Regular collagen peptide administration exerts anti-obesity effects in high-caloric diet-fed rodents-a systematic review with meta-analysis of animal trials

BACKGROUND: Cost-effective and easy-to-implement nutritional approaches to overcoming obesity and accompanying diseases remain of considerable therapeutic interest. Collagen peptides (CP) have previously demonstrated potential to alleviate obesity and related symptoms during high-fat/ high-caloric diets. Therefore, a systematic review and meta-analysis have been conducted to pool the evidence from the last decades.

METHODS: A systematic literature search was conducted in accordance with the PRISMA statement in PubMed, Scopus, CINAHL, MEDLINE and ScienceDirect in March 2024. Risk of bias was assessed using the SYRCLE tool for animal studies. A random-effects model with standardized mean differences (SMD) calculated overall effect sizes. Preclinical controlled trials as well as randomized controlled trials were eligible if rodents received a high-fat or high-caloric diet, were genetically not modified and administered CPs compared to a placebo for at least 3 weeks.

RESULTS: Twenty-one and nineteen (n = 339) studies were included in the systematic review and meta-analysis, respectively. A several-week CP supplementation led to significant decreases in body mass (p < 0.01; SMD = -1.87), food intake (p = 0.01; SMD = -1.43), glucose metabolism (p < 0.02; SMD = -2.21), adipose tissue & organ content (p < 0.01; SMD = -1.26), LDL (p < 0.01; SMD = -2.02), triacylglycerol (p < 0.01; SMD = -2.16) and leptin (p = 0.01; SMD = -1.33). Significant increases were observed in HDL (p = 0.04; SMD = 1.14) and adiponectin (p < 0.01; SMD = 1.04). A moderate to high risk of bias, combined with a very low certainty of evidence for each parameter, was apparent.

CONCLUSION: CP administration in rodents with obesity for at least 3 weeks demonstrated significant anti-obesity effects by positively influencing body mass, food intake, glucose metabolism, lipid markers, adipose tissue and adipokines. However, CP's anti-obesity effects in humans remain largely unexplored, necessitating further research.