternal Depression and Neurodevelopment of Young Children: A Randomized Controlled Trial. JAMA. 2010;304(15):1675-1683. doi:10.1001/jama.2010.1507
  • Makrides M et al. Neurodevelopmental outcomes of preterm infants fed high-dose docosahexaenoic acid: a randomized controlled trial. JAMA. 2009;301(2):175-182.
  • Nesheim M, ed, Yaktine A, ed. Seafood Choices: Balancing Benefits and Risks. Washington, DC: National Academies Press; 2007. 
  • Oken E, Belfort MB. Fish, Fish Oil, and Pregnancy. JAMA. 2010;304(15):1717-1718. doi:10.1001/jama.2010.1541
  • Oken E, Østerdal ML, Gillman MW, et al. Associations of maternal fish intake during pregnancy and breastfeeding duration with attainment of developmental milestones in early childhood: a study from the Danish National Birth Cohort. Am J Clin Nutr. 2008;88(3):789-796.
  • Oken E, Radesky JS, Wright RO, et al. Maternal fish intake during pregnancy, blood mercury levels, and child cognition at age 3 years in a US cohort. Am J Epidemiol. 2008;167(10):1171-1181.
  • Oken E, Radesky JS, Wright RO, et al. Maternal fish intake during pregnancy, blood mercury levels, and child cognition at age 3 years in a US cohort. Am J Epidemiol. 2008;167(10):1171-1181.

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