Food and Behaviour Research

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Omega-3 fatty acids, energy substrates, and brain function during aging

Freemantle E, Vandal M, Tremblay-Mercier J, Tremblay S, Blachere JC, Begin ME, Thomas Brenna J, Windust A, Cunnane SC.  (2006) Prostaglandins Leukot Essent Fatty Acids. Jul 6; [Epub ahead of print]  

Web URL: View this and related abstracts via PubMed here


The maintenance of optimal cognitive function is a central feature of healthy aging. Impairment in brain glucose uptake is common in aging associated cognitive deterioration, but little is known of how this problem arises or whether it can be corrected or bypassed.

Several aspects of the challenge to providing the brain with an adequate supply of fuel during aging seem to relate to omega-3 fatty acids. For instance, low intake of omega-3 fatty acids, especially docosahexaenoic acid (DHA), is becoming increasingly associated with several forms of cognitive decline in the elderly, particularly Alzheimer's disease.

Brain DHA level seems to be an important regulator of brain glucose uptake, possibly by affecting the activity of some but not all the glucose transporters. DHA synthesis from either alpha-linolenic acid (ALA) or eicosapentaenoic acid (EPA) is very low in humans begging the question of whether these DHA precursors are likely to be helpful in maintaining cognition during aging.

We speculate that ALA and EPA may well have useful supporting roles in maintaining brain function during aging but not by their conversion to DHA. ALA is an efficient ketogenic fatty acid, while EPA promotes fatty acid oxidation.

By helping to produce ketone bodies, the effects of ALA and EPA could well be useful in strategies intended to use ketones to bypass problems of impaired glucose access to the brain during aging. Hence, it may be time to consider whether the main omega-3 fatty acids have distinct but complementary roles in brain function.


This review focuses on the potential role of omega-3 fatty acids in brain energy metabolism - and specifically, their ability to increase the availability of ketones, which the brain can use as an alternative to glucose.

Increasing evidence shows that brain glucose uptake is impaired in older adults with cognitive decline and dementia, and ketone bodies provide an alternative source of fuel that may help to compensate for this 'energy deficit'

As the authors explain, while there is evidence that omega-3 DHA can enhance brain glucose uptake, production of ketones is enhanced by other omega-3 fatty acids such as ALA and EPA.