Research finds consuming walnuts during pregnancy significantly improved child neurodevelopmental outcomes at age two

Optimal nutrition is critical during pregnancy for both mother and child, especially for brain development and healthy birth weight. Lack of key nutrients increases the risk for low birth weight and developmental delays in children. According to the joint UNICEF and WHO study of global, regional, and country estimates of low birth weight, the incidence of LBW in the Middle East and the Gulf countries was reported as Oman (9%), Lebanon (6%), Syria (6%), Algeria (7%), Kuwait (7%), Libya (7%), Tunisia (7%), Bahrain (8%), Jordan (10%), Qatar (10%), Morocco (11%), Saudi Arabia (11%), Egypt (12%), and Yemen (32%). ¹

In a randomized controlled trial  published in JAMA Network Open, and supported by the California Walnut Commission, researchers found incorporating walnuts and olive oil, in addition to following the Mediterranean Diet during pregnancy, improved child neurodevelopmental outcomes at age two, compared to those who mothers didn’t follow the diet during pregnancy. ²

The study, conducted in Spain, followed 1,221 pregnant women (19 to 23 weeks’ gestation) at high risk of delivering newborns who were small for gestational age were randomly divided into three groups:  

• a Mediterranean diet group that included 450 grams of walnuts and two liters of free extra virgin olive oil every month   
• a mindfulness-based stress reduction group  
• or usual care  

Among the 626 children born and eligible for the study, neurodevelopment scores at two years old were significantly higher in the cognitive and social-emotional domains in the Mediterranean diet group receiving walnuts and olive oil compared with children from the usual care group.  

Dr. Dietician and Psychologist Pırıl Şenol said; “Walnut consumption during pregnancy has been posited as potentially beneficial due to its rich nutrient profile, notably comprising omega-3 fatty acids, protein, vitamins, and minerals essential for maternal health and fetal development. Omega-3 fatty acids, such as alpha-linolenic acid (ALA), are particularly crucial as they play integral roles in neurological and visual development of the fetus. Furthermore, walnuts offer a source of plant-based protein and various micronutrients, contributing to overall nutritional adequacy during gestation.

While direct empirical evidence specifically linking walnut consumption to the prevention of low gestational weight babies remains limited, the broader nutritional benefits of nuts, including walnuts, are recognized in supporting maternal health outcomes. Adequate maternal nutrition is pivotal in ensuring optimal fetal growth and development, potentially influencing birth weight outcomes. Therefore, integrating walnuts into a balanced diet during pregnancy may be advantageous, albeit specific recommendations should be guided by healthcare providers, considering individual dietary needs and health circumstances”^3-4.

This study adds to the more than 300 additional publications that have explored the role a Mediterranean diet including tree nuts, primarily walnuts (PREDIMED study), on health outcomes such as cognitive function, blood pressure, total cholesterol, and fasting blood sugar.  

For people across all lifespans, walnuts provide a host of important nutrients and phytochemicals, they also provide a notable amount of plant protein at 4 grams per ounce (12-14 halves), contribute to the daily intake of fiber (4 grams) and are a good source for magnesium (45 milligrams).⁵ Walnuts can play an important role in everyone’s daily eating pattern. They are the only tree nut that provide an excellent source of the plant-based omega-3 alpha-linolenic acid (2.5g/oz), which research indicates may play a role in heart health, brain health and healthy aging.^6-10

The interventions within the study were time intensive and may not be applicable for some pregnant individuals. These results need replication in further randomized clinical trials.

Here are a few key tips to put this research into practice:  

• Put plant-based foods like fruits and vegetables, whole grains, legumes, nuts and seeds at the center of your plate and the focus of your meal-planning.  
• Mix up your salads to keep them interesting, incorporating a variety of protein sources along with colorful produce, fresh herbs and fruits for flavor, and good fats like toasted walnuts for texture and a drizzle of olive oil to top it off.  
• Enhance your meals with walnuts, like Toasted Walnut Asian Chicken and Vegetables and Walnut Spinach Chicken Masala Find more inspiration on incorporating California walnuts and other delicious Mediterranean recipes.

References:

1. Zainab Taha, Ahmed Ali Hassan, Factors associated with preterm birth and low birth weight in Abu Dhabi, UAE, Int. J. Environ. Res. Public Health, 2020
2. Crovetto F, Nakaki A, Arranz A, et al. Effect of a Mediterranean Diet or mindfulness-based stress reduction during pregnancy on child neurodevelopment: A prespecified analysis of the IMPACT BCN randomized clinical trial. JAMA Netw Open. 2023;6(8):e2330255.
3. Tahaei  H, Gignac  F, Pinar  A,  et al.  Omega-3 fatty acid intake during pregnancy and child neuropsychological development: a multi-centre population-based birth cohort study in Spain.  Nutrients. 2022;14(3):518. doi:3390/nu14030518
4. Ogundipe  E, Tusor  N, Wang  Y, Johnson  MR, Edwards  AD, Crawford  MA.  Randomized controlled trial of brain specific fatty acid supplementation in pregnant women increases brain volumes on MRI scans of their newborn infants.  Prostaglandins Leukot Essent Fatty Acids. 2018;138:6-13. doi:1016/j.plefa.2018.09.001
5. S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019. fdc.nal.usda.gov.
6. Fleming JA, Kris-Etherton PM. The evidence for α-linolenic acid and cardiovascular disease benefits: comparisons with eicosapentaenoic acid and docosahexaenoic acid. Adv Nutr. 2014;5(6):863S-76S. doi.org/10.3945/an.114.005850.
7. Sala-Vila A, Fleming J, Kris-Etherton P, Ros E. Impact of alpha-linolenic acid, the vegetable omega-3 fatty acid, on cardiovascular disease and cognition [published ahead of print February 16, 2022]. Advances in Nutrition. doi.org/10.1093/advances/nmac016.
8. Naghshi S, Aune D, Beyene J, et al. Dietary intake and biomarkers of alpha linolenic acid and risk of all cause, cardiovascular, and cancer mortality: Systematic review and dose-response meta-analysis of cohort studies. BMJ. 2021;375:n2213. doi:10.1136/bmj.n2213.
9. Barceló-Coblijn G, Murphy EJ. Alpha-linolenic acid and its conversion to longer chain n3 fatty acids: Benefits for human health and a role in maintaining tissue n-3 fatty acid levels. Prog Lipid Res. 2009;48(6):355-74. doi.org/10.1016/j.plipres.2009.07.002.
10. Sala-Vila A, Guasch-Ferré M, Hu FB, et al. Dietary α-linolenic acid, marine ω-3 fatty acids, and mortality in a population with high fish consumption: Findings from the PREvención con DIeta MEDiterránea (PREDIMED) study. J Am Heart Assoc. 2016;5(1):e002543. doi.org/10.1161/JAHA.