Cognitive response to fish oil, blueberry, and combined supplementation in older adults with subjective cognitive impairment

Given evidence that eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and anthocyanin-rich blueberries provide neurocognitive benefit, we investigated long-term supplementation in older adults with cognitive complaints. In a 24-week randomized, double-blind, placebo-controlled trial, elderly men and women received daily fish oil (FO) or blueberry (BB) or both. Diet records confirmed that participants reduced background consumption of EPA, DHA, and anthocyanins as prescribed. Erythrocyte EPA + DHA composition increased in the FO groups (p = 0.0001). Total urinary anthocyanins did not differ between the groups after supplementation but glycoside and native (food) forms increased only in the BB-supplemented groups. The FO (p = 0.03) and BB (p = 0.05) groups reported fewer cognitive symptoms, and the BB group showed improved memory discrimination (p = 0.04), indicating that supplementation improved cognition. Cognitive benefit in the BB group was associated with the presence of urinary anthocyanins reflecting recent BB intake but not with anthocyanin metabolites. However, combined FO + BB treatment was not associated with cognitive enhancement as expected.