Intake of Chicken Leg Peptides Improves Quality of Life by Relieving Mild Knee Pain ―A Randomized, Double—blind, Placebo—controlled Clinical Trial―

Objective　This study was aimed to evaluate the effect of oral intake of chicken leg peptides （CLP）on knee pain. Methods　This was a 12-week, randomized, double-blind, placebo-controlled clinical trial. The subjects were 26 healthy Japanese adults with mild knee pain but no osteoarthritis. The subjects were randomly divided into two groups: the CLP intake group（47.7 mg/day of CLP） and the placebo group. Knee pain, functional impairment of the knee, and the associated limitation on daily activities were evaluated using the Japanese Knee Osteoarthritis Measure （JKOM）. The safety of long-term CLP intake was assessed by urine and blood tests. Results　Compared to the placebo group, the CLP group showed significant improvement in JKOM Question-7（Do you have pain in your knees when bending to the floor or standing up?） and Question-20（Were things that you usually do［some kind of lesson, meeting friends, etc.］ difficult because of knee pain during the last one month?）. Furthermore, oral intake of 47.7 mg of CLP daily for 12 weeks showed no significant adverse effects in urine and blood tests. Conclusions　Oral intake of CLP for 12 weeks could relieve mild knee pain and improve subjectsʼ quality of life. The safety of long-term intake of CLP was also confirmed.