Many individuals would like to live to a ripe old age, but at the same time dread the thought of losing their mental capabilities as they do this. One nutritional strategy that may well have some merit in preserving the function of the ageing brain is to ensure a good intake of omega-3 fats, especially docosahexaenoic acid (DHA). There is some evidence linking higher intakes of this specific fat with lower risk of dementia. See here for more on this.
Another dietary strategy that worth considering is to keep, generally speaking, blood sugar levels on an even keel. There is evidence linking impaired blood sugar control (including diabetes) with an increased risk of brain function impairment in later life. I discussed some of this research in a previous blog post earlier this year.
More recently a study has been published which, I think, again reminds us of the potential importance of blood sugar control in brain function [1]. The study was conducted at the Columbia University Medical Center in the USA, and involved magnetic resonance imaging (MRI) scans of the brains of both humans and animals (monkeys and mice). In the first part of the study, human scans were used to identify a part of the brain that is involved in memory and is prone to damage in diabetics (known as the ‘dentate gyrus’). Animal studies then confirmed that elevated blood sugar is a potential cause of damage to the dentate gyrus.
This research is important as it suggests another mechanism by which raised blood sugar levels can impair memory in the ageing brain. However, it should be borne in mind, I think, that raised blood sugar levels might lead to cognitive decline through more than once mechanism. For instance, raised blood sugar levels will also increased the risk of something known as ‘vascular dementia’ (a situation caused, essentially, by narrowing and perhaps complete blockage in the vessels supplying blood to the brain).
Reports of this study have had one of the authors of this study, Scott Small, advocating exercise as a means to maintaining health blood sugar control. This seems eminently sensible to me. However, of course other ways of achieving this end might be to eat a diet of low glycaemic load or perhaps generally low in carbohydrate.
References:
1. Wu W, et al. The brain in the age of old: The hippocampal formation is targeted differentially by diseases of late life. Ann Neurol 2008;64:698-706