Canberra Australian researchers have debunked fish oil and vitamin D as treatments for knee osteoarthritis in a clinical trial. The Australian team, from the University of Tasmania's Menzies, found that vitamin D and fish oil, both widely to slow knee cartilage loss and and reduce inflammation, had no distinguishable impact on knee osteoarthritis, Xinhua news agency reported. Knee osteoarthritis affects about 10 percent of men and 13 percent of women over the age of 60. Apart from joint-replacement surgery and general pain killers, there is no medical cure for the chronic disease. In the study, published in the world-renowned Journal of the American Medical Association (JAMA) on Thursday, the Australian experts divided a group of 413 sufferers in half and prescribed the first group vitamin D tablets and the other a placebo. After two years, the researchers re-examined the participants and found no discernable difference in knee degeneration between the groups. "This data suggests a lack of evidence to support vitamin D supplementation for slowing disease progression or reducing knee pain in osteoarthritis," Ding Changhai, study's lead author, said on Thursday. "Our study is the largest in the world to examine the potential effect of vitamin D supplementation on knee osteoarthritis", he added. In an earlier research study, the Tasmania crew also cast doubt on the widely accepted claim that fish oil acted as an effective treatment for the knee condition. They found that those given a low dose of fish oil, combined with Sunflower or sunola oil, for two years exhibited less pain and improved knee function than those who took a higher dose. "This shows us that fish oil is ineffective for osteoarthritis symptoms," Menzies Professor Graeme Jones, who oversaw the second study, said on Thursday. "To our surprise, the comparison oil was more effective for pain probably due to the sunola component, suggesting a benefit for a high oleic acid content", he said. Despite vitamin D and fish oil failing to live up to their tag as a cure-all for knee osteoarthritis, Jones said it was important to recognise they still improved overall bone health.