Foods rich in certain (poly)phenols, particularly flavonoids, such as berries and cocoa, have been shown to improve measures of vascular function as well as cognitive performance in human intervention studies. This is a randomized, double-blind, placebo controlled, parallel trial investigating the effects of daily blueberry (poly)phenol consumption on vascular function and cognitive performance in healthy elderly individuals. The study will be conducted at King's College London, Franklin-Wilkins Building.

Eligible subjects will be healthy males and females aged 65-80.

To date no study has investigated whether daily blueberry consumption can induce an increase in cerebral blood flow, with subsequent improvements in vascular and cognitive function. In this study, the investigators aim to directly link daily blueberry consumption with improved vascular function, increased cerebral blood flow and positive cognitive outcomes in healthy elderly individuals. The investigators will use a large group of elderly individuals' representative of a healthy population, both males and females, aged 65-80 years to evaluate the health effects of daily blueberry consumption.

The main aim is to investigate whether improvements in vascular and cognitive function previously seen after blueberry consumption can be seen following 3-months daily consumption in elderly individuals, and whether enhanced cognitive performance is correlated with increased cerebral blood flow. The investigators hypothesise that daily consumption of an anthocyanin rich blueberry drink will improve cognitive performance and vascular function, increasing cerebral blood flow, in healthy older individuals.

Inclusion Criteria:

• Participants will include 60 healthy male and female volunteers, aged 65-80.
• Volunteers will be able to understand the nature of the study and able to give signed written informed consent.
• Subjects willing to maintain their normal eating/drinking habits and exercise habits to avoid changes in body weight over the duration of the study.

Exclusion Criteria:

• Manifest cardiovascular diseases including coronary artery disease, cerebrovascular disease and peripheral artery disease.
• Hypertensive, as defined as SBP superior or equal to 140 mmHg or DBP superior or equal to 90 mmHg.
• Obese participants, defined as BMI superior or equal to 30.
• Diabetes mellitus and metabolic syndrome.
• Acute inflammation, terminal renal failure or malignancies.
• Allergies to berries or another significant food allergy.
• Subjects under medication or on vitamin/dietary supplements (within 2 weeks of baseline).
• Subjects who have lost more than 10% of their weight in the past 6 months or are currently on a diet.
• Subjects who reported participant in another study within one month before the study starts.
• Subjects who smoke cigarettes irregularly.
• MCI or dyslexic or unable to complete the cognitive function tasks for any reason such as visual impairments.
• Subjects who require chronic antimicrobial or antiviral treatment.
• Subjects with unstable psychological condition.
• Subjects with history of cancer, myocardial infarction, cerebrovascular incident.
• Any reason or condition that in the judgment of the clinical investigator(s) may put the subject at unacceptable risk or that may preclude the subject from understanding or complying with the study's requirements.