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Commentary on Collagen
by Christina Badaracco, MPH, RD
In keeping with a growing interest in many different types of supplements, the demand for collagen supplements has accelerated in recent years. By 2030, the market is expected to reach $19.9 billion — which is slightly larger than the current market for fiber supplements. Purported to improve hair, skin and nails, collagen is often sought for cosmetic purposes, but it plays many different essential roles in the body. Can our bodies get enough collagen through our diet, or are supplements necessary? And even if supplements aren't harmful, are they actually helping to achieve the desired outcome?
What is collagen, and what are its roles in the body?
Collagen is the most abundant protein in the human body, comprising roughly one-third of all proteins in our bodies. Like all proteins, it consists of chains of amino acids known as polypeptides. These chains make up collagen molecules, which are bundled together into collagen fibrils, which, in turn, are bundled together into collagen fibers. Collagen fibrils exhibit a banding pattern that reflects repeated segments across the fibril's length.
Collagen is the primary building block of the skin, muscles, bones, tendons, ligaments and other connective tissues. It is also found in various organs, blood vessels and the intestinal lining. Its fiber-like structure is used to make connective tissue that helps maintain strength and resilience in the body's various tissues. More specific roles of collagen include:
Helping to replace dead skin cells
Providing a protective covering for organs
Imparting structure, strength and elasticity to the skin
Promoting blood clotting
There are 28 known types of collagen — with type I comprising over 90% of the collagen in the body. The most common types are shown below. These groupings generally reflect the kinds of structures they form in the body.
Each collagen type has a specific structure, function and manner of assembly with other collagen types. For example, one type is involved in cartilage calcification (or converting cartilage into bone), another supports adhesion between layers of the skin and another helps transmit signals between neurons. Several types of collagen comprise each fibril, and they collectively impart the structure and function that the fibrils need.
How do our bodies produce collagen?
Collagen can be endogenous, meaning that our bodies produce it, or exogenous, meaning that we consume it from external sources. When our bodies make collagen, they rely on various nutrients to form collagen by combining amino acids, which we obtain through food (or from available amino acids in the body) and serve as building blocks of new proteins. The body needs several key nutrients to produce collagen, listed in the table below.
As we age, existing collagen breaks down, and the body's production of new collagen becomes less efficient. Other environmental and lifestyle factors — such as excessive sun exposure, smoking, excessive alcohol and lack of sleep and exercise — can also impair collagen production. Reducing exposure to these stressors and eating an antioxidant-rich diet is essential to prevent damage. It may also be important to take proactive steps, like increasing exogenous intake through food or supplements, to support the body in producing even more collagen as it ages to ensure we have enough.
Some health conditions can inhibit production. Genetic disorders such as Ehlers-Danlos syndrome (EDS) and osteogenesis imperfecta (OI) can impair our collagen production; they can weaken our connective tissue (EDS) or bones (OI). Also, autoimmune diseases (when the body's immune system attacks its own tissue) such as rheumatoid arthritis, lupus and scleroderma can cause collagen damage. It may be advisable for people with these conditions to increase intake as well.
Where do we obtain collagen in the diet?
We can consume fully formed collagen through various animal sources in our diet, such as:
Fish bones and skin
Cuts of meat with connective tissue
However, many populations around the world eat fewer of these substances now that modern diets consist of more ultra-processed food. Even the whole meat and fish we eat are commonly pre-trimmed and wrapped in plastic at the grocery store, leaving behind little of the collagen-rich parts of the animal for us to consume. So, if you do eat meat, consider occasionally purchasing and consuming bone-in cuts of meat rather than pre-processed and packaged cuts or products. Consuming bone broth (ideally by making it with leftover bones at home) and fish with bones can also be good sources of collagen.
When should people consider taking supplements of collagen?
The growing evidence base indicates that specific collagen supplement dosages may benefit certain populations. Most studies have focused on joint and skin health. A few examples of studies assessing the effects of collagen supplements on the body include:
A 2014 randomized clinical trial with 69 patients showed that supplementation of specific collagen peptides improved skin elasticity among women
A 2019 randomized clinical trial with 128 patients showed that supplementation of collagen derived from chicken cartilage significantly reduced facial lines and wrinkles and crow's feet lines and wrinkles, increased skin elasticity and collagen in the skin, promoted a more youthful skin appearance and reduced skin dryness and erythema (or reddening of the skin)
A 2021 systematic review concluded that collagen supplementation can improve joint functionality and reduce joint pain
Notably, many of these studies contain fewer than 100 patients, which may limit the ability to generalize the findings. Also, most studies don't present results beyond one month after the intervention, so it's impossible to conclude that benefits will be maintained after supplementation ceases.
What types of collagen supplements are best to take?
Collagen supplements are typically taken orally and include hydrolyzed collagen, meaning the proteins have been broken down into their component peptides. Though collagen first became popular for use in topical applications in serums and creams, experts realized these media were ineffective because the applied collagen didn't reach the deeper layers of skin where it exists in our bodies; the fibers are too large to permeate the skin's outer layers.
Supplements may be found in capsule, liquid, gummy or powder form. Because all are derived from animal sources, no true "vegan" version exists. As long as they contain the same main ingredients, there isn't likely a meaningful difference between the different forms of supplements in their effect on the body. The recommended dosage varies depending on the form, with larger doses typically recommended for powders. They may also contain other components that promote collagen formation, such as vitamin C and hyaluronic acid (a molecule that binds to many water molecules to increase hydration). Generally, studies have indicated that adults can safely consume between 2.5 to 15 grams of collagen per day.
Overall, there is little evidence to suggest adverse effects can result from taking collagen supplements; however, they can be expensive, and it's not definitive that the peptides produced when collagen is digested will be directed to a specific area of the body to realize a desired outcome (or, as mentioned above, that changes will be permanent). Therefore, buying a high-quality supplement (often identifiable by third-party verification) with the right ingredients to meet your needs is important to avoid wasting money and maximize the potential benefit.
How can I best maintain my body's stores of collagen?
You can follow various lifestyle practices to maximize your body's production of collagen, including:
Prioritize getting adequate, high-quality sleep every night
Avoid smoking or exposure to secondhand smoke
Limit the amount of time spent in direct sunlight during peak hours and wear sunscreen when outside or exposed to light through a window
If you consume animal foods, choose cuts/pieces (at least periodically) that include connective tissue. Also, save and use bones from meat and fish to make a stock that will extract collagen and convert it into an edible format
If you choose to take supplements, keep in mind that the US Food and Drug Administration doesn't regulate collagen supplements, so the efficacy and contents may not be exactly what the label shows. Choose brands that have received verification from third-party organizations like United States Pharmacopeia and read reviews from ConsumerLab or Consumer Reports about products that have been independently tested.
Also, consider talking with your primary care doctor and/or registered dietitian to help ensure you choose the form and dosage of collagen that may be most effective to meet your needs.
Please view the resource materials here.
Christina Badaracco, MPH, RD
Christina is a registered dietitian and author who aims to improve access to healthy and sustainable food and educate Americans about the connections between food and health. She loves to experiment with healthy recipes in the kitchen and share her creations to inspire others to cook.
Christina completed her dietetic internship at Massachusetts General Hospital and earned her Master of Public Health degree from the University of California, Berkeley. Previously, she graduated with a degree in Ecology and Evolutionary Biology from Princeton University, after conducting her thesis on sustainable agriculture and energy in Kenya. She has done clinical nutrition research at the National Institutes of Health, menu planning and nutrition education at the Oakland Unified School District and communications at the Environmental Protection Agency's Office of Water. She has also enjoyed contributing to children’s gardens, farmers markets and a number of organic farms.