Diet rich in alpha-lactalbumin improves memory in unmedicated recovered depressed patients and matched controls

J Psychopharmacol. 2006 Jul;20(4):526-35. doi: 10.1177/0269881105057466. Epub 2005 Sep 20.


Depression is associated with reduced brain serotonin (5-hydroxytryptamine; 5-HT) function and with cognitive dysfunctions. A diet rich in alpha-lactalbumin protein has been found to increase the ratio tryptophan /large neutral amino acids (Trp/SigmaLNAA), and to improve cognitive functioning in individuals with high neuroticism scores. Since cognitive dysfunctions sometimes persist after remission of depression, the present study investigated the effects of alpha-lactalbumin-enriched diet on cognition in recovered depressed patients. Twenty-three recovered depressed patients and 20 healthy matched controls without a history of depression consumed meals rich in alpha-lactalbumin or casein protein in a double-blind crossover design. Mood, cognitive function and plasma amino acids were assessed at both sessions before and after dietary intake. Alpha-lactalbumin protein had no effect on mood, but improved abstract visual memory and impaired simple motor performance. These effects were independent of history of depression. Supplements of lactalbumin may be useful for nutrition research in relation to age- or disease-related memory decline. The present findings should be further examined in different (e.g. medicated) samples. The long-term effects of alpha-lactalbumin should also be investigated.

Publication types

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

MeSH terms

  • Adult
  • Affect / drug effects
  • Amino Acids / metabolism
  • Cognition / drug effects
  • Depression / psychology*
  • Diet*
  • Female
  • Humans
  • Lactalbumin / pharmacology*
  • Male
  • Memory / drug effects*
  • Neuropsychological Tests
  • Personality Tests
  • Psychiatric Status Rating Scales
  • Psychomotor Performance / drug effects
  • Reaction Time / drug effects
  • Recognition, Psychology / drug effects


  • Amino Acids
  • Lactalbumin