Voluntary liquorice ingestion increases blood pressure via increased volume load, elevated peripheral arterial resistance, and decreased aortic compliance

Elina J Hautaniemi,Mika Kähönen,Antti J Tikkakoski,Marko Uitto,Kalle Sipilä,Onni Niemelä,Jukka Mustonen,Ilkka H Pörsti,Anna M Tahvanainen,Jenni K Koskela

doi:10.1038/s41598-017-11468-7

Elina J Hautaniemi, Mika Kähönen + Show 8 more

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https://doi.org/10.1038/s41598-017-11468-7

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Abstract

We investigated the haemodynamic effects of two-week liquorice exposure (glycyrrhizin dose 290–370 mg/day) in 22 healthy volunteers during orthostatic challenge. Haemodynamics were recorded during passive 10-minute head-up tilt using radial pulse wave analysis, whole-body impedance cardiography, and spectral analysis of heart rate variability. Thirty age-matched healthy subjects served as controls. Liquorice ingestion elevated radial systolic (p < 0.001) and diastolic (p = 0.018) blood pressure and systemic vascular resistance (p = 0.037). During orthostatic challenge, heart rate increased less after the liquorice versus control diet (p = 0.003) and low frequency power of heart rate variability decreased within the liquorice group (p = 0.034). Liquorice intake increased central pulse pressure (p < 0.001) and augmentation index (p = 0.002) supine and upright, but in the upright position the elevation of augmentation index was accentuated (p = 0.007). Liquorice diet also increased extracellular fluid volume (p = 0.024) and aortic to popliteal pulse wave velocity (p = 0.027), and aortic characteristic impedance in the upright position (p = 0.002). To conclude, in addition to increased extracellular fluid volume and large arterial stiffness, two weeks of liquorice ingestion elevated systemic vascular resistance and augmentation index. Measurements performed at rest may underestimate the haemodynamic effects of liquorice ingestion, as enhanced central wave reflection and reduced chronotropic response were especially observed in the upright position.

Highlights

The mineralocorticoid receptor (MR)[1] and the glucocorticoid receptor (GR)[2] play an important role in the regulation of blood pressure (BP)
At week 0, there were no differences in radial systolic and diastolic BP (Fig. 1), heart rate (HR) (Fig. 2), aortic pulse pressure (PP), augmentation index (AIx) and aortic characteristic impedance (Fig. 3), or SVRI (Fig. 4) during the 10-min recordings between the groups
In line with these views, our previous findings indicated that the elevation of BP after liquorice exposure was associated with increased extracellular fluid volume[8]

Summary

Introduction

The mineralocorticoid receptor (MR)[1] and the glucocorticoid receptor (GR)[2] play an important role in the regulation of blood pressure (BP) Both MR and GR are expressed in several tissues important to BP homeostasis, including the kidney, vascular wall, central nervous system, and the heart[2,3,4]. Cortisol binds to both GR and MR, aldosterone is the only physiologic agonist of the MR3. The balance of cardiac autonomic tone was evaluated by the use of power spectral analysis of heart rate variability (HRV)[16]

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