The amounts and relative proportions of omega-3 and omega-6 fats in people's diets affect myriad aspects of health.
And two new clinical trials suggest that a mother's omega-3/6 intake balance can impact her child's birth date and weight … while influencing body composition at age six.
Sadly, most Americans consume omega-6 fats to unhealthful excess. Most omega-6s come from cheap vegetable oils – corn, soy, safflower, sunflower, and cottonseed – and the packaged/prepared foods made with them.
(Olive oil, macadamia nut oil, hi-oleic sunflower oil, and canola oil are much lower in omega-6s and make healthier choices.)
Clinical trial links omega-3 DHA to healthier birth weight
Last month, University of Kansas (KU) researchers report that the infants of mothers who were given omega-3 DHA during pregnancy enjoyed substantial benefits.
The results stem from the first five years of a 10-year, double-blind randomized controlled trial (Carlson SE et al. 2013).
Omega-3s in child development
Along with EPA, the essential fatty acid known as DHA is one of the two major omega-3s in fish oil and human cells.
The highest DHA levels occur in brain cells, and DHA is proven essential to infants' brain and eye development.
An infant obtains DHA from his or her mother in utero and from breast milk, but the amount depends on the mother's own DHA blood levels.
American women typically consume less DHA than women in most of the developed world, due in part to low fish intake.
The sole food sources of DHA are fish and shellfish … especially fatty fish like salmon, sardines, mackerel, tuna, and sablefish.
Prior research has proven the benefits of infant's DHA intake on their cognitive and intellectual development … but DHA is accumulated most rapidly in the growing brain during pregnancy.
As KU's Dr. Colombo said, “That's why we are so interested in the effects of DHA taken prenatally, because we will really be able to see how this nutrient affects development over the long term.”
During the study, 350 women took placebo or DHA capsules, starting from before 20 weeks of gestation through birth.
The average omega-3 DHA intake for the mothers in the omega-3 group was 469 mg per day … which raised their own DHA blood levels and the DHA levels in their umbilical cord blood.
On average, the babies born to mothers taking omega-3 DHA showed six advantages:
Heavier by six ounces.
Longer by 0.7 centimeters.
Gestated for three additional days.
Larger heads, by 0.5 centimeters of circumference
Less likely to be born sooner than 34 weeks of gestation.
If born preterm, they had shorter hospital stays than preterm babies in the placebo group.
As the authors wrote, “A reduction in early preterm and very-low birth weight could be important clinical and public health outcomes of DHA supplementation.” (Carlson SE et al. 2013)
The Kansas team will follow the infants for another five years, to see whether prenatal DHA supplements can benefit children's intelligence scores and school readiness.
“A reduction in early preterm and very low birth weight delivery could have clear clinical and public health significance,” said Susan Carlson, Ph.D., of KU's Department of Dietetics and Nutrition. She co-directed the study with John Colombo, Ph.D., of KU's Life Span Institute.
“We believe that supplementing U.S. women with [omega-3] DHA could safely increase mean [average] birth weight and gestational age to numbers that are closer to other developed countries such as Norway and Australia,” said Carlson.
During the first five years of the study, children of women enrolled in the study received multiple developmental assessments at regular intervals throughout infancy and at 18 months of age.
The children will receive twice-yearly assessments until they are six years old, to measure developmental milestones linked to lifelong health outcomes.
The study is funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Mothers' high omega-6 levels linked to kids' excess weight at age six
Coincidentally, in January of 2013, British researchers reported that expectant mothers' intake of omega-3 and omega-6 fats affects their children's weight at age six.
The clinical trial – led by Dr. Nicholas Harvey of the UK's University of Southampton – involved 293 mother-child pairs participating in the Southampton Women's Survey (Moon RJ et al. 2013).
“Obesity is a rising problem in this country and there have been very few studies of mothers' fatty acid levels during pregnancy and offspring fat mass,” said Harvey.
First, the UK team measured the fat and muscle mass of the boys and girls at four and six years.
Then, they compared those measurements to the levels of omega-3 and omega-6 fatty acids in blood collected from the mothers during pregnancy.
The comparison showed that, on average, children's weight at age six was affected by their mothers' intake of omega-3 and omega-6 fatty acids:
Children born to women who had higher-than-average blood levels of omega-3s during pregnancy had less body fat and more muscle and bone.
Children born to women who had higher-than-average blood levels of omega-6s during pregnancy had more body fat and less muscle and bone.
“This work should help us to design interventions aimed at optimizing body composition in childhood and later adulthood and thus improve the health of future generations,” added Professor Cyrus Cooper, also of University of Southampton (UOS 2013).
“These results suggest that alterations to maternal diet during pregnancy to reduce omega-6 intake might have a beneficial effect on the body composition of the developing child.”
Limiting the intake of omega-6 fats – plus boosting the intake of omega-3s – during pregnancy could lead to healthier babies with less fat and more muscle, say the UK team.
Study co-author Rebecca Moon, M.D., made this key comment:
“Omega-6 and omega-3 fatty acids seem to act in opposite directions on fat mass; previous trials have attempted to use omega-3 supplementation to reduce fat mass, but our results suggest that such an approach might work best when combined with a reduction in dietary omega-6 intake.” (UOS 2013)
“This work should help us to design interventions aimed at optimizing body composition in childhood and later adulthood and thus improve the health of future generations,” added co-author Cyrus Cooper (UOS 2013).
- Carlson SE, Colombo J, Gajewski BJ, Gustafson KM, Mundy D, Yeast J, Georgieff MK, Markley LA, Kerling EH, Shaddy DJ. DHA supplementation and pregnancy outcomes. Am J Clin Nutr. 2013 Feb 20. [Epub ahead of print]
- Larqué E, Gil-Sánchez A, Prieto-Sánchez MT, Koletzko B. Omega 3 fatty acids, gestation and pregnancy outcomes. Br J Nutr. 2012 Jun;107 Suppl 2:S77-84. doi: 10.1017/S0007114512001481. Review.
- Moon RJ, Harvey NC, Robinson SM, Ntani G, Davies JH, Inskip HM, Godfrey KM, Dennison EM, Calder PC, Cooper C; SWS Study Group. Maternal plasma polyunsaturated fatty acid status in late pregnancy is associated with offspring body composition in childhood. J Clin Endocrinol Metab. 2013 Jan;98(1):299-307. doi: 10.1210/jc.2012-2482. Epub 2012 Nov 16.
- Robinson DT, Carlson SE, Murthy K, Frost B, Li S, Caplan M. Docosahexaenoic and arachidonic acid levels in extremely low birth weight infants with prolonged exposure to intravenous lipids. J Pediatr. 2013 Jan;162(1):56-61. doi: 10.1016/j.jpeds.2012.06.045. Epub 2012 Aug 9.
- Skilton MR, Mikkilä V, Würtz P, Ala-Korpela M, Sim KA, Soininen P, Kangas AJ, Viikari JS, Juonala M, Laitinen T, Lehtimäki T, Taittonen L, Kähönen M, Celermajer DS, Raitakari OT. Fetal growth, omega-3 (n-3) fatty acids, and progression of subclinical atherosclerosis: preventing fetal origins of disease? The Cardiovascular Risk in Young Finns Study. Am J Clin Nutr. 2013 Jan;97(1):58-65. doi: 10.3945/ajcn.112.044198. Epub 2012 Nov 14.
- University of Kansas (KU). Prenatal DHA reduces early preterm birth, low birth weight. February 25, 2013. Accessed at http://www.news.ku.edu/2013/02/25/prenatal-dha-reduces-early-preterm-birth-low-weight-birth-weight
- University of Southampton (UOS). Limiting polyunsaturated fatty acid levels in pregnancy may influence body fat of children. January 10, 2013. Accessed at http://www.southampton.ac.uk/mediacentre/news/2013/jan/13_06.shtml