The new study, published in Nutrition, shows that supplementation with olive polyphenols increase levels of the proteins (known as neurotrophins) nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) – both of which play key roles in the development, growth, and survival of brain cells.
Led by Dr Marco Fiore from the Institute of Cell Biology and Neurobiology, Italy, the research team supplemented mice with an olive extract (Phenolea Active Complex, Phenofarm) for ten days before testing whether the polyphenols had an effect on NGF and BDNF content and the expression of their receptors, TrkA and TrkB, respectively, in the mouse brain.
“Polyphenols extracted from olive may increase the levels of NGF and BDNF in the crucial tissues of the mouse limbic system and in the olfactory bulbs, brain areas playing a key role in learning and memory processes, and in the regulation of the proliferation and migration of endogenous neuronal stem cells present in the mammalian brain,” said the research team.
“To our knowledge, this is the first study to demonstrate in a mouse model that a mixture of polyphenols extracted from olive pomace, obtained in the process of extra virgin olive oil production, may have effects on NGF/BDNF levels in selected brain areas,” they added.
Fiore and his colleagues noted that various studies have suggested that dietary polyphenols can help to protect against cancer and cardiometabolic and neurodegenerative diseases, however very few have investigated their effect on the development or protection of cognitive functions.
“Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are neurotrophins that play key roles in brain cell development, growth, and survival,” they said.
The team supplemented mice with either 10 mg/kg of polyphenols extracted from olive residues (six mice) or a control diet (six mice) for ten days, before measuring the effects of the intervention on biomarkers in the blood and certain brain regions.
“We found NGF and BDNF elevation in the hippocampus and olfactory bulbs and a decrease in the frontal cortex and striatum,” revealed the authors – who added that the findings were associated with increased expression of TrkA and TrkB receptors in the hippocampus and olfactory bulbs but not in the striatum and frontal cortex.
“Altogether, this study shows that olive polyphenols in the mouse may increase the levels of NGF and BDNF in crucial areas of the limbic system and olfactory bulbs, which play a key role in learning and memory processes,” concluded Fiore and his team.
Volume 29, Issue 4, Pages 681–687, doi: 10.1016/j.nut.2012.11.007
“Effects of olive polyphenols administration on nerve growth factor and brain-derived neurotrophic factor in the mouse brain”
Authors: Sara De Nicoló, Luigi Tarani, Mauro Ceccanti, Mariateresa Maldini, et al