Licorice, the spice, is derived from the root of the licorice plant, a perennial in the legume family that can grow as tall as 7 feet. Licorice is 50 times sweeter than sugar and the active constituent of licorice root, known as gycyrrhizin, has been used in traditional herbal medicine systems for a variety of purported medicinal effects. Scientific research provides support and reveals information on the mechanism for some of the traditional uses of licorice, including those associated with its effects on hormones and the endocrine system. Due to potentially serious side effects, always use licorice under the supervision of a qualified health care provider.
Androgens
Licorice showed antiandrogenic properties -- properties that counteract male hormones -- in a study on laboratory animals published in the August 2009 issue of the "International Journal of Andrology." In the study, doses of 150 mg and 300 mg per kilogram of body weight daily for seven days, resulted in significant decreases in prostate size, reduction in tissues surrounding the prostate and decrease in total testosterone levels. The researchers concluded, from the results of this preliminary animal study, that licorice may act by increasing the breakdown of testosterone or by causing an inhibition of testosterone receptors or an activation of estrogen receptors. Further research is needed to discern the precise mechanism of licorice on androgenic hormones in humans.
Blood Pressure
Licorice exerts blood pressure-raising effects and raises blood pressure more in individuals with certain genetic variants, according to a study published in the September 2010 issue of the journal "Annals of Medicine." In the study, participants, all of whom previously showed a tendency toward licorice-induced hypertension, were found to have a variation in a gene that regulates sodium absorption by the kidneys. These individuals exhibited average blood pressures of 201/118 mmHg in response to licorice consumption, in the study, with 120/80 mmHg being the acceptable normal level and 140/90 mmHg or more considered hypertension. The genetic variants associated with the increased blood pressure response to licorice were 20 percent higher than in a random control group of blood donors.
Pregnancy
Eating licorice or taking licorice supplements while you are pregnant might affect your baby, according to a study published in the November 2010 issue of the journal "Psychoneuroendocrinology." Glyccyrrhyzin, the active compound in licorice, inhibits an enzyme that inactivates cortisol, thereby elevating cortisol levels. The study found that children of pregnant women who consumed more than 500 mg per week of licorice during their pregnancies had as much as 33 percent higher cortisol levels than children of mothers who consumed lower levels of licorice. The researchers concluded that prenatal high exposure to licorice programs the body's stress response system to be overactive.
Advisory
The University of Maryland Medical Center cautions that regular consumption of more than 20 g per day of licorice may raise levels of the hormone aldosterone -- a steroid hormone that regulates blood pressure -- resulting in potentially serious complications including headache, high blood pressure and stress on the heart. For people with existing blood pressure, kidney or heart problems, even 5 g per day has been known to cause complications. The University recommends doses of 250 mg to 500 mg up to three times per day of standardized licorice extract for no longer than one week at a time. Lower doses should not be taken for longer than four to six weeks. At all times, use licorice only under the care of a qualified health care practitioner, due to the potential for serious side effects.
References
- "International Journal of Andrology"; Antiandrogenic Activities of Glycyrrhiza Glabra in Male Rats. Zamansoltani F, et al.; August 2009
- "Biochimica et Biophysica acta"; The Role of 11?-Hydroxysteroid Dehydrogenase Type II in Human Hypertension. Ferrari P.; et al.; December 2000
- "Psychoneuroendocrinology"; Maternal Prenatal Licorice Consumption Alters Hypothalamic Pituitary Adrenocortical Axis Function in Children. Räikkönen K, et al.; November 2010
- "University of Maryland Medical Center": Licorice
- "University of Maryland Medical Center": Possible Interactions with:Licorice
- MedlinePlus.com: Hypertension
