The effect of kiwifruit consumption on blood pressure in subjects with moderately elevated blood pressure: A randomized, controlled study

Abstract

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.

Key Words::

• Ambulatory blood pressure
• endothelial function
• NO formation

Acknowledgements

We thank the subjects for their participation. We thank Lise Bergengen for help with the office and endothelial function measurements, Ragnhild Kleve for the 24-h BP measurements, Benedicte Olsen Høvding and Kristin Elisabeth Ruud Lode for study management and dietary calculations and Nicole Warmbrot for establishing the database. KIWI^®, a widespread food store chain in Norway, provided both apples and kiwifruits for the study. A grant given by the Throne Holst foundation provided support for laboratory analyses. Clin. Trial Gov.: NCT00948363.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.