Less Stress: Grape seed extract improves blood pressure
Polyphenols may help lower perceived stress levels
This study followed 80 healthy men and women, aged 40 to 70, with mildly elevated systolic blood pressure between 125 and 140 mmHg. Body mass index scores ranged from 19 to 32, and all the women were postmenopausal. Participants measured blood pressure for seven days before taking a placebo or 300 mg of grape seed extract per day.
Until the fourth week, women in the placebo group saw a greater reduction in systolic blood pressure than men in the placebo group. After 16 weeks, systolic and diastolic blood pressure had declined in both groups, but declined more for those taking grape seed extract. Men saw the most significant benefit, with systolic blood pressure declining 4.6 mmHg, and diastolic pressure declining 3.2 mmHg by the end of the study.
Those taking grape seed extract perceived less worry, tension, and demands and reported greater joy compared to placebo, with women experiencing greater benefits than men.
Reference: Nutrients; 2021, Vol. 13, No. 2, 654
Calm: L-theanine relaxed healthy adults
Stress-hormone cortisol levels decreased
Humans use the stress response to survive threats, and to help achieve challenging goals, but chronic stress can have negative health effects. In this study, 15 healthy adults reporting moderate levels of stress took a placebo or a single 200 mg dose of L-theanine, pausing for a week, then switching supplement and placebo groups.
To induce stress, doctors gave a mental math test before, and 45 minutes after, the supplement. Blood pressure and heart rate increased during the math test, with participants reporting greater levels of stress and anxiety. Three hours after taking L-theanine, alpha power brain wave activity—typical of relaxation, meditation, and deep sleep—increased in the frontal region of the brain. Researchers also saw salivary cortisol levels decrease following the math test in the L-theanine group, suggesting reduced stress.
Doctors pointed out the study took place during the Covid-19 pandemic, which negatively affected worldwide population physical and mental health.
Reference: Neurology and Therapy, 2021, Vol. 10, 1061-78
