Neuronal depletion of omega-3 fatty acids induces flax seed dietary self-selection in the rat.

Key Findings:

In humans, psychological stress has been associated with low levels of omega 3 fatty acids in the brain. Deprivation of an omega-3 deficient diet may lead to a self-selecting dietary coping responses to correct the problem. Rats fed a diet deficient in omega-3 fatty acids acquired a preference for omega-3 fatty acids and learned to select a novel food containing omega-3 fatty acids. EPA and DHA were found to be significantly in rats fed the omega-3 fatty acid deficient diet. The study shows that deficient rats learned to choose a diet sufficient in omega 3s in a one-trial learning context, meaning that they were not trained for omega 3 selection with a prior deficiency/repletion cycle. Although the mechanisms for the findings is not known, it may involve the ratio of omega-3 to omega-6 fatty acids that may influence serotoninergic and catecholaminergic neurotransmission.

ABSTRACT:

The impact of essential dietary fatty acid deficiency on self-selection of fatty acid enriched foods is little studied in spite of widespread health promotion claims for fatty acid supplemented diets. Accordingly, the present studies investigated the consequences of consumption over four weeks of omega-3 fatty acid replete and deficient diets on dietary fatty acid self-selection and brain lipid composition in rats. Dietary omega-3 fatty acid deficiency produced correspondingly low levels (50–55 % decrease) of omega-3 fatty acids in the forebrain relative to rats consuming an omega-3 fatty acid replete diet. The state of omega-3 fatty acid deficiency generated a robust preference for consumption of an omega-3 fatty acid replete diet. Moreover, omega-3 fatty acid self-selection developed slowly and was not present in rats maintained on laboratory chow diet suggesting that post-ingestive nutritional cues, rather than taste, odor or texture cues, were employed in guiding the preference for the omega-3 fatty acid enriched diet. These results provide evidence for the ability of rats with declining brain levels of omega-3 fatty acids to detect a dietary deficiency of this essential class of lipids and to identify and consume a food source capable of restoring fatty acid repletion. (Author’s abstract)