More threads by Daniel E.

Daniel E.
by Gary Wenk Ph.D.
November 2, 2022

Recent studies have discovered specific changes in brain function.
  • Daily consumption of the polyphenols found in blueberries may effectively slow cognitive decline.
  • Consuming blueberries improved the speed of processing, which is the time required to complete a mental task.
  • Daily blueberry consumption also significantly protected against cognitive fatigue.

Nearly everyone feels foggy-headed lately. The pandemic, poor sleep, poor diets, political burnout, and a suspicion that you’re slowly becoming cognitively impaired by it all. In addition, we’re all getting older, and our thinking speed is slowing down. We need a safe, non-toxic chemical intervention that has the potential to slow our cognitive decline.

Cognitive slowing is a common characteristic of a long life.​

However, studies have also demonstrated that this decline is not inescapable. Lifestyle changes, including exercise, stopping smoking, and the Mediterranean diet, can produce benefits for cognitive functioning.

Polyphenols found in fruits, vegetables, wine, cocoa, and coffee have been consistently shown to be beneficial to young and old brains. One of the best-known premium sources of polyphenols is blueberries. Research on animals has reported that blueberries can reverse age-related neuronal decline, improve cognition and memory, and increase hippocampal neurogenesis. [For more on the benefits of colorful berries, see my TED Talk.]

Studies on humans have found that eating blueberries is associated with increased blood flow in the brain, but no commensurate improvement was seen in working memory performance. This information about blueberries and brain health is encouraging but needs additional study.

A recent double-blinded study investigated the benefit of eating blueberries on a large group of older people (65-80 yrs, n = 133) for a longer period than any other previous study: six months. The scientists studied brain physiology and used a standardized assessment of cognitive decline, the Cambridge Neurological Test Automated Battery. Subjects were eligible for this study if they had a relatively lousy diet, i.e., consumed fewer than the recommended number of daily servings of fruits and vegetables, and had no signs of cognitive decline, central nervous system disorders, psychiatric illness, diabetes, or gastrointestinal problems that might impair the absorption of nutrients. The subjects consumed either 35 grams of wild blueberry powder or a calorie-matched placebo.

The results of the study showed that consuming blueberries improved the speed of processing. This finding is important because processing speed is a basic component underlying all cognitive abilities. Processing speed indicates the speed that brain regions can move units of chemical or electrical representations of information from one neuron to the next. Processing speed determines the time required to complete a mental task and, as we are all aware, tends to slow down with normal aging. In the current study, daily blueberry consumption also significantly protected against cognitive fatigue. Cognitive fatigue is a decrease in cognitive performance as the demand on our mental faculties increases.

Berries have an array of bioactive moieties, including phenolics, anthocyanins, and ellagitannins, with strong antioxidant potential contributing to their anti-cancer, anti-diabetic, anti-inflammatory, and cardio-protective roles. The results of this study suggest that daily consumption of polyphenols found in blueberries may effectively slow cognitive decline, particularly if the consumption is initiated early in life.

Wenk GL (2019) Your Brain on Food, 3rd Ed, Oxford University Press.

Cheatham CL et al. (2022) Six-month intervention with wild blueberries improved speed of processing in mild cognitive decline: a double-blind, placebo-controlled, randomized clinical trial. Nutritional Neuroscience,
Replying is not possible. This forum is only available as an archive.