RESUMO
BACKGROUND & AIMS: Effects of nutritional supplements on psychological wellbeing receive increasing attention. This double-blind placebo-controlled study investigated effects of a four week intake of powder of fertilized eggs (Young Tissue Extract; YTE) in a laboratory protocol (Trier Social Stress Test; TSST). METHODS: Aside the laboratory stress test, we examined differential effects on subjects with high and low levels of chronic stress. Thus, subjects were further divided into two subgroups with scores for chronic stress scores below and above average, respectively. RESULTS: Compared to placebo, a four week intake of YTE did not result in superior effects on general wellbeing. However, beneficial effects of YTE were observed in subjects with enhanced levels of chronic stress. When compared to placebo these subjects showed an improvement of both the psychological and endocrine stress response. CONCLUSIONS: Group differences suggest that YTE selectively improves adaptation to acute stress by normalizing the endocrine and the subjective stress response. Subjects with less chronic stress also reported less subjective stress but did not show beneficial effects on the endocrine stress response.