The effect of grapefruit juice on the urinary 6β-hydroxycortisolicortisol ratio was investigated in healthy volunteers. The urinary concentration of cortisol was virtually unaffected by the administration of grapefruit juice whereas the concetration of 6β-hydroxycortisol in the urine decreased when grapefruit juice was given every 3 hours. The administration of grapefruit juice was thus considered to result in a decrease in the urinary 6β-hydroxycortisol/cortisol ratio. In addition, both diurnal and individual differences were also observed in the extent of the inhibitory effect of grapefruit juice.
No takes yet. Share an insight, caveat, or question.
Nakamura et al. (1997) studied this question.