Joints—there is always plenty to say about them, and for good reason. Healthy joints and their durability are essential when considering the wellbeing of any animal. One of the most common reasons for veterinary visits is lameness, and the majority of lameness cases are related to joint inflammation and the resulting joint damage, meaning osteoarthritis.
Bones and joints continue to develop throughout a dog's entire adult life. Load placed on a joint is not always a bad thing: it is known that a certain degree of load is necessary for strength, power, and endurance to increase. The body needs strain in order to become stronger. For that reason, a dog's amount of exercise should also be increased gradually. Problems can arise if the amount and intensity of exercise are increased too much at once, or if the dog does not receive sufficient nutrients from the diet to maintain joint health. The biggest risk factors include aging, excess weight, injuries to the joint, and overload due to physical work. The role of hereditary factors is also significant.
CROSS-SECTION OF A JOINT
Let's go through a bit of joint anatomy so that we can understand what is inside a joint and what happens when injuries occur.
Joints connect two or more bones and allow them to move in relation to each other. The joint is held together by a joint capsule, and the thin inner lining of this capsule is called the synovial membrane. The synovial membrane secretes synovial fluid, which lubricates the joints. Synovial fluid enables movement without the bones rubbing directly against each other, and in this way it helps prevent wear of the joint surfaces.
The structures described above are surrounded by the joint capsule and supported by ligaments. The ends of the bones are covered by a smooth layer of articular cartilage, which consists of specialized cartilage cells that produce abundant extracellular matrix. Cartilage is a crucial component of the musculoskeletal system, because it is what allows the high pressures placed on bone ends to be cushioned. In a healthy joint, those pressures do not cause cartilage wear. Cartilage is also the part of the joint most prone to damage. Problems arise when joints are exposed continuously to greater-than-natural strain. In such a situation, the animal's own defense system cannot produce enough nutrient compounds that are essential for joint healing, and that allow the joint to remain healthy. In that case, cartilage degeneration triggers a chain reaction that leads to joint inflammation, stiffness, lameness, and pain. Over the long term, inflammation in the joint leads to osteoarthritis, so responding to inflammation early is essential for maintaining joint function. Osteoarthritis is a degenerative joint disease characterized by progressive destruction of normal articular cartilage and the underlying bone. Even though the root cause of osteoarthritis is not known and there is no curative treatment, symptoms can be significantly alleviated.
TREATING JOINT DISEASES – NUTRITION CAN HELP
Most commonly, a veterinarian treats osteoarthritis and joint inflammation with intra-articular injections, most often corticosteroids. Support can also be gained from different orally administered complementary feeds. These can be used both to try to prevent problems and to ease an existing issue, while supporting the joint's ability to function. The health of articular cartilage is an essential factor for a dog's mobility and wellbeing, so it is worth taking a closer look at it. How, then, could joint health be taken into account in a dog's diet?
Especially for young animals, it is essential that they receive adequate nutrients from the diet in the correct proportions so that they grow and develop into healthy, durable individuals. However, nutrition is important throughout the dog's entire life cycle. It becomes especially important again as the dog ages or as the level of exertion increases.
There are nutrients that can support and promote the formation of synovial fluid. There are also nutrients that help maintain normal joint function and mobility and can reduce changes occurring in bones.
The most important nutrients affecting joint protection are glucosamine and chondroitin sulfate, both of which are also found naturally in the body.
GLUCOSAMINE, CHONDROITIN SULFATE, HYALURONAN, AND MSM
Glucosamine is a substance naturally present in articular cartilage, and its amount decreases in osteoarthritis or with age. Glucosamine acts as a joint "lubricant" that supports joint health, functional capacity, and mobility. The role of glucosamine is to keep synovial fluid thick and elastic and to prevent it from becoming thin and watery. Glucosamine is also one of the key compounds needed for the formation of other factors involved in joint protection. It participates in regulating cartilage growth and repair. Glucosamine exists naturally in the body, but when the need for glucosamine increases, it has been observed that the body can also utilize glucosamine available in the bloodstream (i.e., obtained orally). Adding glucosamine to the diet—both as prevention and to support rehabilitation of potential existing joint injuries—is therefore recommended for dogs whose joints are under heavier-than-normal load or who have, for example, a hereditary predisposition to joint problems. Glucosamine should be used long-term, for three to six months, in order to see whether it benefits the individual dog.
Chondroitin sulfate is an important nutrient for the normal health of cartilage. In addition, studies suggest that it may have the ability to reduce inflammation and thereby inhibit the activity of enzymes that degrade cartilage. It also stimulates cartilage renewal.
In osteoarthritis, the amount of chondroitin sulfate in cartilage tissue decreases already in the early stages of degeneration. Chondroitin sulfate cannot cure osteoarthritis, but it may relieve symptoms and may even slow the progression of osteoarthritis while supporting cartilage-building processes. Chondroitin sulfate increases the production of hyaluronan in the joints, which in turn increases the viscosity of synovial fluid.
Hyaluronan, or hyaluronic acid, is found in the spaces between cells almost everywhere in the body, and it is an important building block of cartilage. Hyaluronan is needed especially in tissues that grow, renew, and heal quickly. Hyaluronic acid functions as a cushioning, elasticity-maintaining substance as well as a lubricant in joints and other tissues. In addition, it may influence how the body responds to tissue damage.
MSM is an organic sulfur compound that occurs naturally in the body. Sulfur is an essential component in many different compounds and functions in the body. Sulfur supports the flexibility and permeability of cell membranes, thereby promoting freer transport of nutrients and waste products. Sulfur also provides the body with raw material as it creates new cells and repairs and renews damaged tissues. Sulfur is also needed for the formation of connective tissues and collagen. MSM is known above all as a nutrient that supports building connective tissues such as joints, bones, and nails. Sulfur is also found in rosehip seeds.
The ingredients listed above are among the most common and most researched components affecting joint wellbeing. Of course, there are many others as well, and you can find information about them on our site under the "joints" section.
When adding joint-supporting compounds to the diet, it is important to remember that they work best over time. You should not expect "magic tricks" within a few days. However, this does not mean the dog must receive them for the rest of its life. It is simply more effective to give small amounts regularly than, for example, to add them only right before heavier exertion.
