Collagen powder absorption and bioavailability
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Collagen Powder Absorption: Key Amino Acids and Peptide Forms
Collagen powder, when ingested, is broken down into amino acids and small peptides, which are then absorbed into the bloodstream. The main amino acids from collagen—glycine, proline, and hydroxyproline—show significant increases in plasma concentration after oral intake, indicating effective absorption. Notably, collagen is absorbed both as free amino acids and as small peptides, such as dipeptides and tripeptides, with a substantial portion entering the bloodstream in peptide form rather than as single amino acids 13469.
Bioavailability of Collagen Peptides: Influencing Factors
Hydrolysis and Molecular Size
Enzymatic hydrolysis of collagen enhances the absorption rate and bioavailability of its key amino acids, especially glycine, proline, and hydroxyproline, compared to non-hydrolyzed forms. This means that hydrolyzed collagen powders are more efficiently absorbed and utilized by the body . Smaller peptides, such as dipeptides and tripeptides, are absorbed more rapidly and efficiently in the small intestine, while larger peptides face more degradation and have lower bioavailability 59.
Peptide Transport and First-Pass Metabolism
After digestion, collagen-derived peptides are transported across the intestinal wall, with most showing good bioavailability (over 10%). Some peptides, like Gly-Pro-Hyp, are more efficiently transported depending on the collagen source. The liver also plays a role in modifying these peptides before they reach systemic circulation, a process known as first-pass metabolism 26.
Food Matrix and Delivery Systems
The matrix in which collagen is consumed can affect absorption. For example, collagen hydrolysate added to fermented milk products results in higher plasma concentrations of key amino acids compared to collagen dissolved in water, likely due to improved stability and absorption in the digestive tract . Additionally, encapsulation systems—such as microcapsules, hydrogels, and nanoliposomes—can protect collagen peptides from degradation in the gut and enable sustained release, further enhancing bioavailability 510.
Absorption Dynamics: Peptide Size and Circulation
Collagen peptides larger than tripeptides can also be absorbed and detected in the bloodstream, challenging the previous belief that only small peptides are bioavailable. Some studies have identified even larger peptides, such as pentadecapeptides, in circulation after oral collagen intake 36. However, small peptides still make up a significant portion of the absorbed collagen, and their rapid absorption can lead to quick but short-lived increases in blood levels 45.
Enhancing Collagen Bioavailability: Encapsulation and Controlled Release
Encapsulation technologies, such as chitosan microcapsules, have been shown to significantly increase the maximum concentration, area under the curve (AUC), and time to maximum concentration (tmax) of collagen peptides in the blood. These systems help control the release of peptides in the gastrointestinal tract, prolonging their presence in the bloodstream and potentially improving their physiological effects 510.
Conclusion
Collagen powder is effectively absorbed in the body, primarily as small peptides and amino acids, with hydrolyzed forms showing superior bioavailability. Factors such as peptide size, enzymatic hydrolysis, food matrix, and advanced delivery systems like encapsulation can further enhance absorption and bioavailability. Continued research and innovation in delivery methods are likely to improve the effectiveness of collagen supplements for health and wellness.
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