Out-of-office blood pressure is more strongly associated with cardiovascular risk than office blood pressure. Licorice is known to raise blood pressure, but no previous studies have measured the effects on home blood pressure. The aim of this study is to analyze the association between licorice intake and home blood pressure.
Healthy volunteers will be invited to participate in a randomized, non-blinded, cross-over study. Participants will be randomized to either of two groups with a 1:1 allocation ratio, stratified by sex. Intervention will be sweet licorice and control will be salty licorice. A run-in period of 1 week will be followed by a 2-week intervention/control, a 2-week washout period, another 2-week control/intervention period and again a 2-week washout period. Home blood pressure will be measured continuously, and blood samples (including potassium and aldosterone) will be collected every two weeks. Analyses will be made comparing baseline characteristics of the two groups, intervention/control and washout period results of the two groups to look for potential carry-over effects, and finally comparing intervention and washout period results respectively to the baseline data to look for the effects of licorice.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
28
Ecologic, vegan and gluten free, low-sodium sweet licorice pastilles made from Glycyrrhiza glabra, with a manufacturer specified content of 4% sugars, 2% glycyrrhizin and 0.03% salt, will be used as intervention. The exact glycyrrhizin content will be determined before the study begins, and participants will be instructed to consume a daily licorice dose that is equivalent to 100 mg of glycyrrhizin.
A vegan and gluten free salty licorice without glycyrrhizin, flavored with ammonium chloride, with a manufacturer specified content of 0% sugars and 0.05% salt, will be used as control. The amount of salty licorice will be the same as for sweet licorice, and thus determined after the glycyrrhizin content analysis of the sweet licorice.
Cityhälsan Centrum
Norrköping, Östergötland County, Sweden
Systolic home blood pressure (mmHg)
Systolic home blood pressure (mmHg)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
Diastolic home blood pressure (mmHg)
Diastolic home blood pressure (mmHg)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
Body weight (kg)
Body weight (kg)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
Plasma potassium (mmol/L)
Plasma potassium (mmol/L)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
Plasma sodium (mmol/L)
Plasma sodium (mmol/L)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
Plasma renin (mIU/L)
Plasma renin (mIU/L)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
Serum aldosterone (μmol/L)
Serum aldosterone (μmol/L)
Time frame: Mean at the end of 14 days of intervention compared with mean during run-in period
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