The Effect of Blueberry Supplementation on Cognitive Functioning in Older Adults

Not Applicable

Withdrawn

• Conditions: Cognitive Decline; Cognition Disorders in Old Age; Aging

• Registration Number: NCT07170943
• Lead Sponsor: Wageningen University

Brief Summary

In this randomized placebo controlled intervention study, the effect of 12 weeks of supplementation with either 150g whole blueberries, freeze-dried blueberry powder (dose equivalent to 150g berries) versus placebo on cognitive functioning will be investigated in older adults.

Detailed Description

Dementia is a public health priority. The prevalence of dementia is rapidly increasing due to population ageing, posing a great social and economic impact on caregivers, families and society. This, in combination with the lack of effective treatment options, demonstrates the urgent need for better understanding on how to prevent and slow down progression of this condition. As ageing and dementia are associated with increased levels of inflammation, nutritional compounds that exhibit anti-inflammatory properties may propose a solution. Blueberries, a good source of anthocyanins, have shown anti-inflammatory properties in several human trials. Therefore, in this randomized placebo controlled intervention study, we aim to investigate the effect of 12 weeks of supplementation with either 150g whole blueberries or freeze-dried blueberry powder (dose equivalent to 150g berries) versus placebo on cognitive functioning in overweight older adults with mild memory complaints. Secondary objectives include the assessment of whole blueberry and freeze-dried blueberry powder supplementation on inflammatory markers, oxidative stress, intestinal health markers, vascular and metabolic health markers, mental well-being, and levels of neurotransmitters.

Study Timeline

• Study First Submitted: 2021-08-26
• Study Start: 2021-11-01
• Primary Completion: 2022-10
• Study Completion: 2022-10-01
• Status Verified: 2025-09
• Study First Submitted QC: 2025-09-05
• Last Update Submitted: 2025-09-05
• Study First Posted: 2025-09-12
• Last Update Posted: 2025-09-12

Recruitment & Eligibility

• Status: WITHDRAWN
• Sex: All
• Target Recruitment: Not specified

Inclusion Criteria

• Age ≥65y
• Overweight, body mass index ≥25 kg/m2
• Mild memory complaints, i.e. ≥22 points on the Cognitive Failure Questionnaire (CFQ) and reporting to have memory complaints and being hampered by these complaints
• No mild cognitive impairment, i.e. ≥26 points on the Montreal Cognitive Assessment (MoCA)
• Able to understand and perform the study procedures

Exclusion Criteria

• Body Mass Index (BMI) ≥35 kg/m2
• Current use of >500 mg/day of acetylsalicylic acid
• Current use of antidepressants
• Current use of medication that affects inflammation (anti-inflammatory medication)
• Current or recent (<1 month) use of berry supplements
• Current or recent (<1 month) use of anti-inflammatory dietary supplements such as fish oil, quercetin, curcumin, resveratrol, and/or other flavonoids
• Current or recent (<3 month) use of antibiotics.
• Berry consumption of more than 1 serving (150g) per week
• Not willing to quit anthocyanin-rich product consumption during the study period
• Allergy to berries/salicylates
• Having a current disease which interferes with the effect of berries/ freeze-dried berry powder and/or with the outcome measure (cognitive functioning), including diagnosis of dementia, psychiatric disorders, gastro-intestinal disease, diabetes, and cancer, as judged by a medical doctor
• Excessive alcohol consumption (on average >21 glasses/week for men and >14 glasses/week for women)
• Current participation in other scientific research

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Verbal fluency	12 weeks	Performance on verbal fluency

Secondary Outcome Measures

Name	Time	Method
Cognitive functioning	12 weeks	Rey Auditory Verbal Learning Test (RAVLT)
Cognitive function	12 weeks	Wechsler Digit Span Task (forward, backward, sequencing) WAIS-IV
Cognition	12 weeks	Stroop Color-Word test
Inflammation - CRP	12 weeks	Inflammatory blood marker: C-reactive protein
Inflammation - TNFalpha	12 weeks	tumor necrosis factor-alpha
Inflammation - IL6	12 weeks	interleukin-6
Oxidative stress	12 weeks	serum superoxide dismutase (SOD)
Intestinal health	12 weeks	Intestinal health markers as measured in blood and feces (microbiota composition, inflammatory fecal markers, microbiota-derived bioactive compounds, intestinal integrity markers
Metabolic health	12 weeks	Blood markers of metabolic health: adiponectin
Mental well-being	12 weeks	profiles of mood states-short form (POMS)
Neurotransmitters	12 weeks	Levels of plasma neurotransmitters (dopamine, serotonin, (nor)adrenaline, and their metabolites)
Vascular health	12 weeks	Markers of vascular health (systolic blood pressure, diastolic blood pressure)