Binational association between polyunsaturated fatty acid intake and depression in Korea and the US: A cross-national...

Although previous studies suggested higher polyunsaturated fatty acid (PUFA) intake is associated with a reduced risk of depression in single-country samples, binational evidence remains lacking. Thus, we aimed to examine the associations of total PUFA, n-3 PUFA, n-6 PUFA, and subtypes with depression risk in South Korea and the US.

This binational study analyzed data from adults who participated in the Korea National Health and Nutrition Examination Survey (KNHANES; 2014-2020) and in the US National Health and Nutrition Examination Survey (NHANES; 2013-2020). Daily PUFA intake was estimated from 24-h dietary recalls. Depression was defined as a Patient Health Questionnaire-9 score ≥ 10. Each dataset was analyzed independently using weighted quantile sum(WQS) regression and multivariable logistic regression, incorporating subgroup interaction and restricted cubic spline.

Among 17,836 Korean (female; 58.5 %) and 7511 US adults (female; 52.9 %), higher intakes of total PUFA, n-3 PUFA, and n-6 PUFA were associated with lower weighted odds ratios (wORs) for depression in both populations (Korea: wOR, 0.74 [95 % CI, 0.60-0.97]; US: 0.73 [0.55-0.97]). Dose-response showed J-shaped curves, with depression risk lowest at approximately 5-6 % of energy from PUFA in Korea and 7-9 % in the US. WQS model identified docosapentaenoic acid and linoleic acid as key protective components, while subgroup analyses revealed stronger associations among females in Korea and males in the US, as well as non-smokers, never-drinkers, and individuals with lower income.

This binational analysis highlights consistent J-shape associations between PUFA intake and depression risk in both Korea and the US.