By Whitney Crouch, RDN, CLT
Collagen: It’s the most abundant structural protein in the body, and it’s more than just a hip, new trend popularized by different lifestyle personalities and brands. It takes the shape of a triple helix composed of the continuous repetitive motif, Gly-X-Y, where Gly is glycine, X is proline (Pro), and Y is hydroxyproline (Hyp).1 The latter two amino acids are specific to collagen structures. These protein building blocks make up the structure in skin, tendons, bones, and teeth and are integral in the health and maintenance of these structures over our lifetime.
Collagen is found naturally in the connective tissue of land animals such as humans, cows, and chickens, as well as some marine life, including fish. It makes up about 25% of our bodies’ protein content and is helpful in soft-tissue repair.2-3
People who consume animal protein regularly in their diet are consuming some collagen; however, muscle-meat proteins largely lack the rich proteins found in connective tissue. Individuals who routinely sip traditionally prepared bone broth benefit from the collagen extracted from the cartilaginous tissue used in the broth’s preparation. Furthermore, studies show that easily digested and absorbed forms of collagen, like those found in quality dietary supplements, can have an even greater rate of absorption than traditionally prepared foods.
Different types of collagen
Whether from animal or marine sources, all collagen comes from amino acids, the building blocks of protein in the body. Animal and marine collagens are constitutionally the same—that is, they’re made up of the same amino acids—however, animal sources have a larger quantity of some amino acids (proline and hydroxyproline, specifically).4
Research shows there are more than 28 different types of collagen, but the three most abundant are Types I, II, and III. These collagen types form the structural fibrils of tissues, while the others take part in the association of these fibrils with other tissues.2
- Type I: This is the most abundant form of collagen and is found in tendons and throughout the body. It is a key building block for hair, skin, nail, blood vessel, and teeth health.5
- Type II: This type of collagen structure is found most often in joint cartilage.6
- Type III: This is the second most abundant form of collagen and is always found in association with Type I collagen.5
What is the difference among hydrolyzed collagen, collagen peptides, and gelatin?
- Gelatin is the denatured form of collagen, but it is packaged in a different structure from other forms of collagen. It’s created by partial hydrolysis (breaking apart) of the full-length protein, and depending on the extraction process used, gelatin may vary in functional properties, despite having the same amino acids content as collagen. Gelatin, also considered the cooked form of collagen, usually undergoes extensive processing which decreases its bioavailability.7 Gelatin mixes well with hot water and becomes a gummy solid when cooled.
- Hydrolyzed collagen (also called collagen hydrolysate) is the result of the enzymatic breakdown (or hydrolysis) of the full-length collagen protein, extracted and dehydrated (into a white powder). It contains a mixture of different types and combinations of collagen peptides. Because of its smaller size, hydrolyzed collagen is easier to digest and use. The absorption rate of hydrolyzed collagen is said to be over 90% compared to only 27% or less in food.1
- Collagen peptides (another name for hydrolyzed collagen and collagen hydrolysate) involve the breaking down of the molecular bonds between individual collagen strands to peptides. These are specific peptides fragments, usually 2 to 20 amino acid residues in length, which have biological activity. Due to their smaller size, these peptides show higher bioavailability and are better absorbed into the bloodstream.1 Collagen peptides mix well with hot or cold liquids, and these mixtures remain liquid when at room temperature and when cold.
In addition to improving structural integrity and elasticity of the skin, the consumption of Types I and III collagen also improves skin’s ability to retain moisture and may fight UVB photodamage, which in turn promotes healthier and younger looking skin, according to studies.8-10
There is also mounting clinical evidence of collagen’s benefits in strengthening the collagenous structures of hair and nails. A study in the Journal of Investigative Dermatology reveals that collagen is strongly deposited in hair follicles, and the lack of collagen delays hair cycling and growth, suggesting that collagen could be a potential area warranting further investigation.11
In a six-month study looking at brittle nails, researchers found that daily supplementation with collagen resulted in increased nail growth and improved brittle nails in conjunction with a notable decrease in the frequency of broken nails.12
Inner strength and resilience
Additional evidence shows that supplementing with oral collagen stimulates collagenic tissue regeneration by increasing not only collagen synthesis, but minor components (glycosaminoglycans and hyaluronic acid) synthesis, as well. One such study used validated self-perception questionnaires to measure joint comfort and overall joint health in study subjects. After 90 days of intervention, 78% of subjects in the test group reported to have less joint discomfort, and more than 60% of the subjects agreed their joint health improved by increasing joint flexibility, mobility, and reducing joint stiffness. There were no statistically significant changes in the control group.13
As if the benefits of adequate dietary collagen seen in hair, skin, nails, and joints aren’t enough, there is also evidence to support collagen and gelatin’s role in bone health. In bone, approximately 95% is Type I collagen, providing viscoelastic strength, torsional stiffness, and load-bearing capacity. Type II collagen is also involved in bone formation, even though it is mainly found in cartilage.14
While the body of evidence around collagen supplementation continues to grow, the benefits of daily supplementation with collagen peptides (hydrolyzed collagen) can already be seen. There are uses for both gelatin and collagen peptides in cooking, baking, smoothies, and other means; however, the higher rate of digestion and bioavailability of the peptide form makes this supplement a great addition to anyone’s health routine.
- Fu Y et al. Exploration of collagen recovered from animal by-products as a precursor of bioactive peptides: Successes and challenges. Crit Rev Food Sci and Nutr. 2018;2:1-17.
- Rodriguez MIA et al. Collagen: A review on its sources and potential cosmetic applications. J Cosmet Dermatol. 2018;17:20-26.
- Eastoe JE. The amino acid composition of mammalian collagen and gelatin. Biochem J. 1955; 61(4):589-600.
- Fazli S et al. Marine collagen: an emerging player in biomedical applications. J Food Sci Technol. 2015;52(8):4703–4707.
- Lodish H et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Section 22.3, Collagen: The Fibrous Proteins of the Matrix. https://www.ncbi.nlm.nih.gov/books/NBK21582/
- Buckley MR et al. Distributions of types I, II and III collagen by region in the human supraspinatus tendon. Connect tissue res. 2013;54(6): 374–379.
- Eastoe JE. The amino acid composition of mammalian collagen and gelatin. Biochem J 1955; 61(4):589-600.
- Shimizu J et al. Oral collagen-derived dipeptides, prolyl-hydroxyproline and hydroxyprolyl-glycine, ameliorate skin barrier dysfunction and alter gene expression profiles in the skin. Biochem Biophys Res Commun. 2015;456(2):626-30.
- Nozomi J et al. Optimization of dose of collagen hydrolysate to prevent UVB-irradiated skin damage. Biosci Biotechnol Biochem. 2016;80(2):356-9.
- Proksch E et al. Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study. Skin Pharmacol Physiol. 2014;27(1):47-55.
- Chen P et al. Lack of collagen VI promotes wound-induced hair growth. J Invest Dermatol. 2015;135(10):2358-2367.
- Hexsel D et al. Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails. J Cosmet Dermatol. 2017;16(4):520-526.
- Clark KL et al. 24-week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Curr Med Res Opin. 2008;24(5):1485-96.
- Czajka A et al. Daily oral supplementation with collagen peptides combined with vitamins and other bioactive compounds improves skin elasticity and has a beneficial effect on joint and general wellbeing. Nutr Res. 2018;57:97-108.