The effect of docosahexaenoic acid on plasma catecholamine concentrations and glucose tolerance during long-lasting psychological stress: A double-blind placebo-controlled study

Shigeki Sawazaki, Tomohito Hamazaki, Kazunaga Yazawa, Masashi Kobayashi

Research output: Contribution to journalArticle

45 Citations (Scopus)


We previously found that docosahexaenoic acid (DHA) intake prevented aggression from increasing at times of mental stress. In the present study, we investigated whether DHA intake modified the plasma catecholamines and cortisol of medical students during a 9-wk period of final exams. We also investigated the effects of DHA intake on a 75g oral glucose tolerance test (oGTT). Fourteen medical students participated in the present study. They were randomly allocated to either control or DHA group in a double-blind manner. Subjects in the control group (4 males and 3 females) took 10 control capsules/d, each capsule containing 280 mg of mixed plant oil, and those in the DHA group (4 males and 3 females) took 10 DHA capsules/d containing 1.5 g DHA for 9wk, during which subjects underwent more than 20 stressful final exams. At the start and end of the study, plasma catecholamines (epinephrine, norepinephrine (NE) and dopamine) and cortisol were measured; a 75g oGTT was also performed. There were no intra-or intergroup differences in plasma glucose concentrations. However, NE concentrations were significantly reduced after DHA administration (-31%, p< 0.03). The other catecholamines and cortisol did not change significantly. The plasma ratio of epinephrine to NE increased in every DHA subject (+78%, p<0.02), and intergroup differences were significant (p<0.03). We conclude that these effects of DHA may be applied to people under long-lasting psychological stress to prevent stress- related diseases.

Original languageEnglish
Pages (from-to)655-665
Number of pages11
JournalJournal of Nutritional Science and Vitaminology
Issue number5
Publication statusPublished - 1999
Externally publishedYes



  • Docosahexaenoic acid
  • Epinephrine
  • Fatty acid composition
  • Norepinephrine
  • Psychological stress

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this