Types of fish consumption differ across socioeconomic strata and impact differently on plasma fish-based omega-3 fatty acids: A cross-sectional study

Purpose: We investigated the associations of socioeconomic position (SEP) with total and type of fish intake in a large general population and validated whether types of fish intake were differently associated with plasma EPA and DHA in a subset of the population.
Methods: From the Lifelines cohort study, 94 246 participants aged 44 ± 13 years old were included to test the association of two SEP indicators, i.e., education level and household income level, with dietary intakes of total, fatty, lean, fried, and other types of fish. In a subset of 575 participants (mean age: 50 ± 13 years), EPA and DHA levels were measured in plasma phospholipids and triglycerides. Dietary fish intake was assessed using Food Frequency Questionnaire. Linear regressions were applied and adjusted for relevant covariates.
Results: Compared to the high education level, lower education levels were negatively associated with total, fatty, lean, and other fish intake (p<0.001 for all), and positively associated with fried fish intake (β (SE): 0.04 (0.04), p<0.001 for middle education; 0.07 (0.04), p<0.001 for low education), independently of relevant covariates. Similar results were observed for income levels. In the subset population, total and fatty fish intakes were positively associated with plasma EPA and DHA (p<0.02 for all). Lean and other fish intakes were positively associated with only DHA (p<0.008 for all), but not EPA, while fried fish was not associated with either EPA or DHA in plasma (p>0.1 for all).
Conclusion: Lower SEP was associated with a lower total intake of fish, and of fatty and lean fish, but with higher intake of fried fish. Fried fish was not associated with the fish-based EPA and DHA in plasma. Hence, SEP-related differences in fish consumption are both quantitative and qualitative.

Keywords: fishes; omega-3 fatty acids; ultra-processed food; socioeconomic status; food intake