Tuesday, July 31, 2012

Omega-3 Fats Increase Resilience to Stress


This study on the health benefits of omega-3 fats on increasing resilience to stress was done with rats, but I have little doubt that there are similar benefits for human beings as well. The new study was published on the open source PLOS ONE site, which now capitalizes the "o" in their title (used to be PLoS ONE), which I guess is a step up in the world.

Take Home Info:
  • The adult rats were fed, from conception, (1) omega-3 deficient diet, (2) control diet, or (3) omega-3 enriched diet.
  • The control diet was high in alpha-linoleic acid (an omega-3 precursor found in flax oil and other plants), but not in preformed long-chain omega-3 fatty acids (DHA, EPA).
  • They evaluated the impact of repeated restraint stress (6 hours/day for 21 days) on the adult rats.
  • The rats fed a control diet lost weight (a stress response), had increased plasma corticosterone (stress hormone), and showed moderate behavioral changes, with increases only in grooming (a stress behavior) and increased entries into the open arms (Elevated-Plus Maze test, which measures anxiety levels). 
  • Rats fed the omega-3 enriched diet had a lower stress-induced weight loss, lower plasma corticosterone peak, and reduced grooming.
  • Rats chronically lacking omega-3 fatty acid exhibited an increased startle response, a stress-induced decrease in loco-motor activity ("giving up"), and exaggerated grooming.

What this study shows: 
  • Omega-3 fats help rats deal with intense stress more effectively
  • ALA does not perform as well (so fish oil is better than flax oil)

Here is the abstract and link for those who want to read this paper.

Influence of Omega-3 Fatty Acid Status on the Way Rats Adapt to Chronic Restraint Stress

Marie Hennebelle1, Laure Balasse2,3, Alizée Latour1, Gaelle Champeil-Potokar1, Stéphanie Denis1, Monique Lavialle1, Pascale Gisquet-Verrier2,3, Isabelle Denis1, Sylvie Vancassel1*

1 INRA, Unité de Nutrition et Régulation Lipidiques des Fonctions Cérébrales, NuRéLiCe, UR909, Domaine de Vilvert, Jouy en Josas, France, 2 CNRS, Centre de Neurosciences Paris-Sud, Univ Paris-Sud UMR 8195, Orsay, France, 3 Université Paris-Sud, UMR 8195, Orsay, France

Abstract

Omega-3 fatty acids are important for several neuronal and cognitive functions. Altered omega-3 fatty acid status has been implicated in reduced resistance to stress and mood disorders. We therefore evaluated the effects of repeated restraint stress (6 h/day for 21 days) on adult rats fed omega-3 deficient, control or omega-3 enriched diets from conception. We measured body weight, plasma corticosterone and hippocampus glucocorticoid receptors and correlated these data with emotional and depression-like behaviour assessed by their open-field (OF) activity, anxiety in the elevated-plus maze (EPM), the sucrose preference test and the startle response. We also determined their plasma and brain membrane lipid profiles by gas chromatography. Repeated restraint stress caused rats fed a control diet to lose weight. Their plasma corticosterone increased and they showed moderate behavioural changes, with increases only in grooming (OF test) and entries into the open arms (EPM). Rats fed the omega-3 enriched diet had a lower stress-induced weight loss and plasma corticosterone peak, and reduced grooming. Rats chronically lacking omega-3 fatty acid exhibited an increased startle response, a stress-induced decrease in locomotor activity and exaggerated grooming. The brain omega-3 fatty acids increased as the dietary omega-3 fatty acids increased; diets containing preformed long-chain omega-3 fatty acid were better than diets containing the precursor alpha-linolenic acid. However, the restraint stress reduced the amounts of omega-3 incorporated. These data showed that the response to chronic restraint stress was modulated by the omega-3 fatty acid supply, a dietary deficiency was deleterious while enrichment protecting against stress.

Citation: Hennebelle M, Balasse L, Latour A, Champeil-Potokar G, Denis S, et al. (2012) Influence of Omega-3 Fatty Acid Status on the Way Rats Adapt to Chronic Restraint Stress. PLoS ONE 7(7): e42142. doi:10.1371/journal.pone.0042142



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