Collagen Hydrolysates: A Source of Bioactive Peptides Derived from Food Sources for the Treatment of Osteoarthritis.

Osteoarthritis (OA) is the most common joint disorder, with a social and financial burden that is expected to increase in the coming years. Currently, there are no effective medications to treat it. Due to limited treatment options, patients often resort to supplements, such as collagen hydrolysates (CHs). CHs are products with low molecular weight (MW) peptides, often between 3 and 6 kDa, and are a result of industrialized processed collagen. Collagen extraction is often a by-product of the meat industry, with the main source for collagen-based products being bovine, although it can also be obtained from porcine and piscine sources. CHs have demonstrated positive results in clinical trials related to joint health, such as decreased joint pain, increased mobility, and structural joint improvements. The bioactivity of CHs is primarily attributed to their bioactive peptide (BAP) content. However, there are significant knowledge gaps regarding the digestion, bioavailability, and bioactivity of CH-derived BAPs, and how different CH products compare in that regard. The present review discusses CHs and their BAP content as potential treatments for OA.

A White Paper on Collagen Hydrolyzates and Ultrahydrolyzates: Potential Supplements to Support Joint Health in Osteoarthritis?

PURPOSE OF REVIEW: Osteoarthritis (OA) is the most common forms of arthritis in the general population, accounting for more pain and functional disability than any other musculoskeletal disease. There are currently no approved disease modifying drugs for OA. In the absence of effective pharmacotherapy, many patients with OA turn to nutritional supplements and nutraceuticals, including collagen derivatives. Collagen hydrolyzates and ultrahydrolyzates are terms used to describe collagens that have been broken down into small peptides and amino acids in the presence of collagenases and high pressure. RECENT FINDINGS: This article reviews the relevant literature and serves as a White Paper on collagen hydrolyzates and ultrahydrolyzates as emerging supplements often advertised to support joint health in OA. Collagen hydrolyzates have demonstrated some evidence of efficacy in a handful of small scale clinical trials, but their ability to treat and reverse advanced joint disease remains highly speculative, as is the case for other nutritional supplements. The aim of this White Paper is to stimulate research and development of collagen-based supplements for patients with OA and other musculoskeletal diseases at academic and industrial levels. This White Paper does not make any treatment recommendations for OA patients in the clinical context, but simply aims to highlight opportunities for scientific innovation and interdisciplinary collaboration, which are crucial for the development of novel products and nutritional interventions based on the best available and published evidence.

Assessment of Bioavailability after In Vitro Digestion and First Pass Metabolism of Bioactive Peptides from Collagen Hydrolysates.

Collagen hydrolysates (CHs) are composed of bioactive peptides (BAPs), which possess health enhancing properties. There is a knowledge gap regarding the bioavailability of these BAPs that involves intestinal transport and hepatic first pass effects. A simulated gastrointestinal model was used to generate digesta from two CHs (CH-GL and CH-OPT), which were applied to a novel transwell co-culture of human intestinal epithelium cell line-6 (HIEC-6) and hepatic (HepG2) cells to simulate in vivo conditions of absorption and first pass metabolism. Peptide transport, hepatic first pass effects, and bioavailability were determined by measuring BAPs (Gly-Pro, Hyp-Gly, Ala-Hyp, Pro-Hyp, Gly-Pro-Hyp) using an innovative capillary electrophoresis method. All peptides were transported across the intestinal cell layer to varying degrees with both CHs; however, Gly-Pro-Hyp was transported only with CH-GL, but not CH-OPT. Notable hepatic production was observed for Ala-Hyp with both CH treatments, and for Pro-Hyp and Gly-Pro with CH-GL only. All peptides were bioavailable (>10%), except for Gly-Pro-Hyp after CH-OPT. Overall, a high degree of transport and hepatic first pass effects on CH-derived BAPs were observed. Further research is needed to explore the hepatic mechanisms related to the production of BAPs and the bifunctional effects of the bioavailable BAPs noted in this study.

Gastrointestinal Digestion Model Assessment of Peptide Diversity and Microbial Fermentation Products of Collagen Hydrolysates.

Osteoarthritis (OA), the most common form of arthritis, is associated with metabolic diseases and gut microbiome dysbiosis. OA patients often take supplements of collagen hydrolysates (CHs) with a high peptide content. Following digestion, some peptides escape absorption to induce prebiotic effects via their colonic fermentation to generate short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs) and colonic gases (NH4 and H2S). The capacity of CHs to generate microbial metabolites is unknown. Proteomic analysis of two CHs (CH-GL and CH-OPT) demonstrated different native peptide profiles with increased peptide diversity after in vitro gastric and small intestinal digestion. Subsequent 24 h fermentation of the CH digests in a dynamic gastrointestinal (GI) digestion model containing human fecal matter showed that CH-OPT increased (p < 0.05) H2S, SCFAs (propionic, butyric and valeric acids), BCFAs, and decreased NH4 in the ascending colon reactor with no major changes seen with CH-GL. No major effects were observed in the transverse and descending vessels for either CH. These findings signify that CHs can induce prebiotic effects in the ascending colon that are CH dependent. More studies are needed to determine the physiological significance of CH-derived colonic metabolites, in view of emerging evidence connecting the gut to OA and metabolic diseases.

Effect of Non-Conventional Drying Methods on In Vitro Starch Digestibility Assessment of Cooked Potato Genotypes.

Potatoes (Solanum tuberosum L.) are a good dietary source of carbohydrates in the form of digestible starch (DS) and resistant starch (RS). As increased RS content consumption can be associated with decreased chronic disease risk, breeding efforts have focused on identifying potato varieties with higher RS content, which requires high-throughput analysis of starch profiles. For this purpose, freeze drying of potatoes has been used but this approach leads to inaccurate RS values. The present study objective was to assess the starch content (RS, DS and total starch (TS)) of three cooked potato genotypes that were dried using freeze drying and innovative drying techniques (microwave vacuum drying, instant controlled pressure drop drying and conductive hydro-drying) relative to freshly cooked potato samples. Depending on the genotype, all drying methods showed one or more starch measures that were significantly different from freshly cooked values. The combination of ultrasound and infrared assisted conductive hydro-drying was the only method identified to be associated with accurate assessment of DS and TS content relative to fresh samples. The drying treatments were all generally associated with highly variable RS content relative to fresh controls. We conclude that freshly cooked samples must be used for selecting varieties with a high proportion of RS starch as drying of cooked potatoes leads to unreliable RS measurements.

Freeze-drying affects the starch digestibility of cooked potato tubers.

Freeze-drying (FD) has utility for phytonutrient screening but its reliability for starch measurements is unclear. The impact of FD was tested on total (TS), digestible (DS) and resistant starch (RS) for four potato varieties (PC Red, GG Red, GG Yellow, and Dolbec Yellow). The treatments included: (a) tubers boiled and then cooled for 1h at room temperature (RT) (control; Treatment 1) and 24h at 4°C; (b) tubers boiled and then cooled for 1h at RT with subsequent FD (Treatment 2); and (c) raw tubers that underwent FD, then were rehydrated, boiled, and cooled for 1h at RT (Treatment 3). TS and DS content did not differ between the control samples cooled for 1h or 24h with Treatment 1 but RS content at 24h was higher, which indicated starch retrogradation. Cultivar variations were observed in the percent increase in RS between 24h vs. 1h with the greatest increase in Dolbec Yellow (114.5±7.6%). Relative to controls, FD treatments modified measured TS content in three of four varieties including overestimation by 94.2±6.5% and 156.0±5.2% for GG Yellow with Treatments 2 and 3, respectively. FD caused overestimation of DS and underestimation of RS in the same three varieties relative to controls including overestimation of DS in GG Yellow by 122.9±4.7% (Treatment 2) and 205.7±13.8% (Treatment 3). PC Red showed the greatest underestimation in RS content compared to controls of 42.5±9.6% and 61.7±5.4% in Treatment 2 and 3, respectively. Modifications to cooking and rehydration procedures following FD of raw tuber samples did not improve reliability of TS, DS, and RS measurements. Microscopy showed that cells remained intact following cooking whereas cell wall integrity was reduced when FD followed cooking and that cooking followed by FD led to destruction of cellular structure. We conclude that FD leads to unreliable starch measurements, which was supported by morphological microscopic evidence. For accuracy of starch profile measurements, the use of freshly cooked potato samples is essential.