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The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis

Abstract

There have been numerous case reports of severe adverse events including deaths following chronic licorice ingestion. The aim of the present study was to evaluate the effect of chronic ingestion of licorice on blood pressure, plasma potassium, plasma renin activity and plasma aldosterone. A search of MEDLINE, PubMed, EMBASE, CENTRAL, DARE, CINAHL and Current Contents Connect was performed from inception through to 26 April 2017. Trials that included a treatment group ingesting a product containing at least 100 mg of glycyrrhizic acid daily were selected. Pooled mean changes from baseline with 95% confidence intervals were calculated for diastolic blood pressure, systolic blood pressure, plasma potassium, plasma renin activity and plasma aldosterone using a random effects model. An assessment of dose–response was also undertaken. A total of 18 studies (n=337) were included in the meta-analysis. There was a statistically significant increase in mean systolic blood pressure (5.45 mm Hg, 95% CI 3.51–7.39) and diastolic blood pressure (3.19 mm Hg, 95% CI 0.10–6.29) after chronic ingestion of a product containing glycyrrhizic acid. Plasma potassium (−0.33 mmol l−1, 95% CI −0.42 to 0.23), plasma renin activity (−0.82 ngml−1 per hour, 95% CI −1.27 to −0.37) and plasma aldosterone (−173.24 pmol l−1, 95% CI −231.65 to −114.83) were all significantly decreased. A significant correlation was noted between daily dose of glycyrrhizic acid and systolic blood pressure (r2=0.55) and diastolic blood pressure (r2=0.65), but not for the other outcome measures. Hence, chronic licorice ingestion is associated with an increase in blood pressure and a drop in plasma potassium, even at modest doses. This is of particular relevance for individuals with existing cardiovascular disease.

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Acknowledgements

We would like to acknowledge the generous Summer Research Scholarship provided by the University of Sydney that funded the costs of retrieving the medical records for this study.

Author contributions

Study concept and design: EME and GDE. Acquisition of data: RP. Analysis and interpretation of data: GDE and RP. Drafting of the manuscript: RP. Critical revision of the manuscript for important intellectual content: GDE. Statistical analysis: GDE. Study supervision: GDE.

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Correspondence to G D Eslick.

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Penninkilampi, R., Eslick, E. & Eslick, G. The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis. J Hum Hypertens 31, 699–707 (2017). https://doi.org/10.1038/jhh.2017.45

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