This edition highlights four recent studies involved in various aspects of collagen research, including exercise recovery, protein synthesis, and skin health.

Coingestion of collagen with whey protein prevents postexercise decline in plasma glycine availability in recreationally active men 

Muscle protein synthesis rates increase with exercise and by ingesting protein during recovery, however, muscle collagen or connective protein synthesis depends largely on the type of protein consumed. Collagen is a protein that is rich in glycine and proline and these amino acids help to increase connective protein synthesis when consumed during exercise recovery. A clinical study was conducted with 15 healthy young men to determine the effect of a combination of collagen and whey protein on muscle protein synthesis during exercise recovery. The crossover study was double-blind, randomized, and controlled. The participants consumed four study products: 30 g of whey protein (WHEY), 25 g whey and 5 g collagen (WC05), 20 g whey and 10 g collagen (WC10), and 15 g whey and 15 g collagen (WC15), immediately after a single bout of resistance exercise. Participants were instructed to refrain from strenuous physical activity and consumption of alcohol for 2 days before each study visit. All participants completed the same testing on each of the 4 test days, with only the study product being different each time. A blood sample was collected from participants at baseline, followed by  a 5-minute warmup  on a cycle ergometer, and thereafter, leg press and  extension exercises were completed. Various intensities of exercises were used, and participants were instructed to continue repetitions until failure, with 2-minute rest periods in between sets. After another blood sample collected immediately after cessation of exercise, participants were then instructed to consume the assigned investigational product. Additional blood samples were collected at 12 different timepoints throughout  the postprandial period. The results of the study showed that participants  who consumed 25 g of whey and 5 g of collagen prevented a decline in plasma glycine availability, while those who consumed 30 g of whey protein experienced a decline in glycine availability. Further research  is required to determine if the combination of protein and collagen does result in increased connective and myofibrillar protein synthesis.  

Access to the study: https://pubmed.ncbi.nlm.nih.gov/38604602/ 

Reference: Aussieker, T., Janssen, T. A. H., Hermans, W. J. H., Holwerda, A. M., Senden, J. M., van Kranenburg, J. M. X., Goessens, J. P. B., Snijders, T., & van Loon, L. J. C. (2024). Coingestion of collagen with whey protein prevents postexercise decline in plasma glycine availability in recreationally active men. International journal of sport nutrition and exercise metabolism, 34(4): 189–198. https://doi.org/10.1123/ijsnem.2023-0264 

The collagen synthesis response to an acute bout of resistance exercise is greater when ingesting 30 g hydrolyzed collagen compared with 15 g and 0 g in resistance-trained young men 

Skeletal muscle and tendons generate and transmit force to our bones, enabling movement. Athletes often sustain soft-tissue injuries, with muscle weakness being the most common risk factor. Risk of soft-tissue injuries may be mitigated by performing chronic resistance exercise using progressive overload to strengthen the muscles. Tendons also adapt to this activity by hypertrophying and increasing stiffness, which has a higher loading capacity. The combination of exercise and ingestion of vitamin C-enriched collagen significantly impacts collagen synthesis in the body. This double-blind, randomized, crossover design study was conducted in 10 healthy young males. The participants performed resistance exercise four times per week and were assigned to consume three different products on three separate testing days, with a 7-day washout period between each testing day. These products contained 50 mg of vitamin C and either 0 g, 15 g, or 30 g of hydrolyzed collagen. Blood samples were collected at baseline and at seven additional timepoints. The study showed that a single bout of high-intensity resistance exercise while supplementing, combined with 30 g of hydrolyzed collagen supplementation, increased whole-body collagen synthesis more than the other two groups. Further studies are required to determine whether prolonged use of hydrolyzed collagen will impact collagen synthesis in the same way.  

Access to the study: https://pubmed.ncbi.nlm.nih.gov/38007183/ 

Reference: Lee, J., Tang, J. C. Y., Dutton, J., Dunn, R., Fraser, W. D., Enright, K., Clark, D. R., Stewart, C. E., & Erskine, R. M. (2024). The collagen synthesis response to an acute bout of resistance exercise is greater when ingesting 30 g hydrolyzed collagen compared with 15 g and 0 g in resistance-trained young men. The Journal of nutrition, 154(7): 2076–2086. https://doi.org/10.1016/j.tjnut.2023.10.030 

The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial 

Older individuals experience less muscle protein synthesis in response to common anabolic stimuli such as protein ingestion and resistance exercise, which is referred to as age-related muscle anabolic resistance. The decline in physical mobility and health is partly due to the gradual loss of skeletal muscle mass and function, which is known as sarcopenia. Sarcopenia increases the risk of mobility limitations, falls, fractures, hospitalization, and frailty. If sarcopenia is not addressed, older individuals may become physically dependent sooner, relying on caregivers, and subsequently their quality of life may significantly worsen. Interventions targeting sarcopenia may help extend healthspan and promote physical mobility. In this double-blind, randomized, controlled study, 31 healthy older males were required to consume a controlled diet with protein intake set at the recommended dietary allowance (RDA). Participants were assigned to consume an additional 50 g of whey, pea, or collagen protein each day during the study period. This study showed that consuming high-quality protein (whey and pea) enhanced muscle protein synthesis compared to consuming only the protein level indicated by the RDA. However, collagen supplementation did not increase muscle protein synthesis, likely due to collagen’s low leucine content. This demonstrates  that while collagen supplementation has other benefits, it is ineffective at supporting muscle synthesis in older adults.  

Access to the study: https://pubmed.ncbi.nlm.nih.gov/38762187/ 

Reference: McKendry, J., Lowisz, C. V., Nanthakumar, A., MacDonald, M., Lim, C., Currier, B. S., & Phillips, S. M. (2024). The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial. The American journal of clinical nutrition, 120(1): 34–46. https://doi.org/10.1016/j.ajcnut.2024.05.009 

The effects of dietary supplementation with collagen and vitamin C and their combination with hyaluronic acid on skin density, texture and other parameters: A randomized, double-blind, placebo-controlled trial 

Recognizing the connection between nutrition and skin health, including its various aspects such as beauty, integrity, and the aging process, has sparked increased interest in using dietary interventions to achieve a more youthful appearance. Collagen supplementation has become popular due to its potential to boost the production of extracellular matrix (ECM) constituents, including collagen and hyaluronic acid (HA), and to prevent their breakdown by matrix metalloproteinases. Several studies have investigated the effects of collagen peptides on skin condition, demonstrating the potential to improve skin quality in various applications. This study was conducted as a three-way, randomized, placebo-controlled, double-blind study. Participants were randomly assigned to one of three groups: a daily dose of 5 g hydrolyzed collagen with 80 mg vitamin C (CP group), and additionally, 30 mg of HA (CPHA group), or a placebo group, consumed for  16 weeks. The objective of the study was to determine whether the addition of 30 mg of HA further improved skin parameters compared to collagen and vitamin C alone. Both products (CP and CPHA) showed some effectiveness for reducing skin roughness, and wrinkle severity compared to placebo. There were also significant reductions in wrinkle volume, maximum depth, and indentation index, however there was no difference between the two investigational products in these scores. There was also no significant difference in efficacy between CP and CPHA products, concluding that there are no apparent benefits to adding HA to collagen for improving skin texture or wrinkles. There were no observed effects on skin elasticity or hydration as a result of supplementation with any of the products.  

Access to the study: https://pubmed.ncbi.nlm.nih.gov/38931263/ 

Reference: Žmitek, K., Žmitek, J., Hristov, H., Rogl Butina, M., Keršmanc, P., & Pogačnik, T. (2024). The effects of dietary supplementation with collagen and vitamin C and their combination with hyaluronic acid on skin density, texture and other parameters: A randomised, double-blind, placebo-controlled trial. Nutrients, 16(12): 1908. https://doi.org/10.3390/nu16121908 

Bottom Line  

Collagen is the most abundant protein in the human body and a predominant component of tendons and ligaments. It plays a crucial role in the structural, mechanical, organizational, and tissue-building properties of the body. There is increasing evidence demonstrating the positive effects of collagen supplementation on skin and musculoskeletal health. As a result, collagen is considered a beneficial ingredient in food, pharmaceutical, and cosmetic products.