Nutrition for the ageing brain: towards evidence for an optimal diet

As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline

Effects of blueberry supplementation in BDNF mRNA levels in the hippocampus and cortex.

<p><b>A) Dentate Gyrus (DG) (white bars) and Polymorphic Cell Layer (PCL) (grey bars) of the hippocampus, B) Cortex, C) CA1 D) CA3.</b> Representative pictures of hippocampal and cortical sections showing BDNF mRNA expression from 1 animal from the control (C) group, one from the BB group (BB), one from the Anthocyanins group (A) and one from the Flavanols group (F) are presented. * Indicates a significant increase in BDNF mRNA levels in the anthocyanins group in comparison to control in DG, PCL, CA1 and CA3, P<0.05. No significant differences between the four diet groups were observed in the cerebral cortex. Optical density levels are shown as mean ± SEM derived from at least 6 animals per group. Representative Rnase treated sections are presented for each hippocampal region. The scale presented represents 100 µm.</p

Levels of brain-derived neurotrophic factor (BDNF) in the hippocampus.

<p>A) Dissected hippocampal tissue lysates were probed for levels of pro-BDNF and BDNF using antibodies that detect the pro-domain of the BDNF protein and the mature protein. Representative immunoblots showing protein levels in 2 animals on the control diet (C), 2 animals supplemented with 2% BB diet (BB), 2 animals supplemented with Anthocyanins Extract (A) and 2 animals supplemented with Flavanols ((−) Epicatechin and (+) Catechin) (F) are presented. Pro-BDNF (grey bars) and mature BDNF (white bars). * Indicates a significant increase in BDNF levels in Blueberry and Anthocyanins groups relative to the control group, P<0.05; n = 6. ** Indicates a significant increase in BDNF levels in Flavanols group relative to control, P<0.01, n = 6. Pro-BDNF and mature BDNF were normalized against GAPDH. B) Correlation between choice accuracy (number of correct choices) in spatial memory task after 6 weeks of dietary interventions (C, BB, A and F) and levels of hippocampal BDNF protein levels, n = 24.</p