A randomized controlled trial of high dose ascorbic acid for reduction of blood pressure, cortisol, and subjective responses to psychological stress

Rationale: Physiological responses to stress are considered disruptive to health. High-dose ascorbic acid has reduced indices of stress in laboratory animals. Methods: We conducted a randomized double-blind, placebo-controlled 14-day trial of sustained-release ascorbic acid (60 healthy young adults; 3×1000 mg/day Cetebe) and placebo (60 healthy young adults) for reduction of blood pressure, cortisol, and subjective response to acute psychological stress (Trier Social Stress Test, TSST, consisting of public speaking and mental arithmetic). Six subjects from each group were excluded. Results: Compared to the placebo group, the ascorbic acid group had less systolic blood pressure (an increase of 23 versus 31 mmHg), diastolic blood pressure, and subjective stress responses to the TSST; and also had faster salivary cortisol recovery (but not smaller overall cortisol response). Cortisol response to 1 µg ACTH, and reported side-effects during the trial did not differ between groups. Plasma ascorbic acid level at the end of the trial but not pre-trial was associated with reduced stress reactivity of systolic blood pressure, diastolic blood pressure, and subjective stress, and with greater salivary cortisol recovery. Conclusions: Treatment with high-dose sustained-release ascorbic acid palliates blood pressure, cortisol, and subjective response to acute psychological stress. These effects are not attributable to modification of adrenal responsiveness.