In a study published last month in the Annals of Neurology, researchers reported that consumption of berries and flavonoids showed a slower rate of cognitive decline in women aged 70 and older.* Using data from the long-running Nurses’ Health Study of 122,000 registered nurses, the researchers conducted assessments on 16,010 women.
The Nurses Health Study began in 1976. Every four years they were questioned on their eating habits. Between 1995 and 2001, more than 16,000 women aged 70 and older underwent memory testing. The researchers at Brigham Women’s Hospital/Harvard Medical School in Boston and the German Center for Neurodegenerative Diseases in Bonn, Germany found that greater ingestion of blueberries and strawberries correlated with slower rates of cognitive decline for up to 2.5 years. The women who showed the most improvement consumed two or more servings of the berries each week.
Berries contain a particularly high number of flavonoids called anthocyanidins that can cross the blood brain barrier and localizing themselves in the hippocampus, an area of the brain known for memory and learning. Investigational drugs and other alternative therapies often fail because they cannot cross the blood brain barrier or reach the hippocampus.
Flavonoids are known to have antioxidant and anti-inflammatory characteristics which can benefit the brain. The study’s authors acknowledge that previous small trials of berry supplementation have shown positive results as well. In some earlier non-related studies inflammation and stress have been shown to contribute to a reduction in brain functioning. Increasing flavonoid consumption might slow these harmful effects, but more study is needed to test this hypothesis.
The authors acknowledge that this was an observational study that relied on accurate dietary reporting from the nurses. In addition they do not know if the results would apply equally to men since all of the people they studied were female. For the future the authors recommend that men be part of the cohort. Finally, they encourage older adults to consume berries as they offer an easy dietary modification that may delay memory decline and will not cause harm.
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