Blueberries can add fiber and antioxidants to breakfast, but researchers and nutrition experts say their potential value may reach beyond the morning meal. Evidence has linked the fruit with improvements in certain measures of vascular function and cognition, particularly among older adults.

Walter Willett, an 81 year old Harvard nutrition researcher known for decades of work on diet and chronic disease, told The Washington Post that he eats blueberries almost daily. He typically adds them to oatmeal with Greek yogurt and nuts.

“In study after study, berries appear to be protective against neurodegenerative diseases like Alzheimer's and Parkinson's disease,” Willett told the outlet. He added, “It's an area where we need more research, but berries do seem to stand out, especially blueberries.”

Blueberries are among the most researched fruits, alongside apples, bananas and citrus fruits, according to experts. Studies have examined their possible effects on blood vessels, memory and other aspects of cognitive function.

In a study lasting six months, 115 adults with metabolic syndrome consumed the equivalent of about one cup of blueberries each day. Participants showed improvements in blood vessel function and arterial stiffness, according to Dr. Nadim Geloo, the Virginia based senior medical director of Abbott's structural heart division.

Those findings do not mean blueberries directly prevent heart attacks or strokes. Researchers have often focused on markers such as vascular function rather than documenting whether participants later experienced major cardiovascular events.

“Most [studies] small and short, often use freeze-dried powder rather than whole fruit, measure markers like blood vessel function rather than actual heart attacks or strokes and are frequently funded by the blueberry industry,” Geloo told Fox News Digital.

Research has also found improvements in memory and other cognitive measures, especially among older adults. Dr. Michael Aziz, an internist and physician at Lenox Hill Hospital in New York City, said the observed effects were modest.

Aziz also noted that research has not demonstrated that blueberries can prevent Alzheimer's disease. That distinction leaves blueberries as a potentially beneficial part of a diet, rather than a proven safeguard against cognitive disease.

California based biomedical researcher Rhonda Patrick discussed the evidence surrounding blueberries on her FoundMyFitness podcast. “The strongest benefit is vascular,” she said.

Patrick described blueberries as one of the more strongly supported foods containing abundant polyphenols, plant compounds studied for their potential health effects and antioxidant properties. She said about one cup per day represents a practical amount.

Studies involving older adults have also found improvements in some measures of memory and cognitive flexibility, Patrick noted. Observational research over longer periods has linked berry consumption with slower cognitive decline, although those studies cannot establish that blueberries caused the difference.

A Japanese research team also studied pterostilbene, a natural polyphenol found in berries and grapes. In cultured mouse skeletal tissue, the compound increased fatty acid oxidation and reduced lipid accumulation.

Despite the limits of the available evidence, experts said blueberries remain a worthwhile food choice. “While there is no 'magic bullet,' there's nothing to lose by including more berries in your diet,” New York based registered dietitian nutritionist Elisa Bremner told Fox News Digital.

Bremner said she also eats blueberries nearly every day. “I have heard blueberries called 'brainberries,' due to all the research on cognitive function associated with them,” she said.

One cup of blueberries provides about 3.6 grams of fiber, according to Bremner. Fiber helps slow digestion, while combining blueberries with foods rich in protein, such as yogurt, may further slow the release of sugar.

Both fresh and frozen blueberries are practical options. Bremner said frozen fruit can provide a convenient and less expensive way to eat fruit throughout the year.

The evidence does not show that everyone must consume exactly one cup daily, nor does it establish that blueberries prevent disease. Bremner therefore recommends a varied and balanced diet instead of depending on one fruit for health benefits.

Willett described a similarly broad dietary approach to The Washington Post. His overall eating pattern emphasizes whole grains, fruits, vegetables, proteins from plants, healthy fats and modest amounts of meat and dairy.