Associations between dietary factors and fatty acid status during early pregnancy among women in Johannesburg, South Africa: the NuPED study

Background: Fatty acids (FAs) play a key role in fetal development and pregnancy outcomes.  Objective: To  assess FA intake, status, and associations between dietary factors and FA status patterns during early pregnancy among women living in Johannesburg, South Africa.  Methods: For this cross-sectional study, we measured red blood cell (RBC) FA composition using GC-MS and assessed FA intake using a validated quantitative food frequency questionnaire in 250 pregnant women at <18 weeks’ gestation. Nutrient patterns and RBC FA composition patterns were identified using principal component analysis.  Results: Dietary monounsaturated FA (MUFA) and total n-3 FA intakes (mg/day) were below the acceptable macronutrient distribution range. The median n-6:n-3 FA intake ratio was 38.5:1, and the n-3 index was 5.3%. Three nutrient patterns and four FA status patterns emerged. A nutrient pattern high in plant protein and fibre but low in fat positively associated with a FA pattern high in long-chain SFA (β=0.03, p=0.026) and negatively with a FA pattern high in short-chain SFA and trans fats, but low in DHA and n-6 FAs (β=-0.03, p=0.011). A nutrient pattern high in fatty and processed foods negatively associated with FA patterns high in long-chain SFA (β=-0.05, p=0.038) and high in ALA, EPA and n-3 DPA (β=-0.06, p=0.017). Fish/seafood intake correlated positively with the FA pattern high in n-3 PUFA (r=0.181, p<0.01), while cakes, biscuits, puddings (r=-0.148, p<0.05) and red meat (r=-0.137, p<0.05) correlated negatively.   Conclusion: In this study, pregnant women exhibited low n-3 intake and n-3 index status. The direction of the observed associations between nutrient intake and RBC fatty acid (FA) status patterns may aid in the interpretation of nutrient intake and FA status, which results from both dietary intake and metabolic processes.