The effects of a diet enriched with alpha-lactalbumin on mood and cortisol response in unmedicated recovered depressed subjects and controls.
Alpha-lactalbumin is a tryptophan-rich protein fraction. A diet enriched with alpha-lactalbumin increases the ratio of tryptophan to the other large neutral amino acids, which may in turn increase brain serotonin content. In stress-vulnerable individuals, alpha-lactalbumin improved mood and attenuated the cortisol response after experimental stress. The aim of the present study was to investigate the effects of an alpha-lactalbumin-enriched diet on mood and stress response in recovered depressed subjects and healthy controls. Forty-three subjects (twenty-three recovered depressed and twenty healthy subjects) received alpha-lactalbumin and casein (placebo) on separate days, in a double-blind randomised crossover design. On both occasions, subjects underwent a stress test (an unsolvable mental arithmetic task with loud noise). The stress test affected mood in both conditions. Although the alpha-lactalbumin diet led to the expected rises in tryptophan and tryptophan:large neutral amino acids ratio, only minimal effects were found on mood and cortisol response to experimental stress. The results were the same for recovered depressed patients and controls. A 1 d diet enriched with alpha-lactalbumin is not sufficient to prevent a stress-induced mood deterioration or a cortisol response in unmedicated, recovered depressed subjects. Future studies may investigate the effects of longer-term diets or may investigate different samples (e.g. medicated patients).
Merens
Wendelien
W
Department of Psychology, Leiden University, Leiden, The Netherlands.
Booij
Linda
L
Markus
Rob
R
Zitman
Frans G
FG
Onkenhout
Willem
W
Van der Does
A J Willem
AJ
D000328:Adult; D000339:Affect; D000596:Amino Acids / Q000097:blood; D000704:Analysis of Variance; D016022:Case-Control Studies; D018592:Cross-Over Studies; D003863:Depression / Q000178:diet therapy* / Q000378:metabolism / Q000523:psychology; D004032:Diet; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000097:blood*; D007768:Lactalbumin / Q000008:administration & dosage* / Q000097:blood; D008297:Male; D012463:Saliva / Q000737:chemistry; D018709:Statistics, Nonparametric; D014364:Tryptophan / Q000097:blood
D000596:Amino Acids; D014364:Tryptophan; D007768:Lactalbumin; D006854:Hydrocortisone