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Glucosamine is a natural compound found in the human body, specifically an amino monosaccharide (a nitrogen-containing sugar). It is thought to possibly play a role in cartilage formation and repair and to perhaps have an anti-inflammatory affect within humans.
Glucosamine is also known as 2-amino-2-deoxy-glucose; 2-amino-2-deoxy-beta-D-glucopyranose; and chitosamine. The chemical symbol for glucosamine is C6H13NO5. It is sold as a nutritional or dietary supplement in three forms: glucosamine hydrochlo-ride (glucosamine HCl), glucosamine sulfate, and N-acetyl-glucosamine (NAG). Within scientific studies, there appears to be no difference between the three forms with regards to their effectiveness.
Glucosamine is found is various forms when it is sold commercially. Some of these forms include capsules (500 milligrams [mg], 550 mg, 750 mg, and 1,000 mg), liquid (500 mg per five milliliters), tablets (340 mg, 500 mg, and 1,000 mg), and powder.
When taken as anoral supplement, glucosamine is sometimes used in the treatment of a type of arthritis called osteoarthritis. Osteoarthritis is considered the largest and most widely occurring type of arthritis. Osteoarthritis, also called degenerative joint disease, is caused by deterioration or loss of cartilage at one or more joints of the body. The symptoms range from mild pain and stiffness to complete loss of use of the joint, and may or may not have an identifiable cause. Unlike the less common rheumatoid arthritis, osteoarthritis is not marked by inflammation. While osteoarthritis is commonly associated with overweight, cartilage deterioration can be caused by excessive wear and tear on the joints, which may be due to excessive physical exercise or exertion. People aged 60 years or older often have osteoarthritis. According to the U.S. Centers for Disease Control and Prevention (CDC), over 21 million people in the United States annually suffer with osteoarthritis.
The use of glucosamine in osteoarthritis therapy seems to be considered generally safe among medical professionals. However, it is not completely accepted within the medical community as being effective for osteoarthritis treatment. In the United States, the Food and Drug Administration (FDA) has not approved the use of glucosamine for medical use within humans. It is classified as a dietary supplement
so FDA approval is not needed as long as companies do not advertise it as a treatment for a medical condition. Instead, in the United States, glucosamine is a widely popular alternative medicine for the relief of joint pain. In Europe, however, the glucosamine-form glucosamine sulfate is approved as a medical drug.
Besides osteoarthritis, glucosamine is also used to relieve symptoms of leg pain, rheumatoid arthritis, inflammatory bowel disease (such as ulcerative colitis and Crohn’s disease), and temporomandibular joint (TMJ) disorders. Scientific results show some positive evidence for the effective use of glucosamine with osteoarthritis; however, the scientific evidence is much more unclear for the other diseases.
Glucosamine is taken from animal tissue, specifically from the shells of crabs, lobsters, and shrimp. Within these shellfish, glucosamine is made naturally in the form of glucosamine-6-phosphate, which eventually makes glycosaminoglycans, among other substances. Since glucosamine-6-phosphate helps to regulate the production of joint cartilage and glycosaminoglycans are a major component of cartilage, glucosamine may help to rebuild cartilage and treat arthritis. Whether these glu-cosamine processes could be involved in human arthritis remains undecided in the medical community. Not all medical professional believe glucosamine is effective
A typical dosage of glucosamine is 1,500 milligrams per day. The two most commonly sold forms are glucosamine sulfate and glucosamine hydrochlor-ide. Glucosamine is often sold in combination with other supplements such as chondroitin sulfate(a sul-fated glycosaminoglycan composed of a chain of alternating sugars) and methylsulfonylmethane (MSM, an organic sulfur compound within the chemical class of sulfones).
When glucosamine is taken orally into the body (as a pill), according to conclusions from scientifically based animal studies, it is absorbed into the small intestine. It then travels into the liver where most of it is metabolized. Based on these studies, some of it does apparently go to cartilage; however, it is not known how much is actually transmitted to joints. It is primarily removed from the body through urine.
Clinical studies have consistently showed that glucosamine is safe when used as directed. However, according to the National Institutes of Health (NIH), side effects may include drowsiness, headache, upset stomach, insomnia, skin reactions, light sensitivity, and nail toughening. Rare symptoms include abdominal pain, appetite loss, vomiting, nausea, intestinal gas, heartburn, and diarrhea.
The National Institutes of Health recently sponsored a large, multi-institutional clinical trial to test the effects of chondroitin sulfate, glucosamine, and the combination of the two on knee osteoarthritis. (Chondroitin is a carbohydrate that is a component of cartilage. It is thought to help promote water retention and elasticity in cartilage and help prevent enzymes from destroying cartilage.) The study is the largest of its kind to date with respect to research into the two substances.
The four-year study, known as Glucosamine/ chondroitin Arthritis Intervention Trial (GAIT), involved almost 1,600 participants and 16 research facilities. It was funded by the National Center for Complementary and Alternative Medicine and the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The lead researcher in the study was Daniel O. Clegg from the University of Utah, School of Medicine (Salt Lake City). Five different treatments were given daily for 24 weeks: glucosamine alone (1,500 mg), chondroitin sulfate alone (1,200 mg), glucosamine and chondroitin sulfate combined (same doses), a placebo, or celecoxib (200 mg) (a FDA-approved drug for osteoarthritis pain, and branded in the United States as Celebrex®).
According to the resulting 2006 article “Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis” in the New England Journal of Medicine,the six-month trial found that patients taking glucosamine, chondroitin sulfate, or a combination of the two had no significant decrease in their major osteoarthritis symptoms compared to patients taking a placebo. Patients who took celecoxib had a significant decrease in the severity of their symptoms. However, glucosamine and chondroitin sulfate together seemed to help people with pain classified as moderate-to-severe. With people in the mild pain group, glucosamine and chondroitin sulfate together or alone did not provide substantial relief.
For the most part, glucosamine does not show any contraindications with other drugs; that is, medical studies have not shown that it is harmful to users. Scientific studies have shown that the use of glucosamine (as directed) does not produce any serious, permanent problems.
Glucosamine taken above the recommended dosages could decrease the effectiveness of insulin or other such drugs that control blood sugar levels in diabetes. According to the NIH, some studies show a connection while other studies do not; however, the connection has been suggested as possible by the medical community.
Reports from the NIH suggest that glucosamine may also increase the risk of bleeding especially when taking aspirin, blood thinners, anti-platelet drugs, and non-steroidal anti-inflammatory drugs. The use of glucosamine has also been possibly linked to the increase in the frequency and severity of asthma.
Since glucosamine is not approved by the FDA, its safety and formulation is determined solely by the manufacturer. Thus, quality and content may vary among manufacturers. Tests have been performed by ConsumerLab.com, a leading provider of independent tests for nutritional and health products and services. Technicians at the laboratory report that the majority of companies manufacturing glucosamine for consumer use provide at least 90% of the amount of glucosamine stated on the label.
The Arthritis Foundation recommends that, if using glucosamine, consumers should buy from established companies (because they can more easily be held accountable for their products); read the product label carefully (if need be, ask the pharmacist questions); consult with the family doctor before trying new medicines; verify the source of the medical problem before beginning glucosamine; make sure the physician is aware of any future plans to take glucosamine; and do not reduce or eliminate prescription medicines one is already taking.
If deciding to take glucosamine, try it between six to eight weeks. It generally takes this amount of time before any noticeable effects are felt. Sometimes, no effects are felt. If a reduction of symptoms is not noticed at the end of this period of time, the Arthritis Foundation states that glucosamine will probably not help.
The use of alcohol, tranquilizers, sedatives, anti-seizure drugs, anti-anxiety drugs, muscle relaxants, and antihistamine medicines may intensify the drowsiness side effect that is possible with glucosamine. Thus, if taking glucosamine and any of these drugs together, users should be aware (and warned) that it may adversely affect one’s concentration. Consumers should talk with a medical professional before taking glucosamine.
People who are overweight, have diabetes, or liver disease should check their blood sugar levels more frequently when taking glucosamine because it is an amino sugar. If taking blood-thinning medication or daily aspirin therapy, blood clotting time should be tested more frequently.
A person can overdose on glucosamine. The amount of glucosamine varies with the supplemental form. Pure glucosamine hydrochloride is at a concentration of about 83% in the glucosamine base; pure glucosamine sulfate is approximately 65%, and pure N-acetyl glucosamine is around 75%.
According to the NIH, there is no scientific evidence to show that glucosamine should be given to children. Methylsulfonylmethane (MSM), which is sometimes packaged with glucosamine, has been shown to have a relationship with autism, but whether that association is good or bad is not currently known.
Osteoarthritis does affect children. Clinical studies have not proven whether or not glocosamine— either in children or adults—should be recommended as a medical therapy for osteoarthritis. Some studies show that glucosamine can help people with mild to moderate osteoarthritis and prevent the deterioration of cartilage. However, other studies do not show these benefits. The majority of studies have been performed with glucosamine hydrochloride and glucosamine sul-fate; but not with N-acetyl-glucosamine.
In any case, the effects of these glucosamine supplements on a growing child or developing baby are not yet known. For that reason, glucosamine is not recommended for, and should not be taken by, children. Because of the lack of long-term effects on a developing fetus and child, women who are pregnant and women who could become pregnant are advised by the Arthritis Foundation not to take glucosamine.
Bartlett, Susan J. Clinical Care in the Rheumatic Diseases. Atlanta, GA: Association of Rheumatology Health Professionals, 2006.
Imboden, John B, David B. Hellmann, and John H. Stone, eds. Current Rheumatology Diagnosis and Treatment. New York: Lange Medical Books/McGraw-Hill, 2004.
Clegg, D.O, et al. “Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis” New England Journal of Medicine. 354: 795–808, 2006.
Gray, H., P. Hutcheson, and R. Slavin. “Is glucosamine safe in patients with seafood allergy?” Journal of Allergy and Clinical Immunology. 114:459–460, 2004.
Hochberg, M.C. “Nutritional supplements for knee osteoarthritis—Still no resolution” New England Journal of Medicine. 354:848–850, 2006.
Efficacy of Glucosamine and Chondroitin Sulfate May Depend on Level of Osteoarthritis Pain. HIH News, National Institutes of Health. February 22, 2006 [Cited March 18, 2007]. <http://www.nih.gov/news/pr/feb2006/nccam-22.htm>.
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William Arthur Atkins.