May 2016 Issue
Omegas: Omega-3 Fats and Pregnancy — Health Benefits for Both Mom and Baby
By Clare Tone, MS, RD
Vol. 18 No. 5 P. 14
The health benefits of omega-3s are far ranging and well understood among health professionals and consumers alike. But less well known are specific benefits these fats provide pregnant women and their babies.
Mary Harris, PhD, RDN, a professor and dietetics program director at Colorado State University in Fort Collins, and Carol Lammi-Keefe PhD, RD, a professor at Louisiana State University in Baton Rouge, are two leading researchers on omega-3 fatty acids who presented their findings at the Academy of Nutrition and Dietetics' 2015 Food & Nutrition Conference & Expo®.1,2 Their work focuses on the benefits of omega-3s—specifically DHA—on moms and their infants. They're also passionate about how to help pregnant women break through barriers that keep them from achieving optimal levels of these important fats in their diet.
According to Harris and Lammi-Keefe, benefits for infants include improved vision and cognitive development, better sleeping patterns, and possibly improved distribution of fat adiposity. For moms, benefits include a more healthful gestation duration and a possible decrease in postpartum depression (PPD).1,2 However, partly due to the cost of seafood and misperceptions about mercury, pregnant women in the United States aren't meeting established requirements for seafood consumption.
Benefits for Baby
An early study published by Lammi-Keefe and colleagues in the journal Lipids measured improved visual acuity in 4-month-old infants whose mothers received a DHA-enriched functional food daily during pregnancy.3 A 2015 review article in the journal Nutrients looked at cognitive development in infants born to mothers consuming seafood throughout pregnancy compared with nonseafood eaters. Important insights included significantly improved language and social activity scores at 15 to 18 months of age. Researchers also observed a significant reduction in the number of children with suboptimal IQ and behavior scores, in some cases persisting up to age 8.4 Another study by Lammi-Keefe and colleagues measured significant gains in problem solving at 9 months of age among infants whose mothers ate a functional food containing 300 mg DHA during pregnancy compared with infants whose mothers received a placebo.5
Another benefit for baby—and by extension, mom as well—is sleep. While we think of sleep as a quality-of-life benefit, research shows that infants' sleep and wake cycles following delivery are highly correlated with later positive developmental outcomes. In a 2012 study published in Early Human Development, Lammi-Keefe and colleagues measured improved sleep/wake states in infants of mothers who consumed a functional food with 300 mg DHA daily during pregnancy compared with infants whose mothers received a placebo.6
A compelling area of emerging research suggests improved adiposity patterns in babies born to moms consuming more omega-3 DHA through diet compared with moms who had lower DHA intake during pregnancy. A 2011 study in the American Journal of Clinical Nutrition followed pregnant women and their unborn babies until those babies were 3 years old. Children of mothers who had higher concentrations of omega-3 fatty acids in their diet and in their umbilical cord plasma during pregnancy had lower fat adiposity.7 In contrast, a review article published in 2013 found that perinatal exposure to a diet high in omega-6 fatty acids results in a progressive accumulation of body fat across generations.8 However, omega-6 fatty acids have been associated with positive health outcomes, and more research is needed before recommendations can be made regarding limiting omega-6 fatty acids.
Benefits for Mom
In a 2015 study published in BioMed Research International, Harris and colleagues showed DHA supplementation can increase the gestation period by four days. They observed a longer gestation period in the study group who received education about increasing DHA intake by 300 mg per day through fish and other dietary sources.9 While these benefits translate to mom in terms of a healthier pregnancy, they also may provide benefits for the baby. Harris and colleagues refer to research showing that shorter gestation time is associated with greater risk of ADHD in school-age children, so even a four-day increase in gestation time can translate to reduced risk of ADHD later in life.9 Indeed, this finding was discussed in the 2015 review article citing oily fish consumption more than once per week correlated with a decreased risk of hyperactivity compared with women who ate no fish during early and late pregnancy.4
The role of omega-3 fats in mental health is a major focus of contemporary research, and the question of whether DHA may be protective against PPD is picking up traction. It's estimated that between 5% and 15% of childbearing women experience PPD, and women who are breast-feeding often express reluctance to receive medical treatment. In 2014, Lammi-Keefe and colleagues published results of a double-blind, placebo-controlled pilot study that investigated this question. Forty-two pregnant women were randomly assigned to receive either corn oil placebo capsules or 300 mg DHA capsules from 24 to 40 weeks gestation. Women were screened for PPD during pregnancy and up to six months following delivery. Mothers who received DHA had fewer symptoms of PPD compared with those who received the placebo, and researchers called for further large-scale investigations of this important topic.10
Daily Requirements and Best Sources
The 2015–2020 Dietary Guidelines for Americans recommend two to three servings of seafood per week for women who are pregnant (the equivalent of 8 to 12 oz weekly). This is equivalent to 200 to 2,400 mg EPA and DHA per day depending on the type of seafood eaten.11 According to Harris, 300 mg of DHA per day is considered a good threshold level for pregnant women given the inefficient conversion of plant sources of omega-3 fats to DHA in humans. "Three ounces of salmon has 1,000 mg, so if you're eating salmon you're getting a whole day's supply," Harris says.
Certain types of omega-3 fats from plant foods like walnuts and flax can be converted to DHA, but it's believed that the body's need for DHA during late pregnancy and early infancy outpaces the body's ability to make it. "Plant sources of omega-3 fatty acids have the shorter chain omega-3 fatty acids, not the longer chain. It is the longer chain omega-3 fatty acids, such as DHA, that are biologically and physiologically active and therefore important to human health. As humans, we aren't good at converting the shorter chain omega-3 fatty acids from plant sources to the long chain fatty acid DHA," Lammi-Keefe says.
"Obviously, vegans have perfectly healthy babies; so you can convert, but the conversion in adults is less than 1%—and a little higher in pregnant women—so that's a lot of flax and a lot of walnuts," Harris adds.
High-DHA eggs are another important food source. A typical egg contains about 16 mg DHA while the high-DHA eggs range from 150 to 165 mg. Then there are fish oil supplements, but Harris and other researchers encourage consumption of whole food sources of DHA rather than supplements because studies using fish oil capsules haven't consistently provided the same benefits. "My message to women is eat fish twice per week because it's high in DHA, but it also has other nutrients like iron, selenium, and important amino acids. It's the synergistic effect of the unique nutrient bundle," Harris says.
Questions About Mercury
Much discussion and research has focused on whether mercury in seafood poses a risk to pregnant women and infants. According to Harris and Lammi-Keefe, benefits of seafood intake at recommended levels outweigh the risks of potential hazards, including mercury. When developing the guidelines for fish intake for pregnant women, the 2015 Dietary Guidelines Advisory Committee relied on the cost-benefit analysis developed by the United Nations Food and Agriculture Organization and the World Health Organization. They concluded that the neurodevelopmental benefits of DHA in fish outweigh the potential risks of not eating fish.12
According to Harris, "The key is to eat a variety of fish and only avoid those four high in methyl-mercury: shark, swordfish, tilefish, and king mackerel. Those other nutrients in fish like selenium may actually decrease the ability to absorb mercury."
Helping Pregnant Clients Meet DHA Goals
Despite the health benefits of eating fish, most American women don't come close to getting the recommended amount of DHA in their diet. "If we could get women to eat more servings of high-DHA foods that would be a miracle," Harris says. "Currently, they're eating less than 2 oz [per day]." Concerns about mercury are one barrier, but, according to focus groups conducted by Harris' team, other obstacles include perceptions about cost, lack of familiarity with foods—especially DHA-rich eggs—and aversion to smells and tastes while pregnant.
In response, Harris and her team developed a targeted intervention program to increase DHA intake among pregnant women. The program was introduced to a Special Supplemental Nutrition Program for WIC in Denver. The intervention included targeted education including behavior change strategies, and shopping lists and recipes.13 "[Currently], some WICs across the country have included the high-DHA eggs. And the WIC package for breast-feeding moms does include 12 oz of tuna or mackerel or salmon. But it's not in the pregnancy package; it's only in the breast-feeding package. We would like to see it in the pregnancy package, too."
Lammi-Keefe says, "Many of us grew up with the adage that 'fish is brain food.' Today, we have the evidence that explains this saying."
— Clare Tone, MS, RD, is a freelance writer, high-altitude gardener, and nutrition instructor at Metropolitan State University of Denver.
Crunchy Walnut-Crusted Salmon Fillets
11/2 cups California walnuts
3 T dry breadcrumbs
3 T lemon rind, finely grated
11/2 T extra-virgin olive oil
3 T fresh dill, chopped
Salt and pepper to taste
6 3-oz salmon fillets, skin on
2 T fresh lemon juice
- Place walnuts in food processor; coarsely chop. Add breadcrumbs, lemon rind, olive oil, and dill; pulse until crumbly. Mixture should stick together. Season with salt and pepper, to taste; set aside.
- Arrange salmon fillets skin side down on parchment paper–lined baking sheets. Brush tops with mustard.
- Spoon 1/3 cup of walnut crumb mixture over each fillet; gently press the crumb mixture onto the surface of the fish. Cover with plastic wrap; refrigerate for up to 2 hours.
- Bake at 350° F for 15 to 20 minutes, or until salmon flakes with a fork. Just before serving, sprinkle each with 1 teaspoon lemon juice.
Calories: 360; Total fat: 26 g; Sat fat: 3 g; Monounsaturated fat: 7 g; Polyunsaturated fat: 15 g; Cholesterol: 62 mg; Sodium: 90 mg; Carbohydrates: 7 g; Dietary fiber: 3 g; Protein: 24 g
— Recipe courtesy of The California Walnut Board.
1. Harris MA. Implementation of evidence based recommendations for omega 3 docosahexaenoic acid (DHA) in pregnancy. Talk presented at: Academy of Nutrition and Dietetics 2015 Food and Nutrition Conference & Expo; October 5, 2015; Nashville, TN. http://files.abstractsonline.com/CTRL/77/9/E3E/4BF/5D2/428/AA9/041/DB1/275/993/
A4/a1799_1.pdf. Accessed February 8, 2016.
2. Lammi-Keefe CJ. Nutrition's role in successful pregnancy outcome: omega-3 fatty acids. Talk presented at: Academy of Nutrition and Dietetics 2015 Food and Nutrition Conference & Expo; October 5, 2015; Nashville, TN. http://files.abstractsonline.com/CTRL/E8/E/FB2/
17E/BBD/4EC/2BB/9E6/6DA/C74/2AB/CE/a1794_1.pdf. Accessed February 8, 2016.
3. Judge MP, Harel O, Lammi-Keefe CJ. A docosahexaenoic acid-functional food during pregnancy benefits infant visual acuity at four but not six months. Lipids. 2007;42(2):117-122.
4. Starling P, Charlton K, Mcmahon AT, Lucas C. Fish intake during pregnancy and foetal neurodevelopment — a systematic review of the evidence. Nutrients. 2015;7(3):2001-2014.
5. Judge MP, Harel O, Lammi-Keefe CJ. Maternal consumption of a docosahexaenoic acid-containing functional food during pregnancy: benefit for infant performance on problem-solving but not on recognition memory tasks at age 9 mo. Am J Clin Nutr. 2007;85(6):1572-1577.
6. Judge MP, Cong X, Harel O, Courville AB, Lammi-Keefe CJ. Maternal consumption of a DHA-containing functional food benefits infant sleep patterning: an early neurodevelopmental measure. Early Hum Dev. 2012;88(7):531-537.
7. Donahue SM, Rifas-Shiman SL, Gold DR, Jouni ZE, Gillman MW, Oken E. Prenatal fatty acid status and child adiposity at age 3 y: results from US pregnancy cohort. Am J Clin Nutr. 2011;93(4):780-788.
8. Muhlhausler BS, Ailhaud GP. Omega-6 polyunsaturated fatty acids and the early origins of obesity. Curr Opin Endocrinol Diabetes Obes. 2013;20(1):56-61.
9. Harris MA, Reece MS, McGregor JA, et al. The effect of omega-3 docosahexaenoic acid supplementation on gestational length: randomized trial of supplementation compared to nutrition education for increasing n-3 intake from foods. Biomed Res Int. 2015;2015:123078.
10. Judge MP, Beck CT, Durham H, McKelvey MM, Lammi-Keefe CJ. Pilot trial evaluating maternal docosahexaenoic acid consumption during pregnancy: decreased post-partum depressive symptomology. Int J Nurs Sci. 2014;1(4):339-345.
11. US Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans 2015–2020: Eighth Edition. http://health.gov/dietaryguidelines/2015/guidelines/chapter-1/a-closer-look-inside-healthy-eating-patterns/#callout-seafood. Accessed March 2, 2016.
12. US Department of Agriculture, US Department of Health and Human Services. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. http://health.gov/dietaryguidelines/2015-scientific-report/14-appendix-E2/e2-38.asp. Accessed February 29, 2016.
13. Troxell H, Anderson J, Auld G, et al. Omega-3 for baby and me: material development for a WIC intervention to increase DHA intake during pregnancy. Matern Child Health J. 2005;9(2):189-197.