Nutrigenomic explanation for the beneficial effects of fish oil on cognitive function

36 Ridgewood Circle
Wilmington, DE 19809
E-mail: celiamaryross{at}aol.com

Dear Sir:

Whalley et al (1) analyzed subjects' erythrocyte fatty acid profiles and compared these with measures of cognitive function. Various correlations indicated that n–3 fatty acids in the diet are associated with better cognitive performance in old age. The authors discussed possible reasons for this. They addressed confounding variables such as the likely overall healthier diet of those who consume more n–3 fatty acids. They also examined 2 mechanisms by which n–3 fatty acids might maintain cognitive function in adults as they age. n–3 Fatty acids are beneficial to vascular health and may forestall cerebrovascular disease and thus dementia. Also, a lower ratio of n–6 to n–3 fatty acids may promote a healthier balance of eicosanoids, which would protect membrane function.

A third, nutrigenomic mechanism might work in conjunction with the first 2. Diets rich in n–3 fatty acids alter gene expression in the brain (2–4). Genes whose expression is altered include those involved in controlling synaptic plasticity, cytoskeleton and membrane association, ion channel formation, signal transduction, and energy metabolism and in counteracting the appearance of amyloid aggregates (2, 3). Fish oil induces the transcription of the gene for prealbumin (3). Prealbumin sequesters amyloid ß-polypeptide, keeping it from forming the aggregates that are a characteristic of Alzheimer disease (3, 4). Thus, fish oil consumption might encourage gene expression conducive to brain maintenance during aging. This might be one reason Whalley et al found that their subjects' erythrocyte fatty acid profiles were related to cognitive function at the age of 64 y.

ACKNOWLEDGMENTS

The author had no conflicts of interest to report.

REFERENCES

1. Whalley LJ, Fox HC, Wahle KW, et al. Cognitive aging, childhood intelligence, and the use of food supplements: possible involvement of n–3 fatty acids. Am J Clin Nutr 2004;80:1650–7.
2. Kitajka K, Puskas LG, Zvara A, et al. The role of n–3 polyunsaturated fatty acids in brain: modulation of rat brain gene expression by dietary n–3 fatty acids. Proc Natl Acad Sci U S A 2002;99:2619–24.
3. Puskas LG, Kitajka K, Nyakas C, et al. Short-term administration of omega 3 fatty acids from fish oil results in increased transthyretin transcription in old rat hippocampus. Proc Natl Acad Sci U S A 2003;100:1580–5.
4. Kitajka K, Sinclair AJ, Weisinger RS, et al. Effects of dietary omega-3 polyunsaturated fatty acids on brain gene expression. Proc Natl Acad Sci U S A 2004;101:10931–6.