Effects of Milk Casein-derived Peptides on Absolute Oxyhaemoglobin Concentrations in the Prefrontal Area and on Work Efficiency after Mental Stress Loading in Male Students

Abstract

This study examined the influence of milk casein-derived peptides on cerebral activity after mental stress loading. In a crossover study, 16 male students were given a drink containing peptides (peptide group), or water (control group) before stress loading. The oxyhaemoglobin (HbO₂) concentration in the prefrontal area of the brain and work efficiency were measured as indicators of cerebral activity and differences in these parameters were examined according to type A or type B personality. Type A behaviour was defined as: aggression–hostility, hard-driving—time-urgency and speed–power, whereas type B behaviour did not have these characteristics. Peptide intake resulted in a significant increase in both HbO₂ concentration and work efficiency, whilst a similar increase was not seen in the control group. When divided into type A or type B personality, the changes in HbO₂ concentration for the control group differed significantly in the right prefrontal area. Moreover, in type A subjects the HbO₂ concentration in the right prefrontal area following intake was significantly different between the peptide and control groups.

Keywords

Milk casein-derived peptides Type A behaviour pattern Near-infrared time-resolved spectroscopy Cerebral activity Mental stress Oxyhaemoglobin

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