A herbal approach to digestive health
/Words - Catherine Rudenko
Introduction
The use of herbs and plant extracts to manage digestive ailments in other species is well documented. Whilst equine specific research is somewhat limited, some research is available and shows promising results. The principle common to traditional herbal medicines, whichever system is adopted, is that the patient is considered as a whole. This includes taking into account age, current level of vitality, emotional state or personality, along with environmental challenges.
The digestive system is considered of primary importance as digestive health influences other aspects of health within the body. That traditional view is one that is now upheld firmly in modern science, as we become increasingly aware of the influence of gut health on other body systems. Within the human food sector there now exists a multitude of supplements targeting gut function, changing the microbiome, and promoting various health benefits derived from such changes.
Plants present an opportunity to do more to manage digestive health for horses in training but supply and safety are significant challenges. Not all herbs are approved for use in racing as they contain substances that are banned in racing, for example ephedrine commonly found in Indian snakeroot, or synephrine that is often found in bitter orange cultivars. Just because a herb is available online and marketed for equine does not mean it is safe to use in racing. There is also the consideration of supply chain, as the global herbal market does not operate with the racing industry in mind. Whilst many herbs are themselves safe for use in racing by their action or composition, the supply chain may expose them to contamination with herbs or other materials containing banned substances. It is therefore essential only to use herbs and blends from companies operating under codes of practice, such as BETA NOPS who are assessing and managing the risk of contamination with naturally occurring prohibited substances (NOPS).
The information below discusses some of the plants most commonly used or better evidenced for their effects on aspects of digestive health. Research is other species unless specifically stating equine. The information below is designed to provide an introduction to herbs commonly used for digestive health, the majority of which are available through reputable brands.
Herbs noted for antiulcer or antacid effects
Turmeric (Curcuma longa)
Traditionally used for symptoms including inflammation, gastritis and gastric ulcer. In a study looking at the effect of curcuma longa extract the effects noted were reduced gastric acid secretion and protection against gastric mucosal lesions (1). Effect noted as from blocking of H2 histamine receptors.
Chamomile (Matricaria recutita)
One of the most widely studied herbs. Well known for its antioxidant and inflammatory properties. It has also been studied for its effects on management of diarrhoea and gastric ulcers (2). Effect likely from antioxidant properties.
Milk Thistle (Silybum marianum)
Milk thistle has been reported as having protective effects against ulceration through its positive effects on mucosa.
Fenugreek Seeds (Trigonella foenum-graceum)
Traditionally used for a variety of digestive disorders. Fenugreek seeds have been studied and compared with omeprazole for their protective effects against ulcers. In one study the soluble gel extract from fenugreek seeds was found to be as effective as omeprazole for experimentally induced ulcers (3).
Licorice (Glycyrrhiza glabra)
Well known for its antiulcer properties in humans and documented as an effective antacid. Research has shown that licorice used in donkeys with glandular ulcers induced by phenylbutazone was effective at reducing ulcer severity. Licorice was also effective at preventing associated phenylbutazone induced hypoglycaemia (4).
There are other herbs also with reported ulcer benefits mostly from a healing perspective including corydalis, gotu kola and bacopa.
Combinations
Herbs are most often prescribed in combination, as a cocktail of herbs will provide more than one mode of action, and will take into consideration other aspects of a state of disease.
Herbal combinations for ulcers within equine research is limited but some studies exist for marketed products. An Italian company has shown efficacy of a combination of minerals and herbs, namely fenugreek, licorice aloe vera and fleawort extract at reducing ulcer severity score of thoroughbreds in training (5).
Another commercial preparation trialled in humans based on bitter candytuft, melissa leaf matricaria flower, caraway fruit, peppermint leaf, angelica root, milk thistle, elan-dine herb and licorice root was proven effective at lowering gastric acidity and inhibiting serum gastrin levels (6).
Herbs noted for anti-inflammatory effects of digestive disorders
Although gastric ulcers are the most common concern for horses the remainder of the digestive tract is equally challenged by the training environment and needs for high energy feeds. Herbs are often used, and well documented, for the management of human digestive disorders. Whilst there is not always a direct equine equivalent the similarities in conditions makes a herbal approach an interesting consideration.
Boswellia (Boswellia serrata)
A potent anti-inflammatory herb with evidence for use in management of inflammatory bowel disease (IBD) and Chron’s disease. In both cases, research proves Boswellia as effective as medication in some studies.
Chamomile (Matricaria recuita)
A herb with multiple benefits, including carminative effects. Widely used for any inflammatory condition of the bowel and gastrointestinal spasms.
Demulcent Herbs
This group of herbs is used to lubricate and protect digestive tract membranes. Some herbs in this group are also in the anti-ulcerogenic group, highlighting that herbs are often carry multiple benefits across categories. Their primary mode of action comes from mucilaginous substances, namely polysaccharide gels, that protect mucosal surfaces by adhering to them. They may also act as prebiotics and influence intestinal flora.
Marshmallow (Althea officinalis)
Used in humans for the management of inflammation of gastric mucosa.
Slippery Elm (Ulmus fulva)
Used for inflammation and ulceration of the stomach and for cases of colitis.
Licorice (Glycyrrhiza glabra)
Licorice has a similar effect, although slightly different mode of action, through increasing mucus production and promoting mucosal blood flow.
Fenugreek (Trigonella foenum-graceum)
Used in the management of gastritis.
Antimicrobial Herbs
There are numerous herbs with antimicrobial effects. The mostly widely studied group for gastrointestinal infections are those containing the active component berberine. It has been found effective in treating diarrhoea caused by Escherichia coli, Shigella dysenteriae and Salmonella paratyphi B, amongst others. Berberine is found in plants such as goldenseal, Oregon grape root and coptis root.
Chamomile and thyme are also in this category although not of the berberine group. Chamomile oil is reported as having antifungal activity and activity against gram positive bacteria. Thyme oil has antifungal activities against a wide range of organisms.
Antiviral Herbs
Whilst there are several herbs considered as having antiviral properties, such as Echinacea, there is little information specifically for efficacy against gastrointestinal viruses. The exception being for tormentil root, which has been investigated for its effects against rotavirus diarrhoea in children. Research has shown an extract of tormentil root was effective in shortening the duration of rotaviral diarrhoea.
Considerations
There is a considerable amount of research and evidence around the efficacy of some herbs, along with increasing understanding of their modes of action. As is often the case, equine specific research is limited and research from other species must be relied on.
Herbs that are well researched, are worth considering alongside a well-balanced approach to nutrition. The main challenge is not finding evidence of efficacy, but finding a source that is most appropriate to racing. Although herbs and extracts are readily available online it is important to purchase through companies that are aware of the risks of naturally occurring prohibited substances and are managing this risk with a focus on racing, and not to use any supplement containing known banned substances.
References
Kim DC, Kim SH, Choi BH, Baek NI, Kim D, Kim MJ, Kim KT. Curcuma longa extract protects against gastric ulcers by blocking H2 histamine receptors. Biol Pharm Bull. 2005, Volume 28, Issue 12
Mohamed-Amine Jabri, Nadhem Aissani, Haifa Tounsi, Mohsen Sakly, Lamjed Marzouki, Hichem Sebai. Protective effect of chamomile (Matricaria recutita L.) decoction extract against alcohol-induced injury in rat gastric mucosa. Pathophysiology, 2017, Volume 24, Issue 1
R Suja Pandian, C.V Anuradha, P Viswanathan, Gastroprotective effect of fenugreek seeds (Trigonella foenum graecum) on experimental gastric ulcer in rats, Journal of Ethnopharmacology, 2002, Volume 81, Issue 3
Masoud Ahmadnejad, Ghader Jalilzadeh-Amin, Benjamin W Sykes. Prophylactic effects of Glycyrrhiza glabra root extract on phenylbutazone-induced Equine Glandular Gastric Disease (EGGD). Journal of Equine Veterinary Science, 2022, V olume118.
Stucchi,L. Enrica,Z. Alessia,S. Giovanni,S. Serena,C. Contura,B. Ferro,E. Ferrucci,F. Efficacy of the administration of a natural feed supplement in the management of equine gastric ulcer syndrome in 7 sport horses: a field trial. American Journal of Animal and Veterinary Sciences. 2017, Volume 12, Issue 3
M.T. Khayyal , M. Seif-El-Nasr , M.A. El-Ghazaly , S.N. Okpanyi , O. Kelber , D. Weiser. Mechanisms involved in the gastro-protective effect of STW5 (Iberogast) and its components against ulcers and rebound acidity. Phytomedicine. 2006, Volume 13, Issue 1