Participants in one group were provide glucosamine in diet lemonade. There was no difference in knee pain, degradation of cartilage or bone marrow lesions between those who took the supplement and those ingesting a placebo. (CBC)

The use of a glucosamine supplement orally does not help in decreasing knee pain or lessen cartilage deterioration among people with chronic knee pain, says a new study.

Glucosamine is the second most commonly-used natural product to treat joint pain and arthritis. Previous reports have tallied global sales of the supplement at more than $2 billion. Chondroitin is another popular product.

The double-blind, placebo-controlled trial by researchers at the University of Arizona is published in Arthritis & Rheumatology.

The researchers say its the first study to investigate whether a glucosamine supplement helps with knee pain, prevents the worsening of cartilage damage or improves bone marrow lesions – which are thought to be the source of pain in those with osteoarthritis.

Osteoarthritis affects an estimated three million people, which amounts to roughly one in 10 Canadians, according to the Arthritis Society.

Dr. C. Kent Kwoh enrolled 201 people with mild to moderate pain in one or both knees in his study. The participants, aged 35 to 65, were recruited from physician offices and the University of Pittsburgh Arthritis Registry.

They were split into two groups:

  • Those treated daily with 1500 mg of glucosamine hydrochloride in a 16-oz bottle of diet lemonade.
  • Those treated with a placebo.

During a 24-week period, the participants were followed up with phone calls every four weeks. At the end of that period, they all underwent an MRI to assess the cartilage damage in their knees.

Researchers assessed both groups on four things:

  • knee pain.
  • degradation of cartilage.
  • bone marrow lesions.
  • the excretion of CTX-11 in urine.

Researchers discovered that there was no difference in any of those characteristics between the group that took the glucosamine and the group that had the placebo.

The urinary excretion of C-telopeptdes of type II collagen (CTX-11) is a predictor of cartilage destruction. Researchers found that there was no decrease in that either.

“Our study found no evidence that drinking a glucosamine supplement reduced knee cartilage damage, relieved pain, or improved function in individuals with chronic knee pain,” concluded Dr. Kwoh in his study.

The study was funded by The National Institute of Arthritis, Musculoskeletal and Skin Diseases, the Beverage Institute for Health & Wellness and The Coca-Cola Company, which provided the lemonade.