NATION — Flavonoid-rich foods, such as berries, and beverages, such as green tea, could help lower a person’s risk of dementia. Flavonoids are potent antioxidants found in plant-based foods, providing various health benefits.
A recent study suggests that consuming higher levels of flavonoid-rich foods could notably decrease the risk of dementia, especially for individuals at a higher risk. Berries, tea, and red wine were observed to provide the most benefits, but it’s advisable to prioritize berries and tea over alcohol for brain health.
The Growing Concern of Dementia
With the world’s population getting older, the number of individuals affected by dementia is projected to rise from 50 million to 152 million by 2050. There is currently no cure for dementia, so prevention is essential.
Understanding Flavonoids
Flavonoids are bioactive compounds found in plant-based foods like fruits and vegetables. They offer numerous health benefits, including reducing inflammation, improving blood vessel function, and potentially forming new neurons in the brain.
New Study Highlights Flavonoid Benefits
A new observational study involving nearly 122,000 adults suggests that a flavonoid-rich diet may significantly lower the risk of dementia, especially for those with genetic predispositions or risk factors like high blood pressure or depression.
This study supports existing research on the role of flavonoids in helping to slow cognitive decline, indicating that incorporating more flavonoid-rich foods into the diet could be a strategic approach to reducing dementia risk. The findings are published in JAMA Network.
How Flavonoid Intake Affects Dementia Risk
Study Details
This study, led by researchers at Queen’s University Belfast in Northern Ireland, United Kingdom, examined the relationship between diet and dementia using data from adults aged 40 to 70 from the UK Biobank.
The study included participants with valid data, defined as having at least two 24-hour dietary assessments with realistic energy intakes, along with other necessary information. Those who had an existing diagnosis of dementia or who had withdrawn their consent were not included in the study.
The final sample of 121,986 adults included 55.6% females, with an average age of 56.
Flavonoid-Rich Foods Examined
Researchers evaluated participants’ adherence to a “flavodiet score” and intake of certain flavonoids by adding up the servings per day of key flavonoid-rich foods, such as:
- tea (black and green)
- berries (like strawberries and blueberries)
- red wine
- apples
- grapes
- oranges
- grapefruit
- sweet peppers
- onions
- dark chocolate
The main focus was the occurrence of all-cause dementia, which researchers determined using hospital and death records.
In additional analyses, the researchers also considered genetic risk, high blood pressure, and depression symptoms.
Participants were considered to be at high genetic risk for dementia if they had the apolipoprotein E (APOE) ε4 genotype or had among the highest Alzheimer’s disease-related polygenic risk scores (PRS).
Study Findings: High Flavonoid Intake Linked to Reduced Risk of Dementia
Over a mean follow-up of 9.2 years, there were 882 reported cases of dementia. People who ate the most flavonoid-rich foods were more physically active, had a lower body mass index, and experienced less financial hardship than those who ate the least.
Researchers observed that participants with the highest flavonoid intake, consuming an additional 6 daily servings of flavonoid-rich foods on average, were 28% less likely to develop dementia than those with the lowest intake.
Upon further analyses, this association was especially noticeable in individuals with high genetic risk, hypertension, or depressive symptoms, showing risk reductions of 43%, 30%, and 48%, respectively.
Regarding specific foods, consuming at least two of the following daily: five servings of tea, one serving of red wine, or half a serving of berries provided the greatest protective benefit, reducing dementia risk by 38% compared to those who did not consume these amounts.
In fact, if tea, red wine, and berries were excluded from flavodiet scores, the protective effect diminished, suggesting that these may be the primary contributors to the reduced risk of dementia.
Higher intakes of specific flavonoid subclasses—anthocyanins, flavan-3-ols, flavonols, and flavones—were also linked to a lower dementia risk.
Study Limitations
Eliza Whitaker, MS, RDN, a registered dietitian and medical nutrition advisor at Dietitian Insights, who was not involved in the study, noted that while the study had a large sample size, “providing a good representation of the population studied,” the research still had some notable limitations.
Along with the use of self-reported dietary data, which can introduce bias, the UK Biobank participants are a healthier population, with a small number of non-flavonoid consumers, “making it challenging to generalize results to other populations,” she said.
Additionally, reverse causation might have occurred, where participants who developed dementia changed their dietary preferences before the onset of symptoms.
Should We Add Tea, Berries, Red Wine to Our Diet to Lower Dementia Risk?
Thomas M. Holland, MD, MS, a physician-scientist and assistant professor at the RUSH Institute for Healthy Aging, RUSH University, College of Health Sciences, who was not involved in the study, was asked about the findings. He said that “from a real-life perspective, the results are encouraging,” especially for those at high genetic risk for dementia or with modifiable risk factors such as high blood pressure and depression.
However, he pointed out that while tea and berries have been consistently shown to support brain health, red wine’s impact remains controversial. He also highlighted the World Health Organization’s (WHO) advice against alcohol consumption, due to its health risks, including cancer.
Holland said this raises concerns about alcohol’s role in dementia prevention, highlighting challenges in observational studies, such as how alcohol intake is categorized and the potential for biases.
“The study does not fully disentangle the effects of alcohol from those of flavonoids found in wine,” he emphasized.
However, Holland suggests that flavonoids in wine, like tannins and anthocyanins, are more likely responsible for any observed benefits than the alcohol itself.
He noted that “as the study itself acknowledges, further research is needed to clarify the relationship between moderate alcohol consumption and dementia risk.” He ultimately advised focusing on incorporating tea, berries, and other nutrient-dense plant foods for dementia prevention:
“The study highlights the positive effects of tea, berries, and wine, but as we move away from recommending alcohol, it’s essential to clarify that we wouldn’t encourage non-drinkers to start consuming wine. Tea, a product of leaves, may be nutritious, but consuming whole, leafy greens could offer even greater benefits. Berries — such as strawberries, blueberries, and raspberries—are rich in antioxidants and flavonoids, and dark leafy greens like kale, spinach, and arugula are also excellent sources of flavonols.”
In addition to incorporating more flavonoid-rich foods to reduce dementia risk, among other healthy lifestyle changes, both Holland and Whitaker recommend adopting a dietary pattern like the MIND diet.
This diet, a hybrid of the Mediterranean diet and Dietary Approaches to Stop Hypertension (DASH), has been shown to benefit brain aging and may further reduce the risk of developing dementia.
Study Funding and Disclosures
During the course of the study, one author disclosed receiving grants and personal fees from the United States Highbush Blueberry Council (USHBC), an agricultural commodity board with oversight from the United States Department of Agriculture (USDA).
MNT contacted USHBC for comment regarding this reported conflict of interest.
In response, Leslie Wada, PhD, RD, Senior Director of Nutrition and Health Research at USHBC, told MNT that “for studies that the USHBC supports, it has no involvement in the collection, analyses, or interpretation of data, and places no restriction on the publication of the data.”
However, she clarified that the “USHBC did not fund this study.”
The research was funded by the Co-Centre for Sustainable Food Systems and a PhD studentship from the Department for the Economy, Northern Ireland.
— Kelsey Costa, MS, RDN
