Safety assessment regarding use of glucosamine sulfate by patients whose dietary potassium intake is restricted

Hyperkalemia is common in patients with renal disease, and is sometimes caused by dietary potassium intake. We aimed to determine and compare the content of potassium in nine brands of glucosamine supplements sold in the Japanese market and via the Internet. The potassium content was 0.165-3 mg per daily dose in Japanese products, which contained glucosamine hydrochloride or N-acetylglucosamine, while the content in foreign products, in which glucosamine was sulfated, was 197-280 mg. Our results show that the potassium content in glucosamine sulfate supplements can correspond to 20% of the maximum daily intake of potassium by patients on hemodialysis, because the products sometimes contain glucosamine as glucosamine sulfate potassium chloride for stabilization. Although it is not permitted to sell glucosamine sulfate as food in Japan, consumers can easily buy foreign products that contain glucosamine sulfate via the Internet, and those products rarely indicate the potassium content. Health professionals should pay attention to patients' use of glucosamine supplements, especially when patients' dietary potassium intake needs to be restricted.