Last weekend (18/05/08) The Sunday Times ran a story entitled “Superfood celery combats brain diseases”.  Quite timely I thought, as I was in the middle of preparing a post on the important role that dietary flavonoids , also known as bioflavonoids  (a group of over 4000 types of polyphenol plant compounds), play in maintaining mental health e.g. memory, learning and general mental performance.  The newspaper article focussed on the flavonoids, luteolin and diosmin, found in celery and how they may be important in slowing the progress of brain diseases such as Alzheimer’s disease.

A recently published medical review paper(1) brought together evidence for the role of dietary derived flavonoids and mental health.  In this paper Dr Jeremy Spencer, a researcher and lecturer at my old University, highlights a number of studies in both humans and animals which have found that flavonoids, from a variety of dietary sources such as grapes, tea, blueberries, cocoa, onions, broccoli and tomatoes (to name but a few), have beneficial effects on cognitive (mental) performance.  He postulates that the benefits come from the ability of the flavonoids to protect brain neurones, reduce neuronal inflammation, enhance neuronal function and even stimulate neuronal regeneration (regrowth). 

The paper is extensive, however I would just like to mention one study that is reviewed(2).  In this study 1640 individuals, all over the age of 65, were followed for ten years and their dietary habits assessed over that time.  All of them were free of dementia at the start of the study.  Cognitive (mental) performance was examined four times over the ten year period.  Flavonoid intake was associated with a significantly better cognitive performance at the start of the study and throughout the study period.  The individuals with the highest flavonoid intakes were found to have better preservation of mental performance with ageing than subjects with the lowest intakes of flavonoids.  After 10 years the individuals with the lowest intakes were found to have lost an average of 2.1 points on a test of mental performance (the Mini-Mental State Examination) compared to those with the highest intakes who had lost on average only 1.2 points.  Such data provides a strong indication that regular dietary flavonoid consumption may have a positive effect on preserving mental performance with ageing.

As Dr Susanne Sorensen of the Alzheimers Society is quoted as saying in the newspaper “we know a healthy balanced diet can reduce dementia risk.  This work reinforces the need to eat a diet rich in fruits and vegetables”.  There are many dietary factors which can contribute to a healthy brain and positive mood and I am sure that I will address these factors in my future writings!

It is clear that a diet rich in a variety of different vegetables and fruits is really very important for all aspects of health.  There is NO substitute for a diet plentiful in a variety of vegetables and fruits.  Choosing produce with a mixture of colours will provide an array of different flavonoids.  Flavonoid supplements do exist and these may be helpful to take in addition to a healthy diet as a means of boosting intakes.  If you do choose to take a supplement look out for one that provides an assortment of many different flavonoids (they may be labelled as bioflavonoids).

(1) Spencer JPE.  2008.  Food for thought: the role of dietary flavonoids in enhancing human memory, learning and neuro-cognitive performance.  Proceedings of the Nutrition Society.  67:238-252
(2) Letenneur L et al.  2007.  Flavonoid intake and cognitive decline over a 10 year period.  Am J Epidemiol.  165:1364-1371

Written by Ani Kowal