Cranberries linked to reduction in 'bad' cholesterol levels say UK researchers
The 12-week study looked into the impact of cranberry consumption on cognition, brain function and neuronal signalling in an aging population.
Results revealed distinct improvements in recall of everyday events (visual episodic memory) and neural functioning among participants in the test group, compared to the placebo. Scientists also observed a significant decrease in low-density lipoprotein (LDL) cholesterol.
Lead researcher Dr David Vauzour commented: “This supports the idea that cranberries can improve vascular health and may in part contribute to the improvement in brain perfusion and cognition.
"Demonstrating in humans that cranberry supplementation can improve cognitive performance and identifying some of the mechanisms responsible is an important step for this research field.”
Degenerative cognition
Degenerative neurological conditions (such as dementia) are the predominant risk factor in older adults. As the aging population grows, maintaining quality-of-life in later years has become a global challenge, the authors write.
Dementia incidence is projected to double every 20 years and affect an estimated 152 million people by 2050. Such startling figures increase the urgency for effective solutions to limit and manage disease progression.
Dr Vauzour explained: “There is no known cure, so it is crucial that we seek modifiable lifestyle interventions, such as diet that could help lessen disease risk and burden.”
Cranberries (Vaccinium macrocarpon) are rich in polyphenols such as anthocyanins, proanthocyanidins, flavonols and hydroxycinnamic acids, and are recognised for their antioxidant and anti-inflammatory effects, he explains: “Foods rich in anthocyanins and proanthocyanidins have been found to improve cognition.”
Past studies have shown that higher dietary flavonoid intake is associated with slower rates of cognitive decline and dementia, but there is little evidence on the impact of cranberries on cognition and brain health in humans.
"We wanted to find out more about how cranberries could help reduce age-related neurodegeneration," said Dr Vauzour.
The current study investigated the long-term impact of freeze-dried cranberry powder on cognitive health in healthy adults.
Study protocol
Male and female participants were recruited through an online database (Join Dementia Research) and from an existing database at the University’s Norwich Medical School.
Subjects were screened for eligibility and were excluded if they presented with any form of dementia or significant memory complaint. Researchers were particularly keen to recruit married couples to reduce the variability in dietary patterns.
At a pre-intervention baseline visit, participants were given a standardised breakfast and submitted to global cognitive screening, followed by a 30-min MRI scan. They were randomly assigned a sachet of the study powder (4.5g each) or placebo at the end of the visit and instructed to take two sachets per day (morning and night).
The powder dose was equivalent to one cup or 100g of fresh cranberries and provided 281mg or proanthocyanidins, with 20mg flavonols and 59mg anthocyanins.
The placebo powder matched the active cranberry powder for taste, colour, fructose, total sugar, and calories and comprised a blend of water, maltodextrin, citric acid, Lorann oils, fructose, and grape shade.
Participants were instructed to maintain their normal diet and avoid non-essential supplementation that could have an impact on study findings.
Follow-up assessment at 12 weeks repeated the baseline tests and also required subjects to provide fasted blood and urine samples.
Findings
Results showed that sustained intake of cranberry powder had a significant positive effect on specific aspects of cognitive function and effectively reduced atherosclerotic cholesterol profiles, including LDL cholesterol and total cholesterol levels.
Cranberry intake appeared to benefit male participants more than females, where a steep decrease in body weight and associated parameters (such as fasting glucose, high-density lipoprotein (HDL) cholesterol, blood pressure) were more controlled.
There was no change in working memory and executive function and no reported differences in structural grey matter between the two study groups.
Researchers noted that cranberry intake was particularly beneficial for male participants.
Dr Vauzour concludes: "The findings of this study are very encouraging, especially considering that a relatively short 12-week cranberry intervention was able to produce significant improvements in memory and neural function.
"This establishes an important foundation for future research in the area of cranberries and neurological health."
Source: Frontiers in Nutrition
Published online: doi: 10.3389/fnut.2022.849902
‘Chronic Consumption of Cranberries (Vaccinium macrocarpon) for 12 Weeks Improves Episodic Memory and Regional Brain Perfusion in Healthy Older Adults: A Randomised, Placebo-Controlled, Parallel-Groups Feasibility Study’
Authors: Emma Flanagan
