Volume 22, Issue 1, February 2014, Pages 81–86
Herbalists’ perception of risks involving commonly sold medicinal plants in Italy
Summary
Objective
Although
there are several studies which have investigated pharmacists’
knowledge of the safety of medicinal plants (MPs), no studies have
examined herbalists’ perception of risks associated with MPs.
Methods
We
conducted a survey of 159 herbalists (participation rate 85.9%) in the
region of Tuscany (Italy). Data were collected by means of a
semi-structured questionnaire using a face-to-face interview. Risk
perception was rated on a 10 cm Visual Analogic Scale (VAS). Herbalists’
scores were then compared with those reported by a group of 10 experts
in herbal medicine.
Results
When
the overall risk was examined, herbalists had a low perception of the
risks (VAS median ranged between 1.5 and 3.2) associated with the use of
most MPs (Allium sativum, Aloe vera gel, Echinacea spp., Escholtzia californica, Harpagophytum procumbens, and propolis). They had an intermediate or high perception of risks associated with use of Cimicifuga racemosa, Citrus aurantium, and Panax ginseng
(median ranged between 3.5 and 5.0), and for anthraquinone laxatives
(median 7.2). Although the overall risk perceived by experts was
generally higher than that reported by herbalists, differences were
statistically significant only for Allium sativum and Escholtzia californica.
Conclusion
The
study shows that herbalists in Tuscany are knowledgeable about the
relative risks of MPs when compared with experts in herbal medicine.
Keywords
- Herbalists;
- Medicinal plants;
- Risk perception;
- Survey;
- VAS
Introduction
The use of medicinal plants (MPs) is increasing in most Western countries 1, 2 and 3, including Italy [4]. “Natural” remedies are generally considered safe by users mainly because they are “natural” [5].
However, their consumption may lead to adverse reactions and/or
undesired clinically significant interactions when taken in concomitance
with pharmacological treatments 6 and 7 or when used by subjects with certain clinical conditions 8, 9 and 10.
While
several studies have evaluated the knowledge of pharmacists and other
public health providers about the safety of MPs, and found that these
generally have poor understanding of the risks 11, 12, 13 and 14, we have found no studies investigating herbalists’ perception of the risks associated with certain MPs.
To
address this issue, we carried out a survey among a sample of
herbalists in Tuscany about the most commonly sold MPs. A group of
experts in the field of herbal medicine was used as a reference to
compare the herbalists’ scores.
Methods
The
survey was conducted from January to June, 2010, in herbalist's shops
in the provinces of Florence, Pistoia and Prato, (region of Tuscany,
Italy), and involved 159 herbalists (participation rate equal to 85.9%)
of 80 shops (covering 80% of herbalist's shops of the two provinces, and
20% of all herbalist shops in Tuscany). All eligible participants
received written and oral information about the aim of the study.
Data
were collected by means of a semi-structured questionnaire (Appendix)
administered by a trained herbalist using a face-to-face interview. Risk
perception was rated by means of a 10 cm Visual Analogic Scale (VAS).
That is, subjects were asked to rate on the VAS from 0 (very low risk)
to 10 cm (very high risk) how they perceived the global risk related to
the use of 10 MPs (Allium sativum, Aloe vera gel, anthraquinone laxatives, Cimicifuga racemosa, Citrus aurantium, Echinacea spp., Escholtzia californica, Harpagophytum procumbent, Panax ginseng,
propolis) and the risk of specific adverse effects (i.e., intestinal
disturbances, hepatic damage, gastritis, cardiac damage, drowsiness,
neurological damage and allergy) related to the use of each herb. The
study was limited to the above 10 MPs because they are the most commonly
sold in Italy. The questionnaire also collected socio-demographic
characteristics (age, gender, education and occupation) of participants.
The
questionnaire was tested and validated by an ad hoc panel of experts
(pharmacologists, epidemiologists, toxicologists, pharmacists and
clinicians) of the Tuscan Regional Center of Pharmacovigilance, and a
clinician of the regional referring Center of Natural Medicine.
A
group of 10 experts in herbal medicine, comprising pharmacologists,
toxicologists, pharmacists and clinicians, was used as the gold standard
group and these individuals were asked to complete the same
questionnaire administered to the herbalists.
Values
were presented as medians and interquartile ranges. In order to compare
medians between the two groups (herbalists versus experts) the Median
test was used. A p-value of <0.05 was considered
statistically significant. Further analysis was conducted by stratifying
herbalists according to their educational level and years of work in an
herbalist shop.
We
indicated the risk was a “low risk” if VAS values ranged between 0 and
3.3, “intermediate risk” if values ranged between 3.4 and 6.6, and “high
risk” if values ranged between 6.7 and 10.
Results
Eighty-two
percent (139 subjects out of 159) of interviewed herbalists were
female, 42% (67 subjects) had a university degree, and 59% (94 subjects)
had at least 10 years of work experience in an herbalist shop.
Table 1
shows medians and interquartile ranges of overall risk perception
(using the Visual Analogic Scale related to the use of 10 medicinal
plants) among the 159 herbalists and 10 experts. Herbalists had a low
perception (medians ranged between 1.5 and 3.2) of the global risks
associated with the use of most MPs under study (A. sativum, A. vera gel, Echinacea spp., E. californica, H. procumbens, and propolis), an intermediate one of C. racemosa, C. aurantium, and P. ginseng (medians ranged between 3.5 and 5.0), and a high perception for anthraquinone laxatives (median = 7.2). Experts graded A. vera gel (median = 1.6) and Echinacea
spp. (median = 2.9) as low risk, and all other MPs (medians ranged
between 3.4 and 5.6) as of intermediate risk. The global risks reported
by the experts were generally higher than those perceived by herbalists
with the exception of anthraquinone laxatives. However, the differences
were statistically significant only for A. sativum (p-value = 0.048) and E. californica (p-value = 0.048).
- Table 1. Medians and interquartile ranges of global risk perception (using the Visual Analogic Scale) associated with the use of 10 medicinal plants as perceived by 159 herbalists and 10 experts in the natural products area.
Medicinal plants Median (Interquartile range) p-Value a Allium sativum Herbalists 2.1 (0.9–4.0) 0.048 Experts 4.6 (2.5–5.9) Aloe vera gel Herbalists 1.5 (0.5–3.4) 0.985 Experts 1.6 (0.5–6.1) Anthraquinone laxatives Herbalists 7.2 (5.0–8.1) 0.192 Experts 5.3 (4.2–7.3) Cimicifuga racemosa Herbalists 3.5 (2.1–5.4) 0.514 Experts 4.1 (3.0–4.8) Citrus aurantium Herbalists 4.0 (1.7–5.8) 0.172 Experts 5.6 (4.1–8.9) Echinacea spp. Herbalists 2.0 (0.0–8.4) 0.408 Experts 2.9 (1.8–3.9) Escholtzia californica Herbalists 2.5 (1.0–4.1) 0.016 Experts 3.6 (3.0–6.8) Harpagophytum Herbalists 3.2 (1.2–4.7) 0.954 Experts 3.4 (3.0–4.8) Panax ginseng Herbalists 5.0 (3.7–6.8) 0.832 Experts 5.1 (3.2–7.0) Propolis Herbalists 2.6 (1.1–4.5) 0.150 Experts 3.4 (2.6–7.4) -
- a
- Median test.
The herbalists correctly identified the risks related to certain MPs in relation to specific disorders (Fig. 1).
In fact, all identified risks were in agreement with those reported by
the experts (all differences in the medians reported by herbalists and
by experts were not statistically significant).
- Figure 1.
Medians of risk perception of selected disturbances (using the Visual Analogic Scale) carried by the use of 10 MPs among 159 herbalists and 10 experts in the natural products area.
When
results were stratified according to the herbalists’ educational level
(university degree or lower degree) and work experience (≥10 and <10
years), no substantial differences were found. However, the perception
of risk appeared higher among herbalists with a university degree when
compared with those with a lower degree, as well as among those with
less than 10 years of work experience when compared with those with 10
years or more of experience (data not shown).
Finally,
more than half of the herbalists (54%) reported to have observed
adverse reactions associated with the use of MPs. The herbal remedies
and adverse reactions most frequently observed were: anthraquinone
laxatives because of intestinal disturbances or gastritis, P. ginseng and Paulina cupana because of nervous system and cardiovascular disorders, Matricaria recutita, Echinacea spp., and propolis because of allergic reactions, and Hypericum perforatum because of photosensitivity reactions affecting the skin.
Discussion
This
is the first survey investigating herbalists’ perception of risks
associated with the use of medicinal plants. Our findings show that
herbalists in Tuscany are knowledgeable about the safety profile of MPs.
The quantified estimates of their risk perception, overall or related
to specific adverse effects, are similar to those of a group of experts
in herbal medicine and pharmacovigilance.
Several
studies have evaluated of the knowledge of pharmacists and other public
health providers about the safety of MPs, and shown that their
understanding is rather poor 11, 12, 13 and 14.
A systematic review investigating United States and Canadian
pharmacists’ attitudes about knowledge of and professional practice
toward herbal or alternative therapies showed that approximately equal
numbers of pharmacists report positive as well as negative attitudes
about the safety and efficacy of these remedies, although it was not
possible to draw a definitive conclusion due to the heterogeneity of the
data [11].
This review clearly shows that there is a need for pharmacists to
receive additional training in the field. A study from the USA
interviewing 111 physicians, 30 advanced practice nurses, 46
pharmacists, and 350 dietitians, found that participants had key
deficits in knowledge about the adverse effects of herbs and dietary
supplements [12].
Another Australian study of 80 pharmacists showed that less than
one-third of responders believed that “most complementary and
alternative medicines are safe and have very few side effects”, and
one-fifth neither agreed or disagreed with the same statement [13].
In Europe, an Italian survey investigating the attitudes and knowledge
of 1420 consumers and pharmacists regarding the safety of natural
products, concluded that pharmacists are more likely to answer correctly
about the use of herbs rather than about caution, adverse effects and
interactions [14].
In our survey A. sativum is considered safe by herbalists, and relatively safe by experts. Herbalists underestimated the risk of gastritis and allergy 15 and 16,
as highlighted by experts, or the risk of cardiac damage (i.e.,
alteration of platelet function and coagulation, with a possible risk of
bleeding) [15]. A. vera
gel is perceived as safe. Side effects are rare, and only a case of
hypersensitivity (contact dermatitis or slight itching after
application) has been reported to date [17].
Anthraquinone
laxatives are considered relatively safe by herbalists but as high risk
by experts, with possibility of unfavorable effects on the intestine or
provoking gastritis. Plants containing anthraquinones can induce
diarrhea, abdominal pains or mucus in the feces [18], thus worsening constipation or irritable bowel syndrome [19].
C. racemosa
is considered relatively safe. Herbalists, as well as experts, did not
emphasize that it can give slight and transitory collateral effects such
as headache, gastric problems and skin rash [20], or have unfavorable effects on the circulatory system or hepatitis [21].
C. aurantium is perceived as relatively safe. Herbalists did not indicate possible cardiac damage, as emphasized by the experts. C. aurantium is obtained from the pith of the unripe fruit containing synephrine, a substance that could be toxic for cardiomyocytes 22, 23 and 24. Instead the outer layer (the rind) of the mature fruit is safe. Herbalists suggested that C. aurantium has unfavorable neurological effects, although such beliefs are not supported by the scientific literature.
Echinacea spp. is perceived as safe, even if allergic episodes, contact and anaphylaxis dermatitis have been reported [25]. However, there is a one out of 100,000 possibility that serious unfavorable effects associated with the use of Echinacea spp. can occur [21].
E. californica
is perceived as safe by herbalists, and relatively safe by experts.
Herbalists, as well as experts, indicated that drowsiness is a possible
unfavorable reaction [26]. In some cases, prolonged use or high doses of E. californica can cause addiction phenomena [27].
H. procumbens is perceived as safe by herbalists and relatively safe by experts who indicated gastritis as a possible adverse reaction [28]. Moreover, H. procumbens can cause cramping and nausea [28].
P. ginseng
is considered relatively safe, with possible cardiac effects and
neurological damage, as reported by experts and in the scientific
literature 29, 30, 31, 32, 33 and 34.
Finally, propolis is considered safe by herbalists and relatively safe by experts. They highlighted that it can cause allergies [35]. Propolis can give possible hypersensitivity reactions such as asthma [36], edema, respiratory and cutaneous disorders [37], and can be not tolerated at the gastrointestinal level [19].
The
characteristics of this present study mean that it is not possible to
compare our findings with those of previous ones. First, we quantified
the perception of risk and no other investigation has done this.
Secondly, the present study was specifically focused on herbalists,
professionals who are responsible for advising consumers on the use of
medicinal plants but whose education and training are completely
different from those of pharmacists.
Finally,
in our survey half of the herbalists we surveyed reported having
observed adverse reactions. Considering that from April 2002 to June
2010 only about 500 reports were recorded in the National Phytovigilance
System of the Italian National Institute of Health, it appears that the
majority of adverse reactions observed were not reported by herbalists.
Several
limitations affect the present study. Our sample size was small.
However, our survey involved 80 shops (and 150 herbalists) amounting to
80% of all the herbalist shops in the most populous provinces of Tuscany
(Florence, Pistoia and Prato), so our sample may be considered to be a
faithful representation of Tuscany herbalists. Our results may not be
generalized to herbalists at a national level or to all healthcare
professionals, being just from Tuscany. Finally, the questionnaire
relied on self-reporting information, thus, our results may under- or
over-estimate the real perception of risk associated with the use of MPs
on the part of herbalists.
Conflict of interest statement
None declared.
Funding
This work was supported by a grant from the Italian Ministry of Health (“Progetto Giovani Ricercatori” 2007) and from the “Fondazione Cassa di Risparmio di Pistoia e Pescia” (Prot. n. 2008.0286).
Acknowledgements
The authors thank Dr. Francesca Mannini and Dr. Angelica Traina for questionnaire administration, data collection and recording.
References
Copyright © 2013 Elsevier Ltd. All rights reserved.
