Background and aims: Kiwifruit contains bioactive substances that may lower blood pressure (BP) and improve endothelial function. We examined the effects of adding kiwifruit to the usual diet on 24-h ambulatory BP, office BP and endothelial function.

Methods: In a parallel-groups study, 118 subjects with high normal BP or stage 1 hypertension (systolic BP 130-159 mmHg and/or diastolic BP 85-99 mmHg) were randomized to intake of three kiwifruits (intervention) or one apple (control) a day for 8 weeks. Office and 24-h ambulatory BP was measured along with biomarkers of endothelial function including metabolites of nitric oxide (NO) formation and finger photo-plethysmography.

Results: At randomization, mean 24-h ambulatory systolic/diastolic BP was 133 ± 13/82 ± 9 mmHg (n = 106). After 8 weeks, BP was lower in the group assigned to kiwifruit versus apple intake (between group difference, - 3.6 mmHg [95% CI - 6.5 to - 0.7], p = 0.017 and - 1.9 mmHg [95% CI - 3.6 to - 0.3]; p = 0.040, for systolic and diastolic BP, respectively). Changes in office BP and endothelial function did not differ between the groups.

Conclusions: Among men and women with moderately elevated BP, intake of three kiwifruits was associated with lower systolic and diastolic 24-h BP compared with one apple a day. The effect may be regulated by mechanisms other than improvement of endothelial function.