Elevation
of Cortisol Levels by Ingesting
Liquorice
Simon B. N. Thompson, Dilara Sava
Department of Psychology,
Faculty of Science & Technology
Abstract
The effects of liquorice on the hormone
cortisol are known but are not well understood.
It has been noted anecdotally, but there remains
little scientific literature on the link between
the effects of liquorice on the body and the
fact that cortisol is consistently implicated.
This study demonstrates the link between
liquorice and cortisol and the role that
cortisol plays, together with yawning, in
regulating brain temperature which is often
compromised in certain neurological disorders
such as multiple sclerosis. 13 volunteers aged
between 21 and 28-year-old ingested liquorice as
well as completing the Hospital Anxiety and
Depression Scale, General Health Questionnaire,
and demographic and health details. Saliva
cortisol samples were collected before and after
ingesting liquorice. In all cases, cortisol
levels were significantly elevated after
ingesting liquorice.
Résumé
Les effets de l'ingestion de réglisse
sur le cortisol sont connus mais ne sont pas
bien compris. Des données anecdotiques,
mais peu de littérature scientifique, ont
évoqué un lien entre les effets
physques de la réglisse et son action sur
le cortisol. La présente étude
démontre un lien entre la réglisse
et le cortisol et le rôle que joue le
cortisol, associé au bâillement,
dans la régulation de la
température cérébrale
souvent altérée dans certains
troubles neurologiques comme la sclérose
en plaques.
13 volontaires âgés de 21
à 28 ans ont ingéré de la
réglisse après avoir rempli une
échelle d'anxiété et de
dépression, un questionnaire
général sur leur santé et
leurs données personnelles notamment de
santé. Des échantillons de
cortisol salivaire ont été
prélevés avant et après
l'ingestion de réglisse. Dans tous les
cas, les taux de cortisol étaient
significativement élevés
après ingestion de réglisse.
The hormone cortisol has been associated
with yawning and has been described in the
Thompson Cortisol Hypothesis[1,2] that
suggests links the rise in cortisol triggers
which in turn lowers brain temperature.
Threshold level rises of cortisol are proposed
to be part of a complex mechanism since brain
temperature can rise dramatically in people with
MS[3] possibly due to excessive fatigue
and irregular sleep patterns.[4]
Cortisol is thought to regulate brain
temperature within the
hypothalamus-pituitary-adrenal
(HPA)-axis,[5] which is a natural
feedback loop to protect our bodies,[6]
and cortisol may communicate directly with the
motor cortex[7] as evidenced in mice by
Hasan et al.[8] where sophisticated
cortisol-specific receptors were involved during
motor learning tasks.
Cortisol is implicated during stressful
events and might be modulated by contagious
yawning.[9] Curiously, the hormone is
thought to rise during ingestion of liquorice
because of the effects of the main ingredient,
glycyrrhizic acid[10] on the kidneys.
This may be because of inhibition of the enzyme
11_-hydroxysteroid dehydrogenase type 2 which
normally inactivates cortisol in the kidney.
Liquorice is likely to inhibit this enzyme and
so results in increases in cortisol levels.
Since the first description of side effects of
liquorice,[11] some researchers have
found that girls exposed to high maternal
liquorice consumption through mothers during
pregnancy had higher body mass index for age and
reported more advanced pubertal development as
compared with boys.[12] Støving
et al.[13] suggested that increased
sensitivity to glycyrrhizic acid may also arise
in anorexia nervosa which may cause severe
hypokalemia when combined with bizarre eating
habits. Anecdotally, it would seem that people
can overdose on liquorice
consumption[14] which can cause
rhabdomyolysis, the breakdown of skeletal muscle
causing the release of myoglobin into the
bloodstream.[15] Myoglobin is the
protein that stores oxygen in muscles; too much
myoglobin in the blood can lead to kidney
damage.
Ottenbacher and Blehm[16] found that
liquorice ingestion can lead to increased
hypertension and others have shown that there
may be many complications arising from liquorice
consumption[17] including preterm
labor,[18] and ocular
complications.[19,20] The link between
cortisol and yawning is now
established,[1,7] and it is interesting
to note that liquorice may now also play a role
in creating artificially induced levels of the
hormone for effects that might be used usefully
for diagnosis or treatment monitoring.
DISCUSSION
This study presents interesting findings in
respect of cortisol elevations. The level of
cortisol found in the first saliva samples was
lower than that found in the second sample after
participants had ingested liquorice.
Furthermore, a significant difference was found
between the levels of cortisol in the first
sample compared with the second sample after
liquorice ingestion. This concords with studies
that have suggested liquorice ingestion acts on
the receptors responsible for cortisol release
and causes elevation in blood.[10]
Despite reports of possible side effects of
liquorice ingestion in terms of its effects on
body organs and functionality, it appears that
it may be worthwhile investigating further this
natural plant for its potential properties in
affecting cortisol levels, especially in those
who are affected by low cortisol production or
an irregular release of the hormone, such as
Cushing's syndrome.[27]
The authors acknowledge that it is a small
sample study but also that it supports previous
findings that indicate liquorice may be a
natural product with potentially far-reaching
benefit.
