Glucosamine is a naturally occurring amino monosaccharide, which is present in the connective and cartilage tissues and contributes to maintaining the strength, flexibility and elasticity of these tissues. It has been widely used to treat osteoarthritis in humans and, over the past few decades, in pets.
Glucosamine for dogs can be extremely effective in the treatment of arthritis symptoms. Glucosamine and chondroitin have both been utilized in the treatment of skin injuries, stomach ailments and skin problems and their biggest usage now is in the upkeep and relief of osteoarthritis.
Several short- and long-term clinical trials in osteoarthritis have shown the significant symptom-modifying effect of glucosamine. According to the recent biochemical and pharmacological studies, administration of glucosamine normalizes cartilage metabolism, so as to stimulate the synthesis and inhibit the degradation of proteoglycans and to restore the articular function.
In addition to its chondroprotective action, glucosamine exerts anti-inflammatory actions by inhibiting neutrophil functions such as superoxide generation, phago- cytosis, granule enzyme release and chemotaxis. Moreover, glucosamine is demonstrated to prolong the allogeneic cardiac allograft survival by suppressing the activation of T-lymphoblasts and dendritic cells.
More recently, glucosamine has been reported to suppress the growth of parasite (Plasmodium falciparum) by interfering with glycosylphosphatidylinositol biosynthesis.
Platelets have a critical role in normal hemostasis, whereas they also contribute to thrombotic disorders such as myocardial infarction and peripheral vascular diseases.
A recent study by scientists at the Department of Host Defense and Biochemical Research, at Juntendo University in Japan, found that platelet aggregation was suppressed after oral administration of glucosamine and the scientists discovered that glucosamine possesses an antithrombotic activity to suppress platelet functions.
Furthermore, long-term clinical trials with oral administration of glucosamine for 3 years have shown no apparent side effects for treatment of osteoarthritis. Therefore, glucosamine is also used now as a novel and safe anti-platelet agent for thrombotic disorders.
Glucosamine Usage in Dogs
Dietary supplements such as glucosamine and chondroitin sulfate are widely used to relieve the symptoms from osteoarthritis in both humans and animals, particularly dogs and cats.
What is Glucosamine?
Glucosamine is a naturally occurring aminomonosaccharide derived from chitin in crustacean shells. It is a combination of glucose and the amino acid glutamine.
Glucosamine is a major component of proteoglycans and is vital for the synthesis of glucosaminoglycans (components that hold water in the supporting structure of cartilage) and collagen.
Glucosamine Absorption in Dogs
A study by Adebowale et al of the bioavailability and phamokinetics of glucosamine in dogs found that the absorptions of glucosamine HCl occurred 1.1 to 1.6 hours after oral administration. The bioavailability after a single dose was 12.1 – 12.7% and after multiple dosing was 9.7 – 10.6% (dosage was 1500 – 2000mg).
It is interesting to note that in this study, chondroitin sulfate absorption occurred 1.54 – 2.7 hours after administration and had a bioavailability of 4.8 – 50% (dosage of 1200 – 1600mg).
However after multiple doses, the bioavailability was 200 – 278! The animals tested were all beagles of an average weight of 12 kgs.
Glucosamine Effectiveness in Dogs
A study by Canapp et al of the effects of two orally administered glucosamine products on chemically induced synovitis in the radiocarpal joint of dogs found that the dogs previously treated with glucosamine for 21 days had a protective effect against chemically induced synovitis and associated bone remodeling. Prior treatment with glucosamine had also reduced lameness in dogs with induced synovitis, as compared to a placebo control group.
A separate study, by Johnson et al, investigated the effectiveness of glucosamine / chondroitin sulfate in dogs with surgically transected cruciate ligaments on the histological reaction within the stifle joint.
Histological markers (3B3 and 7D4) that indicate synthysis and turn over of the matrix of proteoglycans and collagen by chondrocytes were utilized. Johnson studied four groups:
- A sham treatment group (receiving a sham arthrotomy) and given glucosamine.
- A group that had the transection, received glucosamine and then a sham repair after 4 weeks.
- A group that had the transection, no glucosamine and then a repair at 4 weeks.
- A group that had the transaction, received glucosamine and then a repair at 4 weeks.
Johnson found that at the one-month stage following transection, there was no difference between the treatment. At the three month stage, the glucosamine groups showed elevated levels of the 3B3 and 7D4 markers as compared to the non-glucosamine group.
This included the treatment group that did not have the repair of the transected cruciate! The study reported that glucosamine / chondroitin sulfate alters proteogycan biosynthesis as well as anti-inflammatory, anticatabolic and chondroprotective actions.
Over-Dosage or Side-Effects of Glucosamine
Anderson et al reviewed articles on glucosamine and found that there was no evidence of toxicity with large doses in animals. Dosages as high as 5,000 – 15,000 mg/kg were reported. Additionally, oral doses of 159 – 2700 mg/kg/day for 12 – 365 days had no noted adverse side effects.
Further Information on the Uses of Glucosamine and Chondroitin
Glucosamine products have been studied and used for the healing of skin wounds, some stomach ailments, as well as joint problems. Currently, their biggest use is in the relief of the symptoms of joint disease. Glucosamine and chondroitin have been successfully used in humans, horses, dogs, and cats.
Many different joints can be affected by osteoarthritis; but the most common joint affected in the dog is the hip. Hip dysplasia is very common in many of the larger breeds of dogs.
This condition greatly exacerbates the normal wear on the smooth cartilage protecting the bony surface of the joint. When this cartilage wears away, there is bone-to-bone contact, which creates the pain seen with dog arthritis.
Even dogs which do not have hip dysplasia may have a decrease in this cartilage as they age, and will show signs of arthritis. Furthermore, aging dogs may also have arthritis in their knees, elbows, or shoulders, with cartilage loss or damage that often responds to glucosamine and chondroitin therapy.
Glucosamine and chondroitin supplements may also be used post operatively in dogs which have undergone joint surgery.
The typical canine patient that is placed on and responds to glucosamine and chondroitin therapy is a middle aged to older, medium to large breed dog. Most older dogs suffer from some level of osteoarthritis.
Dogs may show symptoms of limping or stiffness, particularly in the morning and during cold weather, but typically loosen up as they move around and exercise. Some dogs have difficulty climbing stairs or getting into or out of a vehicle.
Dog owners may attribute the loss of activity to old age and may not even identify it as a problem. Sometimes they don’t realize how much their dog’s activity level has been limited by arthritis until they start their dog on a glucosamine and chondroitin supplement and see the improvement.
Osteoarthritis can also affect cats and small breed dogs and glucosamine and chondroitin have been used very effectively in relieving their symptoms, also.
Where are glucosamine and chondroitin found?
Glucosamine and chondroitin are natural substances found in the body of living animals. They are at their highest concentration in cartilage. Through degradation during digestion and processing, almost all of the glucosamine in an animal’s diet is unavailable for use. The body, therefore, synthesizes most of its own glucosamine through a biochemical reaction utilizing glucose.
In normal, healthy animals, the body is capable of synthesizing sufficient quantities of glucosamine to keep the existing cartilage healthy, however when the animal ages or there is damage to joint cartilage, it cannot produce enough to keep up with the body’s needs. This is when your dog needs a supplemental form of glucosamine, such as that in Nutrition Strength’s Hip and Joint Health Support Supplement for Dogs and Cats.
Supplemental glucosamine: Glucosamine is obtained from chitin — an ingredient found in the shell of crustaceans. Crustacean shells have a very high concentration of chitin and because the shells are often discarded, this provides a reliable and cost effective source of glucosamine.
Chondroitin: Chondroitin is a naturally occurring product found in animal cartilage. Supplemental chondroitin is derived primarily from bovine (cattle) cartilage, especially the cartilage rings of the trachea. It is also derived from shark and whale cartilage. The source does not appear to have any impact on its effect.
How do glucosamine and chondroitin work?
Glucosamine provides patients with the building blocks to synthesize new cartilage.
The way that glucosamine works is a very complicated process. In a nutshell, cartilage consists of several different cells, one of which is chondrocytes. Chondrocytes are responsible for synthesizing new cartilage. Through normal wear, cartilage is constantly being broken down and replaced.
When a dog has hip dysplasia or ages, the chondrocytes do not have the building blocks available to them to build enough new cartilage to keep up with the breakdown of the old cartilage. Glucosamine provides the building blocks needed to synthesize new cartilage.
Glucosamine is the building block necessary for the production of the substances called glycosaminoglycans. The glycosaminoglycans are combined with hyaluronic acid to make the substance proteoglycans. The proteoglycans and collagen are the main structures of cartilage.
Chondroitin blocks destructive enzymes that break down cartilage in the joint. Chondroitin is also one of the products necessary for the synthesis of glycosaminoglycans.
However, chondroitin likely plays a more important role by combating and neutralizing destructive enzymes in the joint. There is always a low level of destructive enzymes found in the joint, however when injury or abnormal wear occurs, the destructive enzymes and agents increase, accelerating cartilage destruction. When chondroitin is added to the diet it helps to reduce the level of these destructive enzymes.
Supplements with Chondroitin and Glucosamine for Dogs
Products that contain human-grade glucosamine and chondroitin, such as Nutrition Strength’s Hip and Joint Health Support Supplement for Dogs and Cats, are much more likely to be of high quality and in a purer form.
Apart from the ingredients, the concentration of actual glucosamine and chondroitin vary from product to product. Canine products may be flavored or fortified with other minerals. The most expensive product is not necessarily the best.
You should always compare the ingredients in products to ensure that you are getting what you pay for. Some of the most popular products for canines include those supplements found in Nutrition Strength’s product line.
These products are not painkillers, but they work by actually healing the damage that has been done. They generally take at least six weeks to start to heal the cartilage and most animals need to be maintained on these products the rest of their lives to prevent further cartilage breakdown.
As these products are naturally occurring compounds, they are very safe and have been shown to have no side effects.
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