Aging is associated with decreased synthesis and increased degradation of muscle, bone, and connective tissue, leading to decrements in body wide structure and function. This depression in tissue turnover can lead to sarcopenia in skeletal muscle, and osteopenia/osteoporosis in bone, both of which are associated with increased injury risk and decreased function and are consequently widely studied. Surprisingly, age related losses in collagen is not well studied, even though it is the most abundant protein in the human body and a major constituent of muscle and bone. Collagen is not only a major component of the extracellular matrix (ECM), connecting muscles to bones, and bones to bones, but is also responsible for force transmission and locomotion. Additionally, age and activity related losses in collagen occur at a higher rate than muscle and bone, rendering collagen containing tissue, such as tendons and ligaments, more susceptible to injury. Injury to collagen containing tissue can lead to chronic inflammation and pain, resulting in decreased function and participation in sports. Approximately 19 % of the U.S. population is afflicted with chronic pain, with increasing incidence in active and aging populations. Pain can limit physical activity and activities of daily living (ADLs), resulting in declined mental, physical, and social health, as well as cause and proliferate disabilities. Long term pharmacological interventions to manage pain have negative side effects, which creates a need for alternative therapies. Currently, nutritional interventions for pain target inflammation or joint health, but few influence both. One such alternative therapy is supplementation with collagen peptides (CP). Supplementation of these peptides has shown positive effects on pain, function, and inflammation. The effects of collagen peptides on collagen containing tissue are thought to be due to bioactive peptides of the three main amino acids found in collagen—glycine, proline, and hydroxyproline—increasing collagen transcription and connective tissue repair. While short term studies have observed positive effect on pain and function, as well as body composition, a majority of the research has been conducted in diseased and injured populations, and few have assessed the effects of CP supplementation long term in healthy fit populations. PURPOSE: To determine the effects of daily CP consumption over 3, 6, and 9 months on a variety of measures of pain and function, range of motion, body composition, bone mineral density, inflammation, and bone and collagen turnover in healthy active older adults. METHODS: This study was a double-blind randomized control trial with three treatment groups (Placebo, 10 g/d, and 20 g/d). Survey measures of pain, range of motion, blood draws, and DXA to determine body composition and bone mineral density, were administered at baseline, 3 months, 6 months, and 9 months. Mixed model ANOVAs assessed group by time (baseline, 3 months, 6 months, and 9 months) interactions in all primary measurement outcomes. Additionally, the moderating effect of exercise frequency as well as sex differences were assessed. Significant interactions were further assessed via simple repeated measures ANOVA tests using Bonferroni corrections. RESULTS: Improvements in ADLs were observed with 10 g/d while, only slight differences were observed in the 20 g/d group over 6 months of supplementation. Pain was also reduced in the 10 g/d and 20 g/d groups over 6 months of supplementation, but only in high frequency exercisers. Additionally, survey measures of quality of life (QOL) related to mental health were improved in the 10 g/d group, while scores decreased in the 20 g/d group over 9 months of supplementation. The improvements in survey measures observed in the 10 g/d group were accompanied with favorable shifts in biomarkers, while few significant improvements were observed in the 20 g/d group, compared to the placebo group. Conclusion: These findings suggest that 10 g/d of CP supplementation for 3, 6, and 9 months compared to 20 d/g or placebo had benefits on ADLs, pain, mental health, and improvements in biomarkers of bone and collagen turnover, while 20 g/d seemed to not be as effective.
