The researchers of a recent study published in Nutrients examined whether consuming wild blueberry extracts (WBE) may improve cognitive performance in an acute period, including recognized times of impaired functioning.
Study: Wild Blueberry Extract Intervention in Healthy Older Adults: A Multi-Study, Randomised, Controlled Investigation of Acute Cognitive and Cardiovascular Effects. Image Credit: Kolpakova Svetlana/Shutterstock.com
Background
Flavonoid-rich foods like berries can enhance cognitive function and happiness across the lifespan, especially in healthy and cognitively impaired individuals.
Studies have shown that blueberry therapy can improve vascular function and slow cognitive decay in older individuals.
However, additional studies are needed to establish whether additional stabilizing agents can produce high bioactivity and advantages with a modest product dosage and whether blueberry intake can improve cognitive and cardiovascular health among healthy older adult individuals.
About the study
In the present randomized, double-blinded, placebo-controlled cross-over trial, researchers examined the effectiveness of wild blueberry extracts in sustaining episodic memory and executive function and cardiovascular consequences among healthy older individuals (ROAB trial).
They aimed to duplicate cognitive decline reduction during an expected post-prandial drop while also enhancing cardiovascular outcomes after acute supplementation with 222mg of wild blueberry extract (BEAT trial).
In the ROAB trial, 28 subjects received WBE doses of 111.0 mg, 222.0 mg, 444.0 mg, and 888.0 mg, or a placebo (inert artificially colored maltodextrin 300 mg, once daily, 3-hard capsule regimen) during five weeks, followed by a one-week washout.
The researchers evaluated outcomes at baseline, two hours, four hours, and six hours following the intervention, with the intervention happening immediately after study initiation.
In the BEAT experiment, the team administered 222 mg of wild blueberry extracts or a placebo (one-week washout) to 45 subjects and evaluated outcomes at baseline and six hours, corresponding to a post-prandial drop in cognitive function, with the intervention occurring immediately after baseline.
The 222 mg WBE intervention coincided with known maxima in serum blueberry polyphenols two hours after dosage, corresponding to an expected reduction in post-prandial performance.
Study participants were healthy older individuals recruited via the University of Reading Psychology Department's Older Adult Panel, the University of the Third Age, local community noticeboards, and other activity organizations in Reading, United Kingdom, and the surrounding region.
Study participants were aged 68 to 75 years without a prior history of diabetes, metabolic diseases, substance addiction, or neurological or mental illnesses.
The study excluded smokers, vegetarians, individuals with a body mass index (BMI) ≥30, those allergic to WBE, and those who consume more than two alcoholic beverages each day.
They also excluded individuals who used alternative drugs to boost cognitive function and memory the month before the study began and those who had participated in other studies in the preceding 30 days or cognitive trials in the previous six months.
The researchers used Folin-Ciocalteu tests to determine total phenolic content and liquid chromatography to quantify anthocyanins.
They used the Mini-Mental State Examination (MMSE), the National Adult Reading Test (NART), the Frequency of Forgetting (FoF) scale, Ravens Progressive Matrices (RPM), Rey's Auditory Verbal Learning task (RAVLT), the Corsi Blocks task, the Task Switch task (TST), and the Trail Making tasks A and B (TMT-A and B) to assess cognitive function.
Mood was measured using the Positive and Negative Affect Scale (PANAS). They produced composite scores consistent with the Alzheimer's Disease Composite Score (ADCOMS) and the Z-scores of Attention, Verbal Fluency, and Episodic Memory for Nondemented Older Adults Composite (ZAVEN) scores. They used linear mixed modeling (LMM) for analysis.
Results and discussion
The study showed that wild blueberry extract, specifically 222 mg, caused a significant decrease in executive function at the 4-hour timepoint compared to placebo.
However, 222 mg of wild blueberry extract significantly decreased diastolic and systolic blood pressures compared to a placebo. WBE 222 mg had a quicker EF reaction time during the projected post-lunch decrease.
The ROAB experiment discovered that WBE 111 mg therapy resulted in lower executive performance after 4 hours compared to the placebo. WBE 888 mg produced quicker response speeds, although sessions were a strong predictor of CRT accuracy.
WBE 222 mg was associated with reduced systolic and diastolic blood pressures compared to placebo, with the highest values occurring during the six hours.
Flavonoids may have comparable biological processes in acute and chronic states, such as boosting cerebral blood flow (CBF) via better endothelial function and nitric oxide generation.
Flavanoids enhance nitric oxide (NO)-mediated vasodilation, which improves cerebral blood flow and cognitive performance by enhancing metabolic substrate supply. Flavonoid eating may also help to lower blood pressure.
Based on the study findings, wild blueberry extracts may have cardiovascular benefits and minimize cognitive decline in healthy older individuals when paired with a post-prandial dip.
Acute WBE supplementation enhanced response speeds while decreasing cognitive performance on executive function tests. Post-lunch testing may improve the circadian decrease in cognition ability.
Low dosages of WBE (222 mg, 444 mg, and 111 mg) enhanced episodic memory and executive function. Further study is required to determine the efficacy of wild blueberry extracts in those with minor cognitive deficits and to align cognitive test schedules.
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