|BIELINSKI, DONNA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|LAU, FRANCIS - Shaklee Corporation|
|WILLIS, LAUREN - Georgia Health Sciences University|
|CAREY, AMANDA - Simmons College|
|JOSEPH, JAMES - Former ARS Employee|
Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2015
Publication Date: 9/21/2015
Citation: Shukitt Hale, B., Bielinski, D., Lau, F., Willis, L.M., Carey, A., Joseph, J. 2015. The beneficial effects of berries on cognition, motor behavior, and neuronal function in aging. British Journal of Nutrition. 114:1542–1549. doi:10.1017/S0007114515003451.
Interpretive Summary: Previous research has shown that after feeding old rats with diets supplemented with strawberry or blueberry, age-related deficits in brain function were reversed. These effects may be the result of benefits of the chemical compounds found in the berries, which may decrease indications of cellular stress, increase the formation of new brain cells, and increase processes involved in learning and memory. To examine these mechanisms, aged rats were given either normal rat chow or that supplemented with 2% strawberry or 2% blueberry for 8 weeks, followed by analysis of rats’ performance on behavioral tests and by molecular measurements of brain cell function. The results showed that rats consuming the berry-supplemented diets exhibited enhanced performance on tests focused on muscular movement (strength, coordination, and balance), and also showed improvement on tests focused on mental processes, specifically the short-term memory required in navigational learning. Additionally, the rats supplemented with blueberry and strawberry diets showed increased growth of new brain cells and increased levels of a molecular growth factor in the brain, although the improvements in memory performance could not solely be explained by these increases. The various chemical compounds in these berry fruits may have additional mechanisms of action that could account for their relative differences in efficacy.
Technical Abstract: Previously, it has been shown that strawberry or blueberry supplementations, when fed to rats from 19-21 months of age, reverse age-related decrements in motor and cognitive performance. We have postulated that these effects may be the result of a number of positive benefits of the berry polyphenols including decreased stress signaling, increased neurogenesis, and increased signals involved in learning and memory. Thus, the present study was carried out to examine these mechanisms in aged animals given a control, 2%, strawberry, or 2% blueberry supplemented diet in aged Fischer 344 rats for 8 weeks for their effectiveness in reversing age-related deficits in behavioral and neuronal function. The results showed that rats consuming the berry diets exhibited enhanced motor performance and improved cognition, specifically working memory. Additionally, the rats supplemented with blueberry and strawberry diets showed increased hippocampal neurogenesis and expression of insulin-like growth factor 1 (IGF-1), although the improvements in working memory performance could not solely be explained by these increases. The diverse polyphenolics in these berry fruits may have additional mechanisms of action that could account for their relative differences in efficacy.