High dietary ratio of omega-6 to omega-3 polyunsaturated acids during pregnancy and prevalence

January 1, 2012 Human Health and Nutrition Data 0 Comments

High dietary ratio of omega-6 to omega-3 polyunsaturated acids during pregnancy and prevalence

Year: 2012
Authors: da Rocha, C.M.M. Kac, G.
Publication Name: Maternal and Child Nutrition
Publication Details: Volume 8; Pages 36 – 48.


Observational studies suggest association between low concentrations of omega 3 family fatty acids and greater risk for post-partum depression (PPD).The objective was to investigate the effect of unbalanced dietary intake of omega 6/omega 3 ratio >9:1 in the prevalence for PPD. The study comprises a prospective cohort with four waves of follow-up during pregnancy and one following delivery. PPD was evaluated according to the Edinburgh Post-partum Depression Scale in 106 puerperae between 2005 and 2007, in Rio de Janeiro, Brazil. Independent variables included socio-demographic, obstetric, pre-pregnancy body mass index (BMI) and dietary intake data, which were obtained by means of a food frequency questionnaire in the first trimester of pregnancy. Statistical analysis involved calculation of PPD prevalence and multivariate Poisson regression with robust variance. PPD prevalence amounted to 26.4% [n 28; confidence interval (CI) 95%: 18.0 to 34.8], and higher prevalence of PPD were observed in women who consumed an omega-6/omega-3 ratio >9:1 (60.0%) and in those with pre-pregnancy BMI<18.5 kg/m2 (66.7%).These variables held as factors associated to PPD in the multivariate model, elevating the chances of occurrence of the outcome in 2.50 (CI 95%: 1.21�5.14) and 4.01 times (CI 95%: 1.96 to 8.20), respectively. Analyses were adjusted for age, schooling, pre-pregnancy BMI, lipids consumption and time elapsed since delivery. It verified an association between omega 6/omega 3 ratio above 9:1, the levels recommended by the Institute of Medicine, and the prevalence of PPD. These results add to the evidence regarding the importance of omega 6 and omega 3 fatty acids in the regulation of mental health mechanisms. (Authors abstract)
Post-partum depression (PPD) is characterized by intense sadness, frequent crying, lack of motivation, lowered interest for eating or for self-care, lack of concentration and a low interest for the newborn. Children of depressed mothers bear greater risks of developing psychopathologies, behavioural and developmental problems, and a delay in cognitive and emotional development. In Brazil, PPD prevalence varies between 13.4% and 37.1% while results from international studies revealed prevalence between 10 and 15%. Recent evidence from observational studies and clinical trials suggest an association between low levels of omega 3 fatty acid, in particular docosahexaenoic acid (DHA). The main objective of this study is to evaluate the association between an unbalanced dietary intake ratio between the omega 6 and the omega 3 fatty acids above 9 in the first trimester of pregnancy and the prevalence of PPD. The prevalence of PPD was 2.5 times greater among Brazilian women whose dietary ratio of omega 6/omega 3 PUFAs in the first trimester of pregnancy was greater than 9/1. These results corroborate the data from an observational study where the increase in DHA concentration in the post-partum, was significantly lower in women with PPD. None of the nutrients evaluated separately showed association with PPD. The evidence of the omega intake effect during pregnancy in PPD prevention are still scanty, although some studies sustain the hypothesis that there is a causal relationship between DHA deficiency and the occurrence of depressive episodes. Fatty acids of the omega 3 family especially alpha linolenic acid (ALA), precursor of the DHA are utilized in the neuronal development of the fetus, a process that poses a high demand of this fatty acid. ALA levels decreased gradually throughout the pregnancy, especially in the last trimester, and remain low until the puerperium because of the release of DHA through the maternal milk. In conclusion, a greater prevalence of PPD was observed in Brazilian women with an unbalance in the dietary intake of the omega 6 and omega 3 ratio in the first trimester of pregnancy, even when this relationship was adjusted for confounding factors. PPD is a serious public health concern, both in developed and in developing countries such as Brazil, and multi-professional preventive approaches are needed. (Editors comments)

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