Glutathione

Whey protein rich in alpha-lactalbumin increases the ratio of plasma tryptophan to the sum of the other large neutral amino acids and improves cognitive performance in stress-vulnerable subjects
Markus CR, Olivier B, de Haan EH. [Am J Clin Nutr. 2002 Jun;75(6):1051-6.]
The negative effect of chronic stress on performance may be mediated by reduced brain serotonin function. The uptake of the serotonin precursor tryptophan into the brain depends on nutrients that influence the availability of tryptophan by changing the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp-LNAA ratio). A diet-induced increase in tryptophan may increase brain serotonergic activity levels and improve cognitive performance, particularly in high stress-vulnerable subjects. We tested whether alpha-lactalbumin, a whey protein with a high tryptophan content, would increase the plasma Trp-LNAA ratio and improve cognitive performance in high stress- vulnerable subjects. A significantly greater increase in the plasma Trp-LNAA ratio after consumption of the alpha-lactalbumin diet than after the control diet was observed; memory scanning improved significantly only in the high stress-vulnerable subjects. The results suggest that dietary protein rich in alpha-lactalbumin improves cognitive performance in stress-vulnerable subjects via increased brain tryptophan and serotonin activities.

The bovine protein rich in alpha-lactalbumin, increases the plasma ratio of tryptophan to the other large neutral amino acids and in vulnerable subjects raises cortisol concentration and improves mood under stress.

Am J Clin Nutr 2000 June; 71(6): 1536-44.

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

J Psychopharmacol. 2006 July; 20 (4): 526-35.

Behav Brain Res. 2009 Mar 2;198(1):258-62.

Glutathione depletion in the brain disrupts short-term spatial memory in the Y-maze in rats and mice.

Dean O, Bush AI, Berk M, Copolov DL, van den Buuse M.

Mental Health Research Institute, 155 Oak Street, Parkville, Victoria 3052, Australia. oliviad@barwonhealth.org.au

Oxidative stress and reduced brain glutathione (GSH) levels have been reported in psychiatric illnesses including schizophrenia and bipolar disorder. However the role of GSH in cognitive impairment in the illness remains unclear. Treatment of Sprague-Dawley rats and C57Bl/6 mice with 2-cyclohexene-1-one (CHX) dose-dependently reduced striatal and frontal cortical GSH levels similar to those in schizophrenia. In both species, GSH depletion resulted in disruption of short-term spatial recognition memory in a Y-maze test. In conclusion, GSH depletion induces cognitive impairment, which may be relevant to the role of GSH in psychiatric illnesses.

PMID: 19061918 [PubMed - indexed for MEDLINE]