“Hey doc, what is the best joint supplement for my horse?” The answer is different for every horse.
The purpose of using a joint supplement is to maintain or improve the health of your horse’s synovial joints. A synovial joint exists where two or more bones lined with articular cartilage meet. The space between the two articulating bones is called the joint cavity, which is filled with synovial fluid. The two primary functions of a synovial joint are to permit movement and transfer load between bones. In a normally functioning joint, both of these tasks are achieved in an efficient and pain-free manner. At the ends of the bones in a synovial joint exists a thin layer of articular cartilage. Cartilage is a padding that lines the ends of bones that form joints. Thus, every time your horse takes a step, the cartilage absorbs the pressure exerted on the knee joint. The parts of cartilage that have the ability to absorb this pressure are the fibers and proteoglycans. Proteoglycans are abundant, large, molecules of a variety of shapes and sizes and compositions. As with the fibers, they are also made by cells and then taken outside of the cells to form part of the gelatinous ground substance. The proteoglycans interact with the fibers, such as collagen, to help maintain the health and resiliency of connective tissue. The amount of proteoglycans within cartilage decreases with age, thus contributing to the development of arthritis.
Proteoglycans are complex molecules made up of a protein core with many long-chained sugar molecules linked to it. Cartilage, then, is made of countless of these proteoglycans in close proximity to fibers, such as collagen, and cells called chondrocytes. Some of the proteoglycans possess up to 100 glycosaminoglycan chains. There are at least six types of glycosaminoglycans including hyaluronate, chondroitin, dermatan, keratan, heparin, and heparan.
The long glycosaminoglycan chains are negatively charged and thus repel each other. When two molecules have the same electrical charge, they repel each other and if they have opposite charges, they attract. This characteristic of repelling allows proteoglycans to occupy a lot of space in connective tissue and cartilage. It also gives them the ability to be resilient, permitting compression and re-expansion. Cartilage can thus withstand the compressive load of weight bearing and then re-expand to its previous dimensions when that load is relieved. Proteoglycan synthesis is influenced by glucosamine supplementation and a variety of physical (exercise), biochemical (calcium levels, vitamins, hormone levels, and medicines) and mechanical effects.
Normal adult cartilage tissue does not contain any nerves or blood supply. The source of nutrients for cartilage comes from synovial fluid that bathes the surrounding joint. This fluid consists of some filtrates of blood plasma, proteoglycans and proteins from specific synovial cells. Synovial fluid has two important functions. First, it serves to lubricate cartilage as they slide over each other during movement. Second, it supplies the nutrients, and removes the waste products from the cells within cartilage. These cells, called chondrocytes, have no direct blood supply. Because cartilage tissue exchanges nutrients and waste by-products by passive diffusion, joint movement (i.e. physical activity) is essential for the maintenance of normal articular cartilage.
Trauma is not the only way joints get damaged. Normal use over time can lead to degeneration and breakdown. Running, jumping, pounding, carrying heavy loads, and normal daily movement all accelerate joint problems. Throughout life, articular cartilage undergoes internal remodeling as the cells replace matrix macromolecules lost through degradation. Aging decreases the ability of chondrocytes to maintain and restore articular cartilage and thereby increases the risk of degeneration of the articular cartilage surface. Progressive degeneration of articular cartilage leads to joint pain and dysfunction that is clinically identified as osteoarthritis. Degenerative changes cause the normally smooth cartilage to become rough due to a loss of chondrocytes (the cells that make cartilage, fluid and connective tissues for the joint). When this happens, they do not produce normal synovial fluid or connective tissue, and pain becomes a symptom.
REMEMBER THESE IMPORTANT POINTS:
- Nutritional support can help maintain and heal joint tissues.
- Ingredient quality is extremely important.
- Choose products formulated by professionals to address structural problems, not those designed to cover pain.
- Structural change through nutritional supplementation takes weeks, not days, to be seen.
- Always consult your veterinarian before using a joint supplement in combination with any other supplement or medication.
- Consult your veterinarian and show officials before using any supplement or medication in a performance horse.
- Be sure that you are providing nutrition, not drugs.
We don’t enjoy pain, and neither do our horses, but pain serves a very important purpose: it lets the rest of the body know that something is wrong. When a joint hurts, the natural response is for the other joints to do more work and let the painful joint rest. On their own, joints heal very slowly. If a damaged joint is not rested, it will get worse. The immune system supplies the injured joint with more blood than usual, feeding more nutrients so the joint can repair faster. Joint cartilage does not have blood flow, which is why movement of the joint is so important in the healing process.
If your horse is showing any signs of lameness or joint pain, it is always recommended to have your horse examined by a veterinarian so an accurate diagnosis can be made. Relying on a joint supplement instead of obtaining an accurate diagnosis may delay appropriate treatment for some conditions and result in permanent damage or longer recovery.
The ingredients most commonly added to joint supplements are there either to mask or cover symptoms (pain or inflammation) or to address the underlying problems that are causing the pain. Some ingredients can quiet pain very quickly and effectively but may not do much to help the underlying problem. For a body to use the building blocks provided through good nutrition to rebuild tissues, it usually takes 4-8 weeks for enough new fluid and tissue to be present for the pain to stop. Intra-articular (IA) injections of corticosteroids, hyaluronic acid, and polysulfated glycosaminoglycans are often used as aggressive therapy to decrease inflammation and swelling. IA injections should ALWAYS be done by your horse’s veterinarian. Oral supplementation should be used as an adjunct to IA injections and, if started with the first injection, will decrease the number of injections required by your horse.
Glucosamine is the predominant ingredient in joint products and is derived from “chitin,” which in turn is derived mainly from shrimp and crab shells. Glucosamine helps keep joints and cartilage lubricated, as well as stimulating the formation of glycosaminoglycans. This is important because as a horse’s body ages or is subjected to punishing riding disciplines, it may not produce a sufficient amount of glucosamine. This can result in cartilage that loses its ability to act as a shock absorber in the joints. The joints then become stiff and painful, resulting in a limited range of motion and even deformation.
Glucosamine provides the building blocks to synthesize new cartilage. Glucosamine also appears to have some mild anti-inflammatory effects. Studies have shown that when Glucosamine Sulphate is given orally, within 30 minutes, 87-97% is actively taken from the gut into the blood. When linked together with sulfur, chains of glucosamines become several different types of connective tissues and joint fluid. (A lack of sulfur will cause the production of connective tissues to stop.) Glucosamine is a precursor of hyaluronic acid, which in turn makes synovial fluid. A good starting dose will provide 6,000 to 10,000 milligrams (mg) glucosamine.
Chondroitin sulfate is a major constituent of cartilage, providing structure, holding water and nutrients, and allowing other molecules to move through cartilage—an important property, as there is no blood supply to cartilage. In degenerative joint disease, such as osteoarthritis, there is a loss of chondroitin sulfate as the cartilage erodes. Studies indicate that chondroitin sulfate may support healing of bone. It plays an important role by combating and neutralizing destructive enzymes in the joint. There is no question to the function of this ingredient when produced naturally in the body; there is significant research to show that when administered as a supplement, the rate of absorption results for chondroitin sulfate are less than favorable due to its molecular size (anywhere from 250 times the size of a glucosamine molecule). It does seem to improve the results when included with glucosamine. Remembering that as much as 70% may be excreted, a starting dose of 1,250 to 5,000 mg should help.
Hyaluronic acid (HA) is a mucopolysaccharide that occurs naturally throughout the horse’s body. One of hyaluronic acid’s most important functions in the body is to lubricate joints as an integral component of synovial fluid. There is a difference in hyaluronic acids of various molecular weights with studies showing that higher molecular weight acid gives better results. The higher molecular weight acid can hold more water, thus better lubrication properties. With joint injury, destructive enzymes break down the HA and the joint loses the cushioning effect of the synovial fluid. Sodium hyaluronate or HA may protect the joint by increasing the viscosity of the joint fluid, reducing inflammation and scavenging free radicals. HA has been found to increase the thickness of the joint fluid (therefore offering more cushion to the joint), to inhibit damaging enzymes, and to jump-start the body into manufacturing its own sodium hyaluronate. HA is particularly good for controlling pain, heat, and swelling. Generally, dosage is 100 mg/day.
Methylsulfonylmethane (MSM) contains sulfur in a form the horse’s body can readily use. Sulfur is necessary for the production of collagen, glucosamine, and chondroitin, which are the building blocks of cartilage. Sulfur is also necessary in the formation of glutathione, which functions as one of our body’s best natural antioxidants. MSM has been promoted as having anti-inflammatory and pain reducing properties. MSM supplements do not help with the cartilage or synovial fluid; they reduce the swelling that causes pain. Inflammation can place pressure on nerves and other tissues which intensifies pain. MSM promotes blood flow, which enhances the healing processes. It may take as much as 20,000 mg per day to make a difference.
Avocado and soy unsaponifiables (ASUs) are plant fats that are normally protected from digestion and absorption in the intestinal tract but are extracted and purified by a special procedure. In an equine study where arthritis was induced by a surgical procedure, these substances showed a protective effect against cartilage breakdown in a group of supplemented horses compared to those not supplemented. However, they did not appear to have an effect on pain. ASUs are classified as a “chondroprotective” if given to horses at a rate of at least 1,200 mg/day.
A variety of anti-inflammatory herbs are often added to equine joint supplements, but “it’s in there” is no guarantee the amount is enough to have any effect. These herbs are most useful for horses who continue to have pain despite adequate doses of other joint nutraceuticals.
Devil’s Claw contains several chemicals that are reported to decrease pain. It does not decrease inflammation and is similar in structure to steroids. A product should contain 2,500 mg of a standardized 0.25% harpagoside extract to be effective.
Yucca contains steroid saponins, chemicals related to steroids. In the animal’s body, steroid saponins decrease pain and inflammation. Steroids also decrease the immune response, and have been shown to slow the production of glycosaminoglycans. Dosage will vary according to the percentage of the saponin powder and should be around 300 mg of saponin after the math is done (3,000 mg of a 10% product).
Boswellia, White Willow’s Bark, and Snake Root are herbs that contain chemicals that act as NSAIDs – non-steroidal anti-inflammatory drugs. These drugs decrease pain and inflammation and are known to cause severe gastrointestinal (GI) problems such as ulcers when given in excess and for too long. Boswellia will need to be given at a rate of 500 mg/day of extract to get the effects.
Bromelain is an enzyme found in pineapples. It has been shown to reduce the amount of swelling present in some experimental animals. There can be problems with reactions to bromelain.
If you are using a supplement including one of the above you may decide to rotate it with a milder supplement to help avoid problems.
In traditional medicine, immediate masking of pain is accomplished through the use of drugs that are placed in the body either orally or by injection. These drugs (including herbal ingredients, which are plant drugs) change the way the body normally functions so that pain is not recognized and/or the immune system stops the inflammatory response (and slows the healing process). The main types of drugs used are steroids (such as Cortisone or Prednisone), and NSAIDs (such as Banamine, Phenylbutazone, Ibuprofen, Ketofen, or Aspirin), drugs that alter the recognition of pain or interfere with the immune response.
Dr. Bill Ormston operates Jubilee Animal Health, a mobile, mixed animal practice in the Dallas Metroplex area, using mostly alternative methods. Dr. Ormston is one of the founding instructors of the post-graduate course in Animal Chiropractic at Parker Chiropractic College in Dallas. He has lectured nationally and internationally on Animal Chiropractic and biomechanics, and gait analysis in the quadruped.