Editors' ChoiceNeuroscience

The Food for Mood

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Science Translational Medicine  16 Mar 2011:
Vol. 3, Issue 74, pp. 74ec35
DOI: 10.1126/scitranslmed.3002362

Over the past two centuries, Western civilization has transformed humankind with stunning contributions such as ... the triple cheeseburger. Our dietary ratio of polyunsaturated fatty acids (omega-6 to omega-3) is on the rise, which has been associated with heart disease, cancer, and even psychiatric disorders. A recent study by Lafourcade and colleagues establishes a link between nutritional deficiencies in omega-3 fatty acids and signaling lipids called “endocannabinoids” that can regulate behavior and mood.

The endocannabinoid system links food lipids, synaptic activity in the brain, and behavior. To investigate how polyunsaturated fatty acids disrupt synaptic activity, Lafourcade et al. generated a mouse model of malnutrition by administering a diet of oils, either rich or poor in omega-3 fatty acids but equal in calories. Restricting dietary omega-3 fatty acids from the prenatal period onward decreased omega-3 levels in the brain. The prefrontal cortex, which is important for executive function and emotion, and the nucleus accumbens, which is involved in reward and motivation, were then examined. In the omega-3–deficient mice, both regions of the brain showed altered synaptic plasticity (the ability to change in response to use or disuse) that was specific for the endocannabinoid system. The authors noted an uncoupling of the endocannabinoid receptor CB1R—the most abundant G protein–coupled receptor in the central nervous system—from its effector G proteins. This finding was restricted to the prefrontal cortex and the nucleus accumbens of omega-3–deficient mice, suggesting a brain-region–specific mechanism for altered plasticity. The authors further confirmed that, compared with controls, an omega-3–deficient diet resulted in depressed mice, as evidenced by an increase in time spent immobile, higher anxiety, and less social exploration. An antidepressant, imipramine, reversed some of these behaviors.

This study demonstrates that nutritional deficiencies can disrupt endocannabinoid-mediated plasticity in brain regions important for emotional regulation, in association with behavioral abnormalities. The findings have mechanistic and epidemiological implications for the role of diet in mood control. Health lesson learned? Eat more salmon!

M. Lafourcade et al., Nutritional omega-3 deficiency abolishes endocannabinoid-mediated neuronal functions. Nat. Neurosci. 14, 345–350 (2011). [Abstract]

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