Tranquililty through fish oil

January 02, 2010

While not directly capable of giving you zen tranquility, the omega-3 essential fatty acids commonly found in fatty fish and algae seem to play an essential role in neural processing that helps animals avoid sensory overload.

Anchovies and Sardines

In a new study published in the journal Behavioral Neuroscience mice were challenged by startling them with loud noises. Those fed a diet high in the two omega-3 fatty acids – docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) – showed a markedly calmer reaction. The researchers attribute this to improved nervous system processing in those mice fed a diet high in omega-3 fatty acids and speculate this may be due to improved maintenance of nerve-cell membranes.

The body cannot make these essential nutrients from scratch. It gets them by metabolizing their precursor, α-linolenic acid (LNA), or from foods or dietary supplements with DHA and EPA in a readily usable form. "Humans can convert less than one percent of the precursor into DHA, making DHA an essential nutrient in the human diet," added Irina Fedorova, PhD, one of the paper's co-authors. EPA is already known for its anti-inflammatory and cardiovascular effects, but DHA makes up more than 90 percent of the omega-3s in the brain (which has no EPA), retina and nervous system in general.

In the study, the researchers fed four different diets with no or varying types and amounts of omega-3s to four groups of pregnant mice and then their offspring. They measured how the offspring, once grown, responded to a classic test of nervous-system function in which healthy animals are exposed to a sudden loud noise. Normally, animals flinch. However, when they hear a softer tone in advance, they flinch much less. It appears that normal nervous systems use that gentle warning to prepare instinctively for future stimuli, an adaptive process called sensorimotor gating.

Only the mice raised on DHA and EPA, but not their precursor of LNA, showed normal, adaptive sensorimotor gating by responding in a significantly calmer way to the loud noises that followed soft tones. The mice in all other groups, when warned, were startled nearly as much by the loud sound. When DHA was deficient, the nervous system most obviously did not downshift. That resulted in an abnormal state that could leave animals perpetually startled and easily overwhelmed by sensory stimuli.



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