By Jess Hallas-Kilcoyne

The world of equine oral supplements can be intimidating for the average horse owner. With so many different products containing so many different ingredients intended to target so many different problems (and at so many different price points), how does one decide? First things first…

Does your horse really need an oral supplement?

“Everybody has their own opinion about supplements,” says Shelley Nyuli, co-owner of the Abbotsford, BC-based SciencePure Nutraceuticals Inc. with her husband, Cal. “Knowledge is the key to supplementing properly. Just like in a human athlete, you want to balance your horse’s intake with his output. Feeding supplements to your horse is probably more important if you’re active on your horse.”

Ralph Robinson, owner and founder of Herbs for Horses, based in Guelph, Ontario, seems to agree. “If it’s a backyard horse that you throw a saddle on every now and again, you might not need [supplements]. But these products can certainly enhance the athletic performance of the horse, can support the athletic endeavour.”

Many equine supplements have been formulated to target specific health or behavioural problems in horses – such as joint supplements for arthritis, digestive supplements for ulcers, calming supplements for anxiety and stress, etc. Many of these supplements are offered as an alternative to drugs whose use may be prohibited by cost or deleterious side effects. 

Where to start?

It is strongly advised that you always consult with your veterinarian before incorporating any supplement into your horse’s diet. A veterinarian is your best resource when it comes to deciding on a dietary supplement, and should be able to recommend specific products or ingredients, as well as provide any cautionary advice. 

A high performance horse is more likely to require dietary supplements to support his athletic endeavour than the typical backyard horse that is ridden lightly or not at all. Photo: Naismith Photography; Courtesy of Mixxio/Wikimedia Commons

Look for ingredients whose effective use and dosage for the treatment of a specific problem is documented in the scientific literature. Often, if there is no research to support an ingredient’s efficacy in horses, there will have been clinical studies demonstrating its beneficial use in humans.  

“Horses and humans have the same basic biochemistry and the same basic physiology,” explains Dr. Gordon Chang, President and Head of Research and Product Development at Omega Alpha Pharmaceuticals Inc. based in Toronto, Ontario. “Things that work in humans also tend to work in horses.”

Finally, you should note that several ingredients, even herbal or so-called natural ingredients, commonly found in equine supplements are listed as controlled or prohibited substances by the International Equestrian Federation (FEI), which bans, or at the very least greatly limits, their use in competition horses.

With this in mind, following is a description of a select number of ingredients commonly found in three popular types of equine supplements: joint supplements, digestive supplements, and calming supplements.  

JOINT SUPPLEMENTS

A joint is the junction between two bones. The joint is surrounded by a capsule whose walls consist of a tough outer layer of connective tissue and a thin inner layer of tissue called the synovial membrane, which secretes synovial fluid. Synovial fluid is a viscous liquid that fills the joint capsule, lubricating the joint and nourishing the articular cartilage that coats the ends of the bones, reducing friction and providing cushioning. 

Inflammation of the joint (arthritis) can be caused by a traumatic injury, degenerative disease, or chronic wear and tear. Joint inflammation results in loss of viscosity of the synovial fluid and damage to the articular cartilage, which has no blood supply and so is unable to heal or repair itself.

Healthy Synovial Joint

Oral joint supplements are typically fed for one of two reasons: to treat an existing problem or to prevent the occurrence of a problem in the future. The goals in the treatment of an existing problem are to reduce the pain and other symptoms associated with the disease (usually arthritis), and to slow or stop the progression of the disease.

“An anti-inflammatory will help control the inflammation (reducing the pain), and if you can control the inflammation, you can help stop damage to the tissues and the joint,” advises Dr. Chang.

There are a multitude of ingredients that are used in equine joint supplements for their anti-inflammatory properties and their effectiveness in promoting overall joint health. 

Common Ingredients

Boswellia: Boswellia, also known as Indian frankincense, is an extract derived from the resin of the Boswellia serrata tree, which is native to India. Clinical studies have demonstrated boswellia to be an effective anti-inflammatory treatment for osteoarthritis in humans. 

Chondroitin sulfate: Chondroitin sulfate plays a major role in the structure and function of joint cartilage. As well as possessing some anti-inflammatory properties, it is thought to benefit arthritic joints by stimulating production of lubricating synovial fluid and inhibiting certain enzymes that contribute to cartilage damage. Chondroitin sulfate has been proven to be most effective in joint supplements when paired with glucosamine. 

Curcumin: Curcumin is the active ingredient in turmeric, the spice responsible for Indian curry’s flavour and bright yellow colour. A study published in 2012 found that curcumin, which was already known to be a potent anti-inflammatory, provided very positive results in human patients with rheumatoid arthritis. “Curcumin as an herbal extract is highly concentrated,” says Nyuli. “The benefits are incredible.”

Curcumin, the active ingredient in turmeric, is being hailed as the latest “wonder” drug for joint disease on account of its potent anti-inflammatory properties. Photo: Sanjay Acharya/Wikimedia Commons

Devil’s claw: An extract derived from a native African plant, devil’s claw has been used to treat arthritis in humans for thousands of years. Studies suggest that devil’s claw may be as effective as some pain medications for relieving discomfort in arthritis patients. The use of devil’s claw in horses will result in a positive drug test and should be discontinued a minimum of two days prior to competition.

Glucosamine: Glucosamine, in the form of glucosamine sulfate or glucosamine hydrochloride, is the building block for connective tissues, including cartilage. “It helps rebuild cartilage and is needed to rebuild the joint,” says Dr. Chang. Glucosamine, particularly when used in combination with chondroitin sulfate, is the cornerstone of any joint supplement. It is also thought to produce some anti-inflammatory activity. To be effective, a daily dosage of 6000 to 10,000 mg of glucosamine is required; a horse in work will usually require the 10,000 mg dose. 

Hyaluronic acid (HA): A naturally occurring substance found in synovial fluid, HA ensures adequate lubrication to reduce friction between the bones, as well as shock absorption. Its use in joint supplements may help to protect the articular cartilage from the deleterious effects of inflammation, at the same time reducing the pain of arthritis. When the combination of glucosamine and chondroitin sulfate proves to be inadequate to manage the symptoms of a horse’s arthritis, the addition of HA at a daily dose of 20 to 100 mg is often beneficial. 

Methylsulfonylmethane (MSM): MSM is an organic source of sulfur, which is necessary to strengthen collagen, the main component of the body’s connective tissue. “Every cell membrane in the body needs sulfur for strength,” says Nyuli. “MSM is your cartilage builder, your connective tissue builder, your collagen builder.” MSM is also an anti-inflammatory and enhances the function of glucosamine. A study of horses with hock arthritis indicated that a minimum daily dosage of 20,000 mg was required for MSM to be effective. 

Mint: Plants in the mint family, especially spearmint, contain moderate levels of an organic chemical, called rosmarinic acid (Ros-A), that is known to have anti-inflammatory properties. Studies at the University of Guelph in Guelph, Ontario, conducted by Dr. Wendy Pearson, demonstrated a marked reduction in joint pain and inflammation for horses with arthritis when their feed was supplemented with a particular type of mint that was specifically bred to contain 20 times as much Ros-A as wild mint plants. 

Vitamin C (ascorbic acid): A water-soluble vitamin and antioxidant, Vitamin C is necessary for the synthesis of collagen, which is a major component of cartilage. It is also thought to improve the absorption of tryptophan and MSM. “It actually opens the pathway in the stomach lining for the glucosamine and MSM to be absorbed through the stomach wall instead of in the intestinal tract,” says Nyuli. “That’s good because they get into the bloodstream first and they’re not competing in the intestinal tract with any other nutrients.” However, be careful not to over-supplement with vitamin C as this can be harmful to your horse.

DIGESTIVE SUPPLEMENTS

“The way we feed horses is all wrong,” says Robinson. “The horse is basically a fibre-digesting machine on four legs, designed to trickle feed. In the wild, horses will spend 18 to 20 hours a day wandering across the prairie munching on grass. When they’re walking and munching and constantly eating fibre, their digestive system works beautifully.”

Robinson largely attributes the most common equine digestive problems – colic, gastric ulcers, and hindgut ulcers – to the growing tendency among horse owners to feed large, infrequent meals that are low on forage and high on grain. 

Gastric ulcers occur when the erosive factors (acidity) in the stomach outweigh the protective factors (mucus and bicarbonate). Photo: Samir/Wikimedia Commons

“The horse’s digestive system was never designed to handle grain,” he says. “You get a lot of energy from grain, but you also get a lot of side effects and problems.”

Take gastric ulcers, for example. Simply put, gastric ulcers are caused by an imbalance between the stomach’s erosive factors (namely the hydrochloric acid secreted by the stomach to aid digestion) and the protective factors (mucus and bicarbonate also secreted by the stomach). 

“With too much stress and too much grain feeding, one of the first things that disappears is the mucilage (protective mucus), and that allows the acid of the stomach to start burning and eroding the stomach,” says Robinson. 

Forage in the stomach acts as buffer against the erosive effect of the acid, which is continuously secreted, even when the horse is not eating. 

The benefits of feeding a diet high in forage are virtually innumerable, and include decreased probability of gastric ulcers, hindgut ulcers, and colic, and reduced stress, anxiety, and boredom.

“When we house horses, we tend to feed them two square meals a day, one in the morning and one at night,” explains Dr. Chang. “Unless you feed free choice hay, the rest of the time the stomach is empty but this acid is still continuously being produced. If you have a horse in competition, you’re adding stress on top of that. No wonder a lot of horses have ulcers.”

Reducing inflammation can ease the pain and speed the healing of gastric ulcers. However, Dr. Chang points out that “most of the common anti-inflammatories from the drug world (the NSAIDs) actually cause gastric ulcers. But some natural herbs tend to help with ulcers because of their anti-inflammatory effect.”

Other diseases of the equine gastrointestinal tract that are associated with a high-starch, low-fibre diet are hindgut ulcers and colic. Too much grain and too little forage upsets the delicate balance of bacterial micro-organisms in the horse’s hindgut that are essential to digestion of feed material and absorption of nutrients. In addition to increasing fibre content in the diet, prevention of colic and hindgut ulcers can be accomplished by supplements that either seek to restore balance to bacteria in the gut, or provide a bulking agent to assist the passage of material through the hindgut for overall digestive health. 

Common Ingredients

Chamomile: The extract derived from the flowers of the chamomile plant has been used as an herbal remedy for thousands of years. One of the major chemical compounds in chamomile is alpha-bisabolol, which is known for its anti-inflammatory properties. Additionally, bisabolol has also been shown to reduce the secretion of the digestive enzyme pepsin in the stomach, without altering the amount of stomach acid. For this reason, it has been recommended as a treatment for gastric diseases, such as ulcers, in humans. 

Digestive enzymes: Digestive enzymes help break down feed material into its nutritional components. There are many different enzymes, each of which is helpful in the digestion of different types of nutrients. Take the digestive enzymes lactase and sucrase, for example, which target sugars in the stomach.

“They start the breakdown process of sugars,” explains Nyuli. “That allows more sugars to be absorbed through the stomach as opposed to in the intestine.”

Licorice: One of the principal medicinal uses of licorice is as a demulcent, an agent that coats and soothes mucous membranes, relieving pain and reducing inflammation. These properties make it a potentially effective treatment for gastric ulcers. “Licorice root has been shown to help control ulcers in humans,” says Dr. Chang. “They did a study in humans comparing the effect of licorice extract to a common NSAID, and the licorice was just as effective.” The type of licorice that has been indicated for treatment of gastric ulcers is deglycyrrhizinated licorice (DGL). 

Prebiotics: Prebiotics are non-digestible carbohydrates that help the beneficial microbial populations (the “good” bacteria) in the hindgut grow and flourish. A healthy population of “good” bacteria in the gut can help minimize the incidence and growth of “bad” bacteria, which can cause colic and hindgut ulcers. Common prebiotics used in equine digestive supplements include yeast and psyllium. Prebiotics should not be confused with probiotics.

Probiotics: While prebiotics contribute to the growth of beneficial micro-organisms in the gut, probiotics are the live micro-organisms themselves. “A probiotic is active bacteria for the intestinal tract, specifically the caecum,” says Nyuli. “All the coarse hays the horse eats are broken down in the caecum – that’s where most of the fibre goes through. So the caecum needs extra bacteria to break that fibre down.” 

Psyllium: Derived from plants in the Plantago family, psyllium is used in the body as dietary fibre, which passes through the gastrointestinal tract without being absorbed. “It’s a bulking agent,” says Robinson. “When you feed it, it increases peristalsis [which is] the movement of digest through the gut.” This regulates bowel elimination, and can reduce constipation and mild diarrhea.

Other Ingredients Found in Digestive Supplements: “Slippery elm and marshmallow root have been known to help with ulceration by coating the damaged areas, allowing them to heal, and they stimulate the body to improve the healing process of the ulcers,” says Dr. Chang. “Ginger also works, and L-glutamine, which is an amino acid that has been shown to have an anti-inflammatory effect.”

Robinson adds that meadowsweet and lemon balm are also potent herbal anti-inflammatories. 

CALMING SUPPLEMENTS

As in humans, chronic stress and anxiety in horses can lead to a wide variety of health problems including gastric ulcers, suppression of the body’s immune system, and loss of condition. Additionally, stress and anxiety can contribute to the development of undesirable behaviours in horses, such as spooking, bolting, rearing, and pulling, and have been implicated as a causal factor in many equine stereotypies, including cribbing, wind-sucking, pacing, and pawing. Before rushing to the use of sedative drugs or calming supplements in an attempt to correct these behaviours, it is essential that the root cause of the horse’s stress be determined and addressed. 

Derived from the Matricaria recutita plant, chamomile is a common herbal remedy, well-known for its calming effect and its anti-inflammatory properties. Photo: Franz Eugen Köhler, Köhler's Medizinal-Pflanzen/Wikimedia Commons

“Be sure you know why your horse is misbehaving,” says Dr. Chang. “For example, sometimes horses are not cooperative because they have ulcers. If they’re in discomfort, they’re not going to want to cooperate as much. If you have a horse that’s misbehaving because of ulcer issues, you can give them things to calm them down but it’s not going to be that effective because the problem really is pain in the stomach. In cases like that, if you give them something to help with the ulcers, you might get a much better effect than giving them something for calming.”

After ruling out physical discomfort, the most common stress-inducing factors for horses include inadequate turnout, a diet that is low in fibre and high in starch, large and infrequent feedings, and limited interaction with other horses. Even addressing one of these factors can have an astonishingly beneficial (and sometimes measurable) effect on your horse’s mental and emotional health. Take diet as an example; according to a 2010 study, horses on a high fibre diet had significantly higher levels of serotonin than those on a high starch diet.

Serotonin is one of several neurotransmitters, including dopamine, norepinephrine, gamma aminobutyric acid (GABA), and melatonin, whose presence in sufficient amounts is associated with feelings of happiness, well-being, calmness, and relaxation. Their imbalance, on the other hand, is thought to be a potential cause of depression and anxiety disorders in humans, and many antidepressants and anxiolytics (anti-anxiety agents) target and attempt to modulate them. Many of the common ingredients in equine calming supplements are chosen for their ability to regulate these neurotransmitters to have a calming, mood enhancing effect in humans, the theory being that they will have a similar effect on horses. While more research is needed to verify this theory, many owners report dramatically positive results in their horses from the use of equine calming supplements. 

If you’re considering feeding a calming supplement to your horse, be aware that, according to the FEI: “The use of any herbal or natural product to affect the performance of a horse or pony in a calming (tranquilizing) or an energizing (stimulant) manner is expressly forbidden by FEI regulations.” While many ingredients in equine calming supplements will not result in a positive drug test, before feeding them to your show horse you should always confirm that their use is not contrary to competition rules. 

Common Ingredients

5-hydroxytryptophan (5-HTP): Derived from the seeds of Griffonia simplicifolia, a shrub native to West Africa, 5-HTP is an amino acid that functions as a metabolic intermediate in the biosynthesis of the neurotransmitters serotonin and melatonin from their chemical precursor, tryptophan. 5-HTP is a common over-the-counter dietary supplement used as an antidepressant and sleep aid. While there are no studies documenting the use of 5-HTP in horses, Robinson calls it “a good calmer.”

Chamomile: Although it also has anti-inflammatory properties, chamomile is best known for its use as a treatment for insomnia and anxiety in humans, with recent research suggesting it may have some value as a treatment for depression. Its ability to function as an anxiolytic and an antidepressant is thought to be the result of certain chemical compounds found in chamomile which modulate GABA and monoamine neurotransmitters. 

Inositol (vitamin B8): Inositol is an organic compound found in the body tissues of all animals. It is required for the formation of healthy cell membranes and helps regulate the transfer of electrical energy and nutrients across cell membranes. Studies suggest that inositol may be effective in treating depression, panic disorder, and obsessive-compulsive disorder in people by reversing the desensitization of serotonin receptors in the brain. 

Magnesium: A vital macromineral, magnesium plays a role in over 300 different chemical reactions in the body. Research demonstrates a correlation between magnesium deficiency and several mental health problems, including anxiety and depression, in people. Conversely, other human studies also suggest that magnesium supplementation may have an effect similar to that of antidepressants and anxiolytics. 

Taurine: An organic acid present in animal tissues, taurine contributes to the healthy function of the cardiovascular, musculoskeletal, and central nervous systems, among others. Animal studies have shown taurine to produce an anxiolytic effect, thought to be a result of its ability to regulate some neurotransmitters, including GABA and glycine. There is evidence demonstrating that the latter may be effective as a sleep aid in humans. 

Thiamine (vitamin B1): Thiamine is essential to the function of many cellular processes within the body, including the further breakdown of the building blocks of carbohydrates, fats, and proteins to release their energy. It also plays a role in the biosynthesis of certain neurotransmitters, including GABA, which might explain why thiamine deficiency has been linked to some anxiety disorders. Horses that are fed diets high in grain and those in heavy work are more likely to require thiamine supplementation. The standard dosage ranges from 500 to 1000 mg/day. 

Tryptophan: Tryptophan is an essential amino acid and a biological precursor for serotonin and melatonin, neurotransmitters associated with mental and emotional well-being. Animal studies indicate that tryptophan decreases aggression and may reduce stress; however, its effect on behaviour seems to vary according to age, breed, and gender, as well as diet and exercise, and more research is needed to determine the dosage at which it is most beneficial as an equine calmer. 

Valerian: Extract from the dried root of the valerian plant has been used for over 2000 years to relieve anxiety and insomnia. Animal studies have shown valerian to possess sedative properties, probably resulting from the influence of valerenic acid, one of the major constituents of valerian, on GABA levels in the brain. Valerenic acid is specifically designated a “Controlled Substance” on the FEI Equine Prohibited Substances List; however, Robinson recommends it as an excellent calmer for use in horses on stall rest to encourage them to stand quietly.

This article is provided for information purposes only and should not be relied upon as a substitute for professional veterinary advice. No liability will accrue to the publisher or author of the article in the event that a user suffers loss as a result of reliance upon this information.  

This article originally appeared in the August 2013 issue of Canadian Horse Journal. 

Main Photo: Canstock/Sonyae