Lysine fortification reduces anxiety and lessens stress in family members in economically weak communities in Northwest Syria

Proc Natl Acad Sci U S A. 2004 Jun 1;101(22):8285-8. doi: 10.1073/pnas.0402550101. Epub 2004 May 24.


Lysine is a limiting amino acid in diets based on wheat as the staple. In experimental animals, prolonged dietary lysine inadequacy increases stress-induced anxiety. If observed in humans, such a result would have a strong implication for the relationship between nutrition and communal quality of life and mental health. As part of a 3-month randomized double-blind study, we tested whether lysine fortification of wheat reduces anxiety and stress response in family members in poor Syrian communities consuming wheat as a staple food. In the lysine-fortified group, the plasma cortisol response to the blood drawing as a cause of stress was reduced in females, as was sympathetic arousal in males as measured by skin conductance. Lysine fortification also significantly reduced chronic anxiety as measured by the trait anxiety inventory in males. These results suggest that some stress responses in economically weak populations consuming cereal-based diets can be improved with lysine fortification.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Anxiety / drug therapy*
  • Bread
  • Child
  • Diet
  • Double-Blind Method
  • Economics*
  • Female
  • Food, Fortified*
  • Humans
  • Hydrocortisone / blood
  • Lysine / administration & dosage
  • Lysine / therapeutic use*
  • Male
  • Quality of Life
  • Residence Characteristics
  • Stress, Psychological / drug therapy*
  • Surveys and Questionnaires
  • Syria
  • Triticum / chemistry*


  • Lysine
  • Hydrocortisone