Horsemen's Journal, March 1991
Reprinted with permission


by William E. Jones, D.V.M.

Horsemen and Veterinarians have begun supplementing horses' diets with mucopolysaccharides for nutritional therapy and as a preventive aid

The old adage, "You are what you eat," is not literally true, of course. But as more is learned about nutrition, we realize that it can produce wonderful changes in health. Unless you are a biochemist, you probably have not heard about mucopolysaccharides. Yet these awkwardly named, unsung nutrients make up a major part of the horse's body, as well as our own. Mucopolysaccharides, more easily referred to as MPs, are made in many varieties, but they all have similar chemical building blocks. It now appears that they may be especially helpful to the equine athlete.

According to Dr. Bruce W Halstead, medical director of the Halstead Preventive Medical Clinic, MPs are as important in nutrition as amino acids, essential fatty acids, vitamins, and minerals. The MPs react with the "bricks" of connective tissue, collagen and elastin, to maintain the normal function and structural integrity of the joints, arteries, heart, brain, skin, and other tissues. They form cross-linkages with proteins such as collagen, the basis of cartilage. In short, they act as the internal structure of tissue, holding all cells together - thus maintaining the elastic gel nature of connective tissue.

Surprisingly, these building blocks are not as easy for the body to make from basic food substances as was once thought by nutritionists. The distribution pattern of MPs changes with maturation and aging. Researchers think that the process of aging is directly connected to altered MP metabolism. Pinch and rub the arm of an 80 year-old person and then the arm of a 20-year-old person and you will feel the difference MPs make to the connective tissue under the skin.

Several companies produce and/or sell some form of nutritional MPs for horses. A common source is freeze-dried bovine trachea which, processed with various enzymes, yields MPs called chondroitin sulfates. Another source of MPs is the green-lipped mussel (Perna Canaliculus), which is harvested near New Zealand. This edible shellfish is reputed to contain a high concentration of MPs, and other nutrients.

Studies have shown that MPs exert potent anti-inflammatory action on connective tissue diseases and have a powerful capacity to regulate immune response. The MPs act in part by coating cellular membranes, which can help limit inflammation. This, in turn, allows an increase in the viscosity, or lubrication capacity, of joint fluid. This means an MP supplement can be helpful in preventing, and even treating, joint problems in the racehorse.

According to Halstead, the broadest therapeutic application of MPs in human medicine is in cardiovascular therapy. The MPs are responsible for the elasticity of the blood vessels.

Rich proportions are found in the walls of the arteries. MPs are important to the process of structural repair and the control of inflammation. These qualities, along with their capacity to limit coagulation inside the blood vessels, all play potential roles in the prevention of cardiovascular disease.

These actions are also beneficial to the racehorse. Chondroitin sulfates in MPs give negative charges to blood platelets and cells. This limits their tendency to clump and stick together, thus preventing clot formation within arteries. This is a physiological response much needed by the racehorse when the spleen has dumped its contents of red blood cells into the general circulation. The blood becomes extremely thick, and the clumping of blood cells which often occurs can cause problems.

There are many other known uses of MPs, according to Halstead. They include the improved movement of white blood cells, reduced susceptibility to "foreign substance shock" (anaphylaxis), growth stimulating effects including reversal of cortisone inhibition of growth, increased sodium excretion, and increased resistance to viral and bacterial infections. These are all effects which are quite beneficial to the horse at the racetrack.

Veterinarians are using MPs as a feed supplement for joint problems in horses. Dr. Bill Mitchell in Oklahoma sees quite a few joint problems in his work on performance horses. In some cases, he prescribes an MP feed supplement and has observed tremendous change in some horses. With others, he has not seen the benefit until after the horse is taken off the supplement. Mitchell kept records on 35 cases of arthritis in which he prescribed MPs. He started them all out with the feed supplement and asked the owners to follow up, giving the supplement as long as it seemed to be helpful. Twenty percent of the horses were still on the supplement a year later.

One of the first researchers to explore the clinical effects of MPs was Dr. John E Prudden. About 25 years ago, he began experimenting with a remarkable wound-healing substance made with a special preparation of cartilage rings of cow trachea. The finished product was called Catrix. Prudden and his colleagues conducted a most convincing controlled study of the healing capacity of Catrix, using two exactly corresponding incisions which were made on opposite sides of a subject's body and deepened to the muscle level. One of the paired incisions was treated with topical Catrix powder and one was not. Otherwise, the incisions were closed in an identical manner. Later, the incisions were removed and the tissue was taken to the laboratory for analysis of tensile strength. The result was that the Catrix treated incisions were 42% stronger.

Prudden later published a book in which he described how he discovered that Catrix was effective in treating osteoarthritis when given orally. He had been treating two types of digestive tract inflammation by injecting large amounts of Catrix under the skin. In a flash of scientific insight, he realized that he could treat the diseases "topically" by giving Catrix to his patients orally. In this way, he could bring the MPs into direct contact with the diseased intestinal tract.

This new approach, chosen specifically for intestinal inflammation, opened more doors. "Many of these patients also suffered from osteoarthritis," Prudden wrote. "When their arthritis began to improve, I realized that the drug might be effective by the oral route, a feature I had not expected with so complex a biological mixture. Subsequent clinical observation and laboratory tests have led me to believe that it is almost as effective when administered orally as when injected under the skin." Prudden went on to do extensive research with the use of Catrix in the treatment of arthritis. He prescribes a freeze-dried bovine trachea product called "Mucopolysaccharide Concentrate."

One of Halstead's colleagues, Dr. Lester M. Morrison, explored the absorption, distribution, metabolism, and excretion of MPs administered to animals and patients in his book Coronary Heart Disease and the Mucopolysaccharides (Glycosaminoglycans). Morrison pointed out that it is important to know whether the MPs actually get to the cells which show improvement, and if they do, whether complete MPs, or just their fragments, enter the cells. And if the MPs enter the cells, Morrison asked, what form do they take inside the cells?

Morrison knew that conventional medical theory would question whether the relatively large MP molecules would be able to enter the cells, even when injected. "These questions become even more critical when it is considered that acid mucopolysaccharides such as the chondroitin sulfates appear to yield results when administered orally." They worked, but how?

Given the success of oral administration, Morrison expected to find MPs in significant amounts in the circulating blood and in urine following ingestion, And since it was known that the cells could excrete MPs, he suspected that they could also take them in.

He went on to find evidence that MPs such as chondroitin sulfates and their derivatives could be absorbed through the intestines. Studies of patients at the University of Tokyo School of Medicine showed that at least two types of chondroitin sulfates could be absorbed. One was a natural form chondroitin-4-sulfate which was traced by a radioactive "tag." The other was an altered, "polysulfated" form of chondroitin-6-sulfate which was traced directly. The tracing of "tagged" chondroitin-4-sulfate showed that about 40% was absorbed within the first 24 hours. Surprisingly, large size molecules were found in blood and in urine, and were shown to have been absorbed through the intestine.

After citing the findings of a whole series of studies, Morrison concludes that a proportion of chondroitin sulfates given orally to animals and human subjects is absorbed in intact form, without major chemical changes. The studies indicated that the degree of depletion of the MPs in the tissues could affect the amount of uptake. In other words, cells needing MPs may take up more than those which are well stocked.

There have been many laboratory animal studies of MP absorption which show that this form of nutritional therapy can be effective in man (and horses). A considerable amount of empirical, practical evidence, along with data from solid research, makes it quite probable that oral administration of mucopolysaccharides can result in intact uptake and use in tissues that need them.

In conclusion, mucopolysaccharide supplementation may be beneficial to the horse in several ways. Those horses in greatest need, or in a state of deficiency, tend to receive more benefit from supplementation. Osteoarthritis (more commonly referred to as degenerative joint disease in the horse) is helped through MP supplementation. The healing of strains and sprains, which often plague equine athletes, is improved with MP supplementation. Repaired tissue is stronger because of MP supplementation. Various forms of intestinal inflammation (enteritis), which are common in horses at the racetrack, are helped during the healing phase with MP supplementation.

We still do not know exactly how oral MPs work to help the horse, but human trials, lab animal studies, and practical evidence provide enough proof to many horsemen and veterinarians that they are using mucopolysaccharides as nutritional therapy and a preventive aid.

Dr. William E. Jones has been authoring Veterinary Update for Horsemen's Journal since 1980 and has been writing on various aspects of equine medicine for the past 15 years.