Omega 3 pregnancy: fish oil helps children’s immune system

During the third trimester, expectant mothers should eat at least 2 servings of salmon each week, fatty fish rich in Omega 3, to improve the immune system activity of their children. This suggestion comes from the American Journal of Clinical Nutrition, which published results from a group of scientists led by Paul Noakes, a researcher at the University of Southampton (UK). The research adds new details on the benefits of consuming foods rich in Omega-3 to strengthen immunity. Other studies have also shown that using Omega-3 supplements based on fish oil has a beneficial effect on the immune system.

Omega-3 in pregnancy: from mothers to children

Noakes and colleagues’ study involved 123 pregnant women who were randomly assigned to one of two groups. Women in the first group were asked to continue their usual diet, low in fatty fish. The other women were asked to eat 2 servings of salmon per week, corresponding to 3.45 grams total of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the main Omega-3s found in saltwater fish. Researchers collected blood samples from the umbilical cord from the 20th week of pregnancy until delivery to measure Omega-3 and IgE levels (antibodies associated with allergic reactions) and immune response. The children’s health was assessed at 6 months of age. The data showed that adding salmon to the diet was associated with reduced production of certain molecules involved in immune responses triggered by allergens. These molecules included some interleukins (IL). In particular, researchers observed a reduction in IL-2, IL-4, IL-5, and IL-10. Salmon consumption was linked to lower immune system activation by allergens even when one parent suffered from allergies. No differences were found in IgE levels or in the incidence or frequency of eczema between children of women in the two groups.

A matter of doses and interactions

Experts suggest that the lack of effect on IgE protection at 6 months may be due to doses of Omega-3 being too low or that EPA and DHA should be introduced earlier in pregnancy. Indeed, 2 servings of salmon a week correspond to the minimum Omega-3 intake adults need to ensure proper levels of these valuable nutrients. These EPA and DHA doses may not be sufficient to influence the immune system activity in those with a family history of allergies. Furthermore, the researchers noted that in addition to Omega-3, salmon contains other important molecules, such as vitamin D and selenium, which can influence immune system activity. For this reason, the researchers do not exclude that the benefits of including this fish in the diet are linked to the combined action of Omega-3 and these other nutrients.    

Source 

1. Noakes PS, Vlachava M, Kremmyda LS, Diaper ND, Miles EA, Erlewyn-Lajeunesse M, Williams AP, Godfrey KM, Calder PC, “Increased intake of oily fish in pregnancy: effects on neonatal immune responses and on clinical outcomes in infants at 6 mo”, Am J Clin Nutr. 2012 Feb;95(2):395-404. Epub 2012 Jan 4