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

Abstract

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.

Role of phytochemicals as nutraceuticals for cognitive functions affected in ageing

“…Small RCTs ( n = 26–37) with blueberry nutraceuticals have shown oral intake of a concentrate containing either 387 mg of anthocyanidins or 12 g of lyophilised blueberries for 12 weeks improves cognitive abilities in healthy older adults (Bowtell, Aboo‐Bakkar, Conway, Adlam, & Fulford, ; Miller, Hamilton, Joseph, & Shukitt‐Hale, ). Larger RCTs ( n = 94–122) also conclude that blueberry extracts improve memory performance in older adults when taken for periods of 3 to 6 months (McNamara et al, ; Whyte, Cheng, Fromentin, & Williams, ). Other RCTs have concluded that flavonoid‐rich citrus juices improve cognitive functions in healthy older adults ( n = 37) after 8 weeks of intake (Kean et al, ) and in healthy middle‐aged adults ( n = 22) after acute administration (Alharbi et al, ).…”

Berry Supplementation and Their Beneficial Effects on Some Central Nervous System Disorders

“…Similarly, it has been observed that blueberry powder (Vaccinium sp.) supplementation in patients with Alzheimer's disease and cognitive decline reduces the self-reported inefficiencies in daily functioning [90] (Table 3).…”

DHA Manuscript

“…The details of the studies are provided in Table 2 Table 2. Few authors investigated the beneficial effects of variable doses / combinations of DHA and reported as larger study [24][25][26][27]. Data from each of these sub studies (doses / combinations of DHA) were extracted and used as separate studies.…”

“…Overall studies report over 80% adherence to the intervention. Due to unavailability of dispersion data (such as SD / CI) for various cognitive assessments, McNamara et al (2018) was not part of the Meta-analysis (quantitative results) however was considered as part of the review (qualitative results) [26].…”

“…We explored, if higher doses of DHA supplementation altered the results by performing subgroup of studies, those supplemented ≥ 750 DHA / day [30,31,[24][25][26]. The results of subgroup analysis were similar to the primary results indicating no significant improvement with DHA supplementation.…”