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Effects of Walnuts (Juglans regia) on Learning and Memory Functions


Walnut has been regarded as a health food that is delicious and nutritious. Both preventive and therapeutic effects of walnut are well documented. Walnuts are rich in omega-3 fatty acids that are reported to have beneficial effects on brain function. The present work was designed to evaluate the effects of walnuts on learning and memory in male rats. The effect of oral intake of walnut was also monitored on food intake. Walnut was given orally to rats for a period of 28 days. Memory function in rats was assessed by elevated plus maze (EPM) and radial arm maze (RAM). A significant improvement in learning and memory of walnut treated rats compared to controls was observed. Walnut treated rats also exhibited a significant decrease in food intake while the change in growth rate (in terms of percentage) remained comparable between the two groups. Analysis of brain monoamines exhibited enhanced serotonergic levels in rat brain following oral intake of walnuts. The findings suggest that walnut may exert its hypophagic and nootropic actions via an enhancement of brain 5-HT metabolism.

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5-hydroxy tryptamine


5-hydroxy indole acetic acid


Alpha linolenic acid


Eicosapentaenoic acid


Elevated plus maze


High performance liquid chromatography with electrochemical detection


Linoleic acid


Radial arm maze




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The authors are thankful to the University of Karachi, Pakistan for funding this project.

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Correspondence to Saida Haider.

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Haider, S., Batool, Z., Tabassum, S. et al. Effects of Walnuts (Juglans regia) on Learning and Memory Functions. Plant Foods Hum Nutr 66, 335–340 (2011).

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  • Elevated plus maze
  • Hypophagic action
  • Nootropic substance
  • Radial arm maze
  • Serotonin
  • Walnut