Everything you ever wanted to know about Glucosamine.

Glucosamine, a commonly used dietary supplement, is often found in various joint health products in combination with other dietary supplements. Glucosamine supplements are primarily used by people who suffer from arthritis or who take the supplement to maintain their joint health. Since consumer use of glucosamine is increasing, it’s important that consumers are well informed about the different types of glucosamine as well as the latest research on glucosamine.

In a recent article which was published in the medical journal, Osteoarthritis and Cartilage, (Hopman et al, 2006), the study authors noted that glucosamine use was increasing dramatically in Canada and they sought to find out which factors were associated with glucosamine use. Not surprisingly, they found that glucosamine use was higher among the elderly as the incidence of arthritis increases dramatically with age. They also noted that glucosamine use was higher among people who take calcium supplements, engage in physical activity, or who have a prior history of glucosamine use. Many of these factors seem to fit the pattern of people who are taking proactive measures to maintain their joint health.

There are three main types of glucosamine currently on the market:
1. Glucosamine Sulfate--This is the most researched type of glucosamine and has the largest amount of clinical trial data supporting its efficacy.
2. Glucosamine Hydrochloride--Many suppliers of this ingredient tout it as having a "lower molecular weight" and concluded that it is therefore "better absorbed" than glucosamine sulfate. However, in the largest study on glucosamine hydrochloride, which was independently funded by the NIH, glucosamine hydrochloride failed to show any benefits over placebo (Clegg et al, 2006). Many researchers have hypothesized that the sulfate moiety or component plays an important role in the activity of glucosamine.
3. N-acetyl glucosamine--there is sparse clinical trial data on this type of glucosamine and it is not commonly used by manufacturers.

In this recent article, published in the medical journal, Arthritis and Rheumatism (Vlad et al, 2007), the study authors sought to explain the heterogeneity of clinical trial results on glucosamine. Essentially, they endeavored to explain why many randomized clinical trials on glucosamine have found that it works, yet some clinical trials have conflicting results. Essentially, part of the reason for this discrepancy is that the clinical trials on glucosamine products include trials on glucosamine sulfate and glucosamine hydrochloride. Among their explanations for the heterogeneity of clinical trial results was the simple conclusion that "glucosamine hydrochloride is not effective."


Does glucosamine actually work?
Herrero-Beaumont et al (2007), conducted a recent study which involved 318 patients who were enrolled in a double-blind, randomized control trial for patients with knee osteoarthritis (OA) during a six month treatment course. The study itself compared glucosamine sulfate treatment not only to placebo, but additionally to acetaminophen in these patients. The study found that glucosamine sulfate is more effective than placebo in treating knee OA symptoms including pain and stiffness. The study findings reached the level of statistical significance over a 6 month period. What’s interesting about this study is that Acetaminophen actually failed to show a statistically significant effect when compared to placebo for treating OA pain.

What is the latest theory on how glucosamine actually works?
A recent study (Menis et al, 2007) reveals one potential mechanism through which sulfated glucosamine may act to suppress osteoarthritis. This particular study highlights the antioxidant activity of sulfated glucosamine on reducing oxidative stress in chondrocytes (cartilage cells). The study authors concluded, “…it is suggested that potential effects of sulfated glucosamine in controlling osteoarthritis might be partly via mechanisms involving direct scavenging of cellular radical species and alteration of oxidation mediated destructive events" (Menis et al, 2007). The implications of this study include the possibility that glucosamine may actually reduce cellular damage caused by oxidative stress on chondrocytes and therefore potentially act not only as a symptom modifying agent, but more importantly as a disease modifying agent in the treatment of osteoarthritis. To clarify, this means that glucosamine sulfate may not only improve osteoarthritis symptoms including pain or stiffness, but may actually slow the progression of the disease.

Is glucosamine use safe in people with diabetes?
Many joint health products, including Arthroleve, which contain glucosamine sulfate caution use in people who have diabetes. The reason for this caution is that glucosamine is actually a type of sugar which could theoretically affect blood sugar levels. However, though this is a theoretical concern, a recent clinical trial on glucosamine use in patients with diabetes concluded, "oral glucosamine at standard doses for 6 weeks does not cause or significantly worsen insulin resistance or endothelial dysfunction in lean or obese subjects" (Muniyappa et al, 2006).


References:


1. Clegg DO, Reda DJ, Harris CL, Klein MA, O'Dell JR, Hooper MM, Bradley JD, Bingham CO 3rd, Weisman MH, Jackson CG, Lane NE, Cush JJ, Moreland LW, Schumacher HR Jr, Oddis CV, Wolfe F, Molitor JA, Yocum DE, Schnitzer TJ, Furst DE, Sawitzke AD, Shi H, Brandt KD, Moskowitz RW, Williams HJ. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006 Feb 23;354(8):795-808.

2. Herrero-Beaumont G, Ivorra JA, Del Carmen Trabado M, Blanco FJ, Benito P, Martín-Mola E, Paulino J, Marenco JL, Porto A, Laffon A, Araújo D, Figueroa M, Branco J. Glucosamine sulfate in the treatment of knee osteoarthritis symptoms: a randomized, double-blind, placebo-controlled study using acetaminophen as a side comparator. Arthritis Rheum. 2007 Feb;56(2):555-67.

3.Hopman WM, Towheed TE, Gao Y, Berger C, Joseph L, Vik SA, Hanley DA, Carran J, Anastassiades T. Prevalence of and factors associated with glucosamine use in Canada. Osteoarthritis Cartilage. 2006 Dec;14(12):1288-93. Epub 2006 Jul 10

4. Mendis E, Kim MM, Rajapakse N, Kim SK. Sulfated glucosamine inhibits oxidation of biomolecules in cells via a mechanism involving intracellular free radical scavenging. Eur J Pharmacol. 2007 Oct 25;

5. Muniyappa R, Karne RJ, Hall G, Crandon SK, Bronstein JA, Ver MR, Hortin GL, Quon MJ. Oral glucosamine for 6 weeks at standard doses does not cause or worsen insulin resistance or endothelial dysfunction in lean or obese subjects. Diabetes. 2006 Nov;55(11):3142-50.

6. Vlad SC, LaValley MP, McAlindon TE, Felson DT. Glucosamine for pain in osteoarthritis: why do trial results differ? Arthritis Rheum. 2007 Jul;56(7):2267-77.