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The World Health Organization defines mental health (Cognitive Health) as "a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community.

Ageing is accompanied by what is normally considered to be inevitable cognitive decline, although the extent to which this occurs is highly variable, and strongly affected by various disease processes. Cognitive function is a major determinant of quality of life in older age and decline in cognitive functioning is a primary contributing factor to increasing dependency in the elderly. Due to the ageing profile of the population, the financial, social, and other burdens that this dependency places upon society are of increasing concern. Thus, finding ways to prevent or ameliorate age-related cognitive decline is a public health imperative, with potential benefits not just in terms of lessening aged care costs but also in the enhancement of well-being in a growing segment of society.

After “cardiovascular health” the second most area of research, particularly for the marine omega-3 fatty acids is cognitive performance and reducing the rate of age related cognitive decline. Several research in past, indicates that omega-3 fatty acids reduce inflammation and help prevent risk factors associated with chronic diseases such as heart disease, cancer, arthritis and cognitive health.

Essential fatty acids (omega-3) are highly concentrated in the brain and appear to be particularly important for cognitive (brain memory and performance) and behavioral function Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are one diet-related factor suggested to influence cognitive decline during ageing. The n-3 long-chain (LC) PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are crucial to brain development and normal brain functioning [1]. DHA is particularly important to brain functioning due to its influence on neural membrane properties, which modulate cell signalling [2]. DHA concentration in the brain decreases with age in humans [3] and rats [4]; this has been postulated to be consequential to the age-related deterioration in central nervous system functions [3]. Evidence from animal studies supports this; animals fed a low n-3 PUFA diet show cognitive deficits [4],[5] that are ameliorated by DHA supplementation [6], [7] and DHA supplementation improves memory performance in aged mice [8]

Some studies have suggested an association between omega-3 long-chain polyunsaturated fatty acids (n-3 LC PUFAs) and better cognitive outcomes in older adults. The main objective of the current study was to provide a comprehensive assessment of the potential of n-3 LC PUFAs to slow cognitive decline in normal elderly people, and included ApoE-ε4 allele carriage as a potential moderating factor. The detailed methodology of the trial is reported herein.

This methodology and protocol paper provides a detailed overview of the design and implementation of a double-blind, randomised, controlled trial assessing the efficacy of a DHA-rich fish-oil supplement on slowing cognitive decline, over 18-months, in cognitively-normal older adults. This is one of the few trials to date to examine the impact of n-3 LC PUFA supplementation on cognitive decline in cognitively healthy older adults.

Advantages of the current study are the comprehensive assessment of cognitive functioning and the multiple measurement points, which allow for assessment of an intervention effect on a trajectory, rather than effects at a specific time point

The significance could be wide-ranging if such an available and inexpensive dietary treatment has the possibility to safely reduce cognitive decline in ageing, given the links between cognitive functioning and the societal and personal burden of dependency and decreased quality of life in older age.


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doi:10.1186/1475-2891-10-117

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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