Effects of Non-Essential Amino Acids on Knee Joint Conditions in Adults: A Randomised, Double-Blind, Placebo-Controlled Trial

Abstract

Joint problems impair performance during exercise and daily activities and influence quality of life. The present study aimed to examine the effects of a combination of six non-essential amino acids (6AA) on joint conditions in an adult population. A total of 50 participants aged between 20 and 64 years with joint discomfort but no diagnosed joint disorder were randomly and blindly assigned to a control or 6AA group. The 6AA group took 12 g of the non-essential amino acid formulation orally (4 g three times a day) and the control group took equivalent doses of a placebo. Each group maintained the daily dose for 12 weeks. Primary outcome measures were evaluated with the visual analogue scale (VAS), the Japanese Knee Osteoarthritis Measure (JKOM), and the Japanese Orthopaedic Association score (JOA). These tests were taken before the experiment began at 4 weeks and 12 weeks after the intervention. The results of the VAS indicated that 6AA improved joint pain, discomfort, and stiffness both during a resting state and during normal activity. Participants’ scores on the JKOM and JOA also showed significant improvements in the group that had taken the 6AA supplement. These results demonstrate that 6AA improves symptoms of joint problems, such as pain, discomfort, stiffness, and difficulty in performing daily activities after 4 weeks of daily consumption.

Personalized Nutritional Strategies to Reduce Knee Osteoarthritis Severity and Ameliorate Sarcopenic Obesity Indices: A Practical Guide in an Orthopedic Setting

“…To the best of our knowledge, no study is available on the effect of non-EAA supplementation on KOA or SO. However, a recent randomized, double blind, placebo-controlled trial examined the effects of a combination of six non-EAAs (alanine, aspartic acid, glutamic acid, glycine, proline and serine) in an adult population with knee joint discomfort but with no clear diagnosis (i.e., KOA) in comparison with the placebo group [ 84 ]. The first group took 12 g of the non-EAA formulation orally (4 g, three times a day) for a period of 12 weeks, while the control group took equivalent doses of a placebo.…”

“…The first group took 12 g of the non-EAA formulation orally (4 g, three times a day) for a period of 12 weeks, while the control group took equivalent doses of a placebo. Symptoms were evaluated through validated questionnaires at baseline, 4 and 12 weeks [ 84 ]. The non-EAA group reported significant improvements in joint pain, discomfort, and stiffness, both during the resting state and during normal activity after four weeks of supplementation [ 84 ].…”

“…Symptoms were evaluated through validated questionnaires at baseline, 4 and 12 weeks [ 84 ]. The non-EAA group reported significant improvements in joint pain, discomfort, and stiffness, both during the resting state and during normal activity after four weeks of supplementation [ 84 ]. This result is of particular interest with regard to the population with no evident KOA (i.e., Grade 0); however, they were referred to the orthopedic specialist for joint symptoms from prevention prescriptive ( Table 2 ; Figure 2 ).…”