SAFETY

An abstract of a paper presented at a meeting of the American College of Rheumatology in November 2005 suggests that in normoglycemic individuals, GLUCOSAMINE salts do not present a clinical problem. In subjects with an abnormal oral glucose tolerance test, the average value went from 145 to 191 mg minute/ml when the GLUCOSAMINE salt was co-administered. Individual data were not given. One of two subjects with an abnormal oral glucose tolerance test became diabetic on the co-administration of a single dose of GLUCOSAMINE sulfate. However, this small study offers no basis for predicting the rates in a larger study (see Biggee 2007 for the full paper).

A basic study of insulin release in the rabbit pancreas found that N-acetylGLUCOSAMINE, at a concentration of 15 mg/mL, did not affect glucose-stimulated insulin release under high or low glucose conditions. In contrast, GLUCOSAMINE hydrochloride, at a concentration of 4 mg/mL, inhibited glucose-stimulated insulin release under high-glucose conditions (3 mg/mL) but not under low-glucose conditions (0.6 mg/mL).

In humans, an infusion of 100 grams of N-acetyl-D-GLUCOSAMINE did not result in an increase in blood glucose. Insulin injection did not alter the clearance of N-acetyl-D-GLUCOSAMINE, suggesting that N-acetylGLUCOSAMINE does not use the insulin-sensitive transporters used by glucose (see Gaulden 1964).

No. Benefits of chondroitin could likely be achieved by using additional GLUCOSAMINE according to the science:

Combination products with chondroitin usually contain the same amount of GLUCOSAMINE as the GLUCOSAMINE-only product and, in addition, have 400 milligrams or more of chondroitin. Thus, the total amount of sugar amines consumed is almost doubled. We believe the same goals can be accomplished by giving more GLUCOSAMINE.

Chondroitin sulfate is a co-polymer of N-acetylgalactosamine and glucuronic acid. N-acetylgalactosamine is an epimer of N-acetylGLUCOSAMINE (the –OH on carbon 4 is flipped in a different plane). All cells have epimerases, which can interconvert N-acetylGLUCOSAMINE and N-acetylgalactosamine (meaning one -OH is flipped in a different plane).

Chondroitin is a high-molecular-weight polymer, which is not absorbed as an intact molecule. Individual molecules of N-acetylgalactosamine and glucuronic acid are probably the largest units that are absorbed from the gut.

Thus, the combination product GLUCOSAMINE and chondroitin supplies more GLUCOSAMINE equivalents (N-acetylgalactosamine or N-acetylGLUCOSAMINE) than GLUCOSAMINE-only products, with only half as much amine sugars.