Abstract
Chronic stress has a negative influence on health. The aim was to determine stress reducing effects of yoghurt enriched with bioactive components as compared to normal yoghurt. High-trait anxiety individuals (n = 67) aged 18–63 years participated in a randomized, placebo-controlled, double-blinded intervention with parallel groups. They received either yoghurt enriched with alpha-lactalbumin, casein tripeptides and B vitamins (active) or isoenergetic standard yoghurt (control). To detect changes in psychological and physiological stress, State-Trait Anxiety Inventory, Profile of Mood States, salivary cortisol, inflammatory markers, blood pressure, heart rate variability (HRV) and actigraphy were monitored. We observed higher ratings of vigor (p = 0.047) and reduced feeling of inefficiency (p = 0.048) in the active group. HRV (baseline adjusted mean 49.1 ± 2.3 ms) and recovery index (106.6 ± 33.4) were higher in the active group than in controls (42.5 ± 2.2 ms and 80.0 ± 29.3) (p = 0.046 and p = 0.02, respectively). In conclusion, daily intake of yoghurt enriched with bioactive components may aid in stress coping.
Acknowledgements
The authors wish to thank Dr. Riikka Nevala, MD for medical consulting and Dr. Pia Bäckström for her contribution to the study design. Authors thank Mrs. von Behr for her valuable assistance in clinical visits and laboratory. We also thank technical assistants Ms. Raatikainen, Ms. Eskelinen, Ms. Salminen and Ms. Pitkänen at Institute of Biomedicine for helping in the laboratory and Firstbeat Technologies Ltd for their support in completing the study measurements and Valio Ltd R&D for providing the study products. We are grateful to all volunteers for their participation.