Nutritional Ergogenic Aids: Introduction, Definitions and Regulatory Issues
Ira Wolinsky, Judy A. Driskell in Nutritional Ergogenic Aids, 2004
Glucosamine and chondroitin sulfate are publicized in the popular media as being capable of protecting joints and tendons and positively influencing osteoarthritis. Glucosamine is an amino monosaccharide found in cartilage, tendons and ligaments. Glucosamine is synthesized in the body from glucose and glutamic acid. It is available in supplemental form as glucosamine hydrochloride, glucosamine sulfate and N-acetyl-glucosamine. Chrondroitin sulfate, a glycoaminoglysan, found in articular cartilage, is available in supplemental form usually as mixtures of chrondroitin sulfate A and C. Both glucosamine and chondroitin sulfate have been reported to stimulate chon-drocyte growth in animals, though only equivocal reports exist for chondro-protection in humans. Evidence exists that combined preparations of glucosamine and chondroitin sulfate may be synergistic. Both supplements can be safely consumed, with some individuals experiencing mild digestive problems; the usual dosage is 1500 mg glucosamine and 1200 mg chron-droitin sulfate. Preliminary evidence exists that glucosamine and chron-droitin sulfate may improve symptoms of osteoarthritis at least as effectively as authorized nonsteriodal anti-inflammatory drugs. Thus, it is too early to recommend use of glucosamine and chondroitin sulfate to athletes as nutritional ergogenic aids.
Glycosaminoglycans
Luke R. Bucci in Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Research on the effects of glucosamine on a common injury seen in sports medicine — chondromalacia patellae — showed promising results, indicating that glucosamine may have broad applications for repair of cartilage, and perhaps other connective tissues, given the known mechanisms of action. All connective tissues and cells must synthesize hyaluronan, GAGs, and collagen in order to regenerate, repair, or produce extracellular matrix. Glucosamine offers a single agent that stimulates synthesis of all macromolecular components of cartilage. Thus, application to other degenerative joint diseases is a logical extension of the known properties of glucosamine. Any conditions that involve repair of cartilage and joints is an indication for glucosamine therapy. Such conditions would include osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, invertebral disc conditions, chondromalacia, tendinitis, bursitis, osteochondrosis, postsurgical repair of traumatic injury to joints, traumatic injury to joints, and tenosynovitis. Speculative uses would include repair of other connective tissues, such as tendon or ligament tears and repair, skin wound healing, and fracture repair.
Articular Cartilage
Manoj Ramachandran, Tom Nunn in Basic Orthopaedic Sciences, 2018
Nutritional supplements, especially those advertised as being beneficial to joints, constitute a multi-million-pound industry. Glucosamine is an amino-monosaccharide sugar and is a naturally occurring component of the glycosaminoglycans keratan sulphate and hyaluronate. Chondroitin is another glycosaminoglycan. Of these, glucosamine is the only substance to have been evaluated in clinical trials and to have shown some benefit. Produced either synthetically or from shells, glucosamine is sold as glucosamine sulphate and glucosamine hydrochloride. In vitro studies have demonstrated the effect of glucosamine in reversing the inhibition of proteoglycan synthesis by interleukin-1 (IL-1) and suppressing the inflammatory response of neutrophils. Several randomized studies have shown the efficacy of glucosamine in knee osteoarthritis, but the methodology and outcome measures used have been criticized widely in the literature. Nonetheless, it is likely that some benefit is obtained from glucosamine comparable to analgesic therapy, and in view of the very low risk of side-effects (shellfish allergy, occasional gastrointestinal symptoms) and the low cost of glucosamine, it is worth trying. Most trials used a dose of 1500 mg/day, but there is variety in the consistency of available formulations. Currently, glucosamine and chondroitin are not NICE-recommended (see Chapter 30).
Natural options for management of melasma, a review
Published in Journal of Cosmetic and Laser Therapy, 2018
Glucosamine is an amino-monosaccharide which is found in all human tissues. When an amino acid group is added to glucose, the result is the production of the sugar. The molecule product is then acetylated to N-acetyl glucosamine (66). N-acetyl glucosamine has been found to have lightening effects on hypermelanosis due to its reduction of melanin in the melanocytes by prevention of tyrosinase glycosylation (51,66). A recent randomized clinical trial (66) indicated that N-acetyl glucosamine combined with nicotinamide could be a good alternative to HQ when treating melasma. Results of this study demonstrated efficacy in both subjective and objective measures (Table 3). Subjects were instructed against direct sun exposure and daily use of sun protection factor, SPF 15. Combination of niacinamide and glucosamine has been found to have even better results compared to use of glucosamine alone (67).
Glucosamine for the Treatment of Osteoarthritis: The Time Has Come for Higher-Dose Trials
Published in Journal of Dietary Supplements, 2019
Mark F. McCarty, James H. O'Keefe, James J. DiNicolantonio
Despite the marked inconsistencies in the clinical research literature with glucosamine, there are ample grounds for suspecting that, in adequately potent doses, it is indeed useful in osteoarthritis. One key consideration is that the onset of pain relief with supplemental glucosamine is said to be gradual, taking several weeks to be most noticeable; when glucosamine is discontinued, pain may take a week or more to return (McCarty, 1994). This is not the pattern of benefit that one would expect to see with a placebo effect. Moreover, whereas there are some clinical trials reporting benefit and others failing to note benefit, where are the studies in which glucosamine performed worse than placebo? The fact that the commercial market for glucosamine supplements remains substantial despite the broad publicity given to negative clinical trials is consistent with the possibility that some people are indeed getting genuine benefit. The clear efficacy of glucosamine in animal models of arthritis, albeit usually at doses proportionately higher than those employed clinically, also suggests that glucosamine may have genuine clinical potential in arthritis. (Admittedly, some of these may be closer to rheumatoid arthritis in their pathogenesis than osteoarthritis, which brings up the interesting point that the only double-blind study to have tested glucosamine in patients with rheumatoid arthritis found that it did indeed confer some symptomatic benefit [Nakamura et al., 2007].)
What is the selection process for osteoarthritis pharmacotherapy?
Published in Expert Opinion on Pharmacotherapy, 2020
Shirley P. Yu, David J. Hunter
Nutraceuticals are popular with their direct marketing and labeling of the products stating its potential benefits for specific chronic conditions. The use of fish oil, vitamin D, glucosamine, chondroitin sulfate are all discouraged in OA guidelines. There is limited evidence of their efficacy in OA, and glucosamine, the most commonly used supplement is now strongly recommended against by OA guidelines [13]. There are concerning publication biases in glucosamine trials with a trend toward a larger effect size in industry-sponsored trials [39]. Lately, there has been more topical focus toward curcumin, the principal curcuminoid extracted from turmeric root (curcuma longa). Curumin is thought to be an inhibitor of nuclear factor-kappa β (NF- κβ) and may have pain reduction effects in OA. A recent double-blind multi-center, randomized placebo controlled trial of a bio-optimized curcuma longa extract showed a significant decrease in knee OA pain, with positive trends for Patient Global Assessment of Disease Activity and serum sColl2-1, a biomarker of cartilage degradation [40]. The study is of short duration with 150 participants, and further large-scale investigational trials are required before conclusive recommendations can be made for this nutraceutical.