The laxative senna (Cassia senna L.) is widely used in food supplements also available in the form of common supermarket herbal teas. However, this plant can harmintestine and is among the laxatives placed under surveillance by the European Commission, for suspected damage to health. We asked the Istituto Superiore di Sanità (ISS) for clarification.
Senna, a 'natural' laxative with large numbers
In addition to being present in some Medicines available without a prescription (eg Pursennid, Novartis), senna – leaves and flowers of Cassia senna L. – is the main ingredient of many Dietary Supplements. From the best known, such as 'Fuca beans''Kelemata herbal tea', to many less famous brands and blends like '10, 20, 100 herbs' that promise 'relief, balance and lightness'.
The Seine it even appears in herbal teas for sale in supermarkets, registered as supplements, such as Sweet dreams Star regularity, Bonomelli Regularity, Kilocal, etc.
Such a large availability to expose large sections of the population to the risk of harmful effects on health. Often in the absence of adequate warnings on dietary supplement labels. With the wishful thinking that the productnatural' is always free of contraindications,.
Suspects for a decade
Security suspects in the consumption of senna and other derivatives of hydroxyanthracene as a laxative (chemical substances present in many botanical species) have already emerged in two scientific opinions of EFSA, in the last decade.
The first opinion dates back to 2013. When asked about the scientific substantiation of a health claim relating to hydroxyanthracene derivatives and the improvement of intestinal functions, theAuthority had confirmed these properties.
He had some thoughuse and prolonged consumption at high doses are not recommended due to potential safety issues such as the danger of electrolyte imbalance, a deterioration of intestinal function and addiction to laxatives'.
Under surveillance for 4 years
The second opinion of EFSA (2017) on hydroxyanthracene derivatives used as laxatives led to the ban on the use of some parts of aloe, which were found to be carcinogenic and mutagenic, without however obtaining sufficient evidence to ban senna. (1)
However, doubts remain. Since 2021 the seine is in fact under special supervision, for four years, together with other hydroxyanthracene derivatives (chemical substances present in many botanical species with laxative action).
Switzerland – where health policy rigorously follows the precautionary principle – in the meantime it already has forbidden the use of the laxative senna in supplements. (2)
An inappropriate use of senna for a prolonged period can also lead to an increase in intestinal laziness and a further worsening of constipation.
In case of chronic overdose may occur liver damage.
In the absence of a prescription, medicines containing senna preparations should not be taken for longer than 2 settimane and should not be used in children under 12 years of age or during pregnancy and breastfeeding.
Senna-based preparations cannot be taken even in case of inflammatory diseases of the gastrointestinal system, intestinal obstructions, kidney disease, dehydration and known hypersensitivity to one or more ingredients.
(Swiss Institute for Therapeutic Products)
In Italy and other countries however, the use of the substance is also widespread in supermarket shelf products, often without warnings to consumers. An anomalous circumstance, on which we asked the Istituto Superiore di Sanità for explanations.
The answers of the National Institute of Health (ISS)
The researchers Ilaria Ippoliti and Francesca Menniti-Ippolito of the National Center for Research and Preclinical and Clinical Evaluation of Medicines of ISS, which we consulted, essentially confirm that the laxative senna is used inappropriately by consumers.
1 – What is the evidence of harmfulness of Senna for the functionality of the intestine (doses and duration of consumption)?
'The Seine (Cassia senna L. or Cassia angustifolia) is a plant which contains, among other molecules, the so-called anthraquinone laxatives (called sennosides) which give the effect of a laxative with a very intense action, so much so that they are defined as "drastic laxatives of contact” and therefore their use is not recommended for prolonged periods of time.
In the monograph of the EMA (European Medicine Agency), for example, the use of senna preparations must last a maximum of one week. (3)
If the preparations are taken correctly and adequately (not for prolonged periods and only after having already tried other remedies such as a healthy and balanced diet, physical activity or milder laxatives) they are not harmful or toxic.
On the other hand, if they are taken incorrectly (even frequently) or for prolonged use, more or less serious adverse reactions may arise, which could lead, for example, to a effect on the intestinal epithelium and electrolyte imbalances with absorption defects.
In this regard, not many clinical studies on humans are available, however there is preclinical evidence, taken into consideration in the EMA monograph itself'.
Two ISS studies
'Over the past two years we have carried out two studies concerning respectively a systematic review/meta-analysis of literature studies to evaluate the risk of colorectal cancer and an analysis of the reports of adverse reactions to identify any health risks.
In both cases the data available did not make it possible to highlight particular safety problems or warning signs however have been encountered several cases of prolonged or inappropriate use of products containing senna; this must therefore be taken into consideration for the evaluation of the benefit/risk ratio for the health of the users'. (4)
2 – Which countries allow the use of senna only in medicines (but not also in supplements), as Switzerland already allows?
'Each country in the EU decides autonomously whether to authorize a substance or preparation as a medicine and this happens following a national authorization procedure, so to know if in a country are senna-based herbal medicines authorized reference should be made to the legislation in force in each Member State of European Union.
Food supplements from a legislative point of view are identified as food and follow, like several other product categories, the Regulation (EU) 2019/515 which establishes and regulates the free movement of goods.
In general the ban on marketing goods lawfully marketed in another Member State is one of the most restrictive measures that can be adopted and is carried out only in the event that other less restrictive measures (e.g. labelling) have not achieved effective results in protecting the public interest. In such cases the state carries out the full scientific assessment of the real risk to the population'. (5)
3 – Senna has been under observation since 2021, based on EFSA forecast. What exactly does 'under observation' mean?
'On November 22, 2017 EFSA has produced a scientific opinion on the evaluation of the safety of hydroxyanthracene derivatives (aloe-emodin, emodin and dantron) for use in food. Such derivatives were those present in various anthraquinone-containing plants including the leaves or fruits of Cassia senna L.
From these insights, EFSA has found that hydroxyanthracene derivatives, have shown to be genotoxic in vitro. Therefore it concluded that these molecules should be considered genotoxic and carcinogenic unless there were specific data showing otherwise.
He also specified that too plant extracts containing hydroxyanthracene derivatives there were concerns about safety, however there were still some uncertainties.
EFSA was unable to provide guidance on a daily dose of hydroxyanthracene derivatives that would not raise concerns for human health and concluded that the substances considered in the opinion should be banned'.
Senna noted special
'Following these conclusions the European Commission has applied the provisions of Regulation (EC) no. 1925/2006. Therefore the 'Regulation (EU) 2021/468 of the Commission of 18 March 2021 was issued which amends Annex III of regulation (EC) n. 1925/2006 of the European Parliament and of the Council as regards botanical species containing hydroxyanthracene derivatives.
Consequently the substances aloe-emodin, emodin, dantrone and aloe preparations containing hydroxyanthracene derivatives have been included in Part A of Annex III to Regulation (EC) No 1925/2006 and therefore are currently as "prohibited substances" in foods and therefore in food supplements.
As regards the plants considered, including Cassia senna L., the European Commission established that there is still no scientific certainty that these plants (or their preparations) contain the substances listed above (derivatives of hydroxyanthracene) therefore they must be subjected to European Union surveillance. Consequently, these are currently included in Annex III, part C, of Regulation (EC) no. 1925/2006.
In this case, according to the same regulation, food business operators, or any other interested party, may submit to EFSA, for its evaluation, a dossier containing the scientific data demonstrating the safety of these substances used in a food or category of food and explaining the purpose of that use.
Within four years from the date a substance was listed in Annex III Part C, the European Commission will take a decision taking into account the opinion of EFSA on any submitted dossiers.
From that decision the following may be established: the use of the substance without restrictions, the use of the substance but with particular restrictions, or the prohibition of use of the substance'.
Marta Strinati
Footnotes
(1) Panel on Food Additives and Nutrient Sources added to Food (ANS). Safety of hydroxyanthracene derivatives for use in food. EFSA. 23.1.18. DOI 10.2903/j.efsa.2018.5090
(2) Information about prohibited products such as herbal teas or capsules containing senna. SwissMedic. 7.1.22 https://www.swissmedic.ch/swissmedic/it/medicrime/news/warnings/publikation-senna.html
(3) European Union herbal monograph on Senna alexandrina Mill. (Cassia senna L.; Cassia angustifolia Vahl), folium EMA/HMPC/625849/2015
(4) Adverse events related to herbal dietary supplements and over-the-counter medications containing laxatives: a 10-year update from the Italian Phytovigilance and Pharmacovigilance systems. Lombardi N, et al. Ann Ist Super Sanita. 2022;58(2):131-138. doi:10.4415/ANN_22_02_09;
Niccolo Lombardi, et al. Anthraquinone laxatives use and colorectal cancer: A systematic review and meta-analysis of observational studies. Phytotherapy Research... 17 January 2022 https://doi.org/10.1002/ptr.7373.
(5) Application of the Mutual Recognition Regulation to Food Supplements - Training material for authorities - Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs 2020.
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
