Glucosamine: Supplement for Osteoarthritis

Glucosamine is a naturally occurring amino sugar. In human body, it is an important component of the cartilage of the joints and is produced by the conversion of glucose and glutamine with the help of the enzyme glucosamine syntheses. Besides cartilage, it is also required for the formation of skin, bones, eyes, hair and body tissues. It can be found as a component in chitosan and chitin, which form the exoskeleton of arthropods and crustaceans and the cell wall of fungi. So, the exoskeleton of these organisms is an important source for commercial production of glucosamine. It can also be produced by the fermentation of corn or wheat.

The first production of glucosamine was undertaken by Dr. Georg Ledderhose in the year 1876. He prepared it by the hydrolysis of chitin with hydrochloric acid. It is naturally made as glucosamine-6-phosphate, which acts as the precursor of all sugars that contain nitrogen.

In the human body, the main function of glucosamine is to act as the precursor in the production of glycosaminoglycans, which is an important constituent of the cartilage of joints. The cartilage act as a cushion and lubricating material and thus provides protection to the joints against damage. However, body's natural ability to produce glucosamine reduces with growing age due to shortage of the enzyme glucosamine syntheses.

Glucosamine, generally glucosamine sulfate, is mainly used in the treatment of osteoarthritis, a group of diseases generally caused by the damage or loss of cartilage. In osteoarthritis, the cartilage of joints loses elasticity and becomes stiff, which in turn causes pain, inflammation, tenderness, creaking and locking of joints.

As glucosamine is a precursor of glycosaminoglycans, therefore it is thought to be helpful in rebuilding cartilage of the joints, and hence is widely available as a nutritional supplement. It is generally combined with chondroitin sulfate, a compound found to be effective in improving elasticity and preventing destruction of cartilage. Chondroitin is also supposed to increase the efficacy of glucosamine. Sometimes, glucosamine can also be found along with methylsulfonylmethane (MSM) in nutritional supplements. Its efficacy is also believed to increase if taken along with vitamin C, magnesium and bromelain.

However, lots of controversies exist regarding the effectiveness of glucosamine in the treatment of osteoarthritis, especially knee osteoarthritis. Some studies have shown it to have substantial effects, not only in reducing the pain and stiffness associated with knee osteoarthritis, but also in slowing down the development of the disease. An important study was carried out by the National Institute of Health to find out the efficacy of glucosamine (glucosamine hydrochloride) and chondroitin among a group of knee osteoarthritis patients. Both glucosamine and chondroitin, alone or combined, have not been found to be very effective in reducing knee pain among the group of patients. However, in the above study, glucosamine hydrochloride was used instead of the generally used glucosamine sulfate.

Short-term use of glucosamine has not been found to cause any severe side effects. However sometimes, drowsiness, insomnia and digestive problems like pain in the abdomen, constipation, heartburn, diarrhea and vomiting can be experienced. Besides, people allergic to shellfish are also advised to avoid glucosamine as it is made from them. However, the allergens, responsible for producing allergic reactions are actually found in the flesh of the shellfish and not in the shells.

Glucosamine is also not prescribed to people who have bleeding disorders and are taking anti-clotting or anti-platelet medicines. Taking glucosamine is supposed to increase the risk of bleeding in case of these people. Besides, glucosamine is also presumed to have adverse effects on the insulin, blood sugar and hemoglobin levels, particularly on insulin-resistant or diabetic patients. It is thought to contribute to diabetes, though not proven clinically till date. In addition to all these groups of people, pregnant and breastfeeding women are also advised to refrain from using glucosamine.

Till now, the use of glucosamine has been shown to be safe as per clinical results and it is also approved as a medical drug in Europe. However, in the United States, it is not permitted for medical use by the Food and Drug Administration, and is classified as a dietary supplement. The results of different clinical tests to find out the potential of glucosamine in medical therapy are conflicting in nature and have given rise to many controversies. Therefore, some concrete studies are the need of the hour, to prove the efficacy of this compound as a medicine, which if proved, would definitely bring much relief to osteoarthritis patients.