Blueberries may help reduce dementia risk in vulnerable populations

Regularly consuming blueberries may protect against cognitive decline in people who are at risk of dementia, according to a new study (Nutrients. 2022;14[8]:1619).

More than 55 million people around the world are living with dementia, according to Alzheimer’s Disease International. Every 20 years, that figure doubles, putting the number of people living with dementia at close to 140 million in 2050.

There is no treatment for dementia—a disease that costs more than $1.3 trillion worldwide—but researchers have uncovered mind-boosting benefits derived from certain foods and beverages, such as coffee, tea, vitamin B-rich fruits and vegetables—and now, blueberries.

Blueberries are packed with micronutrients and bioactive flavonoid compounds such as anthocyanins. Anthocyanins lend the potent berry its deep blue and purple coloring and also protect the plant from stressors such as infection and oxidation.

Researchers suspect these protective effects are translated to humans, as well.

The present study, published in Nutrients, builds on preliminary studies touting the potential of blueberries to improve cognitive performance and brain function. The study focused on middle-age populations with the goal of identifying methods of disease prevention and risk reduction.

For the present study, researchers administered the equivalent of one-half cup blueberries as whole, freeze-dried blueberry powder, or placebo, to participants—overweight men and women ages 50 to 65 with subjective cognitive decline. This form of cognitive impairment is considered one of the earliest symptoms of Alzheimer’s disease and dementia.

The participants were also insulin-resistant and were considered to have an elevated risk for future dementia.

Participants were asked to abstain from berry fruit consumption during the 12-week trial, with exception of the blueberry powder, which was consumed once daily. Researchers performed various pre- and post-intervention assessments to measure cognitive abilities such as executive functions, which include working memory, self-control and mental flexibility, which is the ability to adapt as circumstances change.

Results showed daily consumption of blueberry powder improved performance on a lexical access task and reduced interference of extraneous information in memory, which, according to researchers, reflects improved executive control among the blueberry-consuming participants. The blueberry group also reported reduced memory encoding difficulty in daily life activities as measured by the Everyday Memory Questionnaire—a subjective measure of memory failure in everyday life.

“The findings are a demonstration that blueberry supplementation can produce measurable cognitive benefit in the context of aging and insulin resistance,” researchers wrote.

Further, blueberry supplementation produced a reduction of fasting insulin and a trend for increased mitochondrial uncoupling. Mitochondrial uncoupling has been associated with greater longevity and reduced oxidative stress.

“In particular, mild or partial uncoupling has been associated with the actions of certain anthocyanins and with reduced oxidative stress, preservation of tissue function with aging, and with extended life span,” researchers wrote.

The study’s findings, researchers wrote, position blueberries as a potentially powerful tool to protect against neurocognitive decline in vulnerable individuals.

Rachel Adams joined Informa’s Health & Nutrition Network in 2013. Her career in the natural products industry started with a food and beverage focus before transitioning into her role as managing editor of Natural Products INSIDER, where she covered the dietary supplement industry. Adams left Informa Markets in 2019.