All About Collagen (Plus 8 Ways to Support A Healthy Gut)



Collagen is getting a lot of buzz lately because of its gut-healing properties. But just why is collagen so amazing? And should you be adding it to your diet?

How Does Collagen Work?

Collagen is a family of proteins that forms the matrix of our connective tissue: the framework that supports our body tissues and organs. Collagen is often referred to as the biological “glue” that holds our bodies together and in fact the word collagen derives from the Greek word for glue, due to its characteristic to turn from a hard, insoluble substance into a “soluble, gummy gelatin” when heated in liquid. What actually happens is that when heated in liquid, collagen becomes hydrolyzed, or bonded with water molecules to form gelatin.

These two forms of connective tissue are essentially the same despite a clear distinction for culinary uses: gelatin or gelatin powder dissolves in hot liquids and thickens or forms a gel compared to hydrolyzed collagen powder which is collagen that has been processed into very small, intact amino acids. Collagen powder dissolves in both hot and cold liquids and does not form a gel. (1)

In addition to framing our cells which keeps them organized,  collagen acts as a shock absorber, reduces friction, cushions joints, and helps tissues withstand both enormous stretching and load known as tensile strength.  Collagen makes up a third of the protein in our bodies.

There are at least 28 different types of collagen protein and they all consist of a triple helix of chains of repeating amino acid sequences. Found in 30 percent of fibers, glycine is the most abundant amino acid in collagen. It is followed by proline which comprises about 15 percent of fibers.

Although there are many different types of collagen, types I, II and III make up 80-90 percent of the total amount found in the human body.  (2)

What Are the Different Types of Collagen?


Type I is the most abundant collagen and is thick and strong or “organized.”  Type I collagen is concentrated in the following areas:

  • Skin
  • Scar tissue
  • Tendons
  • Ligaments
  • Blood vessels
  • Organs
  • Bone
  • Dentin
  • Interstitial tissues of the extracellular matrix (the “stuff” between our cells)

A strand of type I collagen is stronger than its counterpart made of steel! (3)

Type II collagen is the least organized form of collagen. It’s relatively soft and is the main component of cartilage primarily found in:

  • Joints
  • Ears
  • Noses

Type II collagen can also be dispersed as a gel.

Type III collagen is the second most abundant type. It is concentrated in:

  • Muscles
  • Blood vessels
  • Hollow organs (such as the uterus and intestinal walls)

Type III collagen is also interwoven with type I in skin and other connective tissues concentrated with type 1 collagen.

What Are The Symptoms of Collagen Deficiency?

The collagen in our connective tissues undergoes recycling as part of normal metabolism. However, there are circumstances that lead to excessive loss and weakening, such as:

  • Aging
  • Illness
  • Trauma
  • Nutrient deficiency

Without well maintained collagen, our health and our appearance will suffer.

Symptoms of too little collagen include:

  • Wrinkling and sagging skin
  • Inflammation
  • Joint damage
  • Joint pain
  • Bone loss
  • Muscle loss
  • Poor wound healing
  • Gut issues

What Are The Benefits of Collagen?


Collagen hydrolysate and gelatin are two supplements that are well absorbed from the gut and have been shown to improve signs of facial skin aging, promote healing of pressure ulcer wounds, increase bone mineral density, and increase muscle mass in the elderly. (4,5,6,7)

Gelatin supplementation has been shown to have gut healing properties. In one study, gelatin protected against ethanol-induced mucosal damages in rats. (8)

In another study published in the Journal of Clinical Gastroenterology, gelatin was a key component of a supplement mixture that had a very strong anti-inflammatory effect on human intestinal epithelial cells. The authors concluded that the gelatin mixture could be therapeutic for intestinal disorders such as inflammatory bowel conditions where inflammation plays a key role. (9)  

For arthritis, there is a large body of research for collagen’s therapeutic effects for joint swelling and joint pain in both diseased and healthy subjects.

In one randomized, double-blind trial involving 60 patients with severe, active rheumatoid arthritis, a decrease in the number of swollen joints and tender joints occurred in subjects fed type II collagen for three months but not in those that received a placebo. Four patients in the collagen group had complete remission of the disease only to have their symptoms return when they stopped taking collagen. (10)

In another randomized, double-blind, controlled trial, 250 subjects with osteoarthritis of the knee were given 10 grams of collagen hydrolysate daily for six months. The subjects saw significant improvement in knee joint comfort. (11)

Healthy subjects experiencing joint pain and limited mobility from strenuous exercise also benefit from collagen supplementation. In a double-blind, placebo-controlled study of 55 healthy subjects who had no prior history of arthritic disease or joint pain at rest but experienced limited joint mobility and discomfort with physical activity were randomized to receive a collagen supplement or a placebo for 120 days. Collagen supplementation led to improved knee joint extension and lengthened the period of pain free strenuous exertion. (12)

Bottom line: Collagen supplementation can be beneficial for:

  • Reducing impacts of aging
  • Wound healing
  • Increasing bone density
  • Increasing muscle mass
  • Healing the lining of the gut
  • Reducing inflammation
  • Easing arthritis pain
  • Reversing rheumatoid arthritis
  • Increasing mobility in osteoarthritis
  • Improving joint pain from exertion

The Benefits of Glycine and Proline

The therapeutic effects of collagen and gelatin are due in large part to the bioactivity of two amino acids that we have already mentioned: glycine and proline.

Although glycine and proline are categorized as non-essential amino acids because our bodies can make them from other amino acids, the amounts we make are limited. Proline is amply supplied in most diets, but glycine is found mainly in gelatinous cuts of meat, of which most people eat very little. In the case of glycine, the amount we synthesize does not make up for the lack in our diets.

We consume about two grams of glycine per day via diet and we make around 1.5 – 3 grams per day. It’s been determined that we need about 10 grams per day for basic health and even more if we are injured or sick. It seems that, at best, we are only covering half our glycine needs. Glycine then, is not really non-essential, but “semi-essential” or “conditionally-essential” because we only make a fraction of what’s required to support a healthy metabolism. (13)  

In certain instances, proline can be considered conditionally-essential as well. Although it’s abundant in foods that contain protein, our needs may not be met during periods of accelerated growth, catabolic illness, need for increased wound healing, or if following a low protein vegetarian or vegan diet. (14, 15)

Glycine has been shown to:

  • Play an essential role in the synthesis of DNA, RNA, and many other proteins.
  • Have anti-ulcer activity. (16)
  • Assist muscle growth and repair.
  • Play a role in the production of glutathione, an essential antioxidant found throughout the body that influences collagen synthesis. (17)
  • Regulate blood sugar levels by controlling gluconeogenesis (the process of turning non-carbohydrate substrate such as amino acids into glucose).
  • Improve sleep quality and reduce daytime fatigue and memory loss from insomnia.
  • Have an inhibitory effect on neurotransmitters that cause seizure activity and bipolar disorder. (18)
  • Act as a neurotransmitter that counteracts stress and anxiety by promoting feelings of calm. (19)
  • Aid in the recovery from joint damage and relief of joint pain.
  • Assist against inflammatory bowel disease.
  • Modify the immune response.
  • Negate the link between meat intake and diabetes.
  • Play a role in the release of glucagon-like peptide 1 which has been shown to increase satiety via control of gut hormones.
  • Assist stage II liver detoxification.
  • Neutralize homocysteine, a potentially toxic metabolite of methionine.

Proline is critical to the stability of collagen’s triple helix and without enough proline collagen literally falls apart.  Proline plays a particularly important role in skin, tendons, wound healing, cell metabolism, heart muscle and blood vessels. Proline also has a very potent antiatherosclerotic function in preventing the binding and retention of a hazardous lipoprotein called Lp(a) to arterial plaque. (20)

Lp(a) is a very atherogenic particle in your blood that carries cholesterol, fats, and proteins. How much Lp(a) you have is genetically determined and levels are not influenced by diet and exercise. Lp(a) is “sticky” and adheres to plaques in your arteries that create blockages causing heart attacks and strokes. In fact, researchers have determined that one in 14 heart attacks and one in seven cases of aortic valve disease are due to elevated Lp(a) levels. (21)

Proline essentially neutralizes Lp(a) by making it less sticky so it releases from plaques back into the bloodstream. This plaque reversal facilitates improved circulation and less risk of heart attack and stroke.   

How can we ensure that we’re supplying our bodies with adequate glycine, and proline for optimal health?  We can eat more connective tissue! It’s Paleo folks, so let’s up our intake of collagen and gelatin.

8 Ways to Support A Healthy Gut By Eating More Collagen


1. Eat tough cuts of meat that take a long time to cook to be chewable. Brisket, chuck roast, rump roast, ribs, oxtails, shoulder and necks.

2. Eat the skin. Whether it’s chicken skin, salmon skin, or pork rinds, skin is almost all collagen—eat it!

3. Eat the bones. The soft ends of chicken bones are loaded with collagen, as are all long and short bones that are soft enough to eat after extensive cooking, such as after making bone broth.

4. Use powdered gelatin. There are high quality brands out there such as Great Lakes Gelatin and Vital Proteins that obtain their gelatin from grass-fed animals. You can add powdered gelatin to any hot liquid that you want to gel or thicken such as soups or sauces. You can also make fun, tasty (and healthy) gummies, puddings, or “jello” desserts. Gelatin can even be used as an egg replacement. Just mix a tablespoon of powdered gelatin with three tablespoons of hot water for 1-2 eggs.

5. Use hydrolyzed collagen. Great Lakes Gelatin Collagen Hydrolysate and Vital Proteins Collagen Peptides dissolve in both hot and cold liquids so you can add it to anything from water to smoothies and just drink it right up.

6. Drink bone broth which is loaded with gelatin. You can buy pre-made bone broth or bone broth protein, which is dehydrated bone broth that you blend into liquids or add to meals, or you can make it yourself! When making your own, you’ll want your broth to gel when cooled because it’s a sign that you extracted a lot gelatin out of your bones. If the gel seems icky to you, don’t worry because it dissolves back into liquid as soon as you heat your broth back up. If your bone broth doesn’t gel, you can try:

  • Adding more connective tissue in with your bones: skin, tendons, extra meat, heads including fish heads, feet, knuckle bones, and wings with or without the meat and skin still attached.
  • Starting your bone broth out as a boil before lowering the heat to a simmer until done.
  • Adding a tablespoon or two of vinegar such as apple cider vinegar. The acid helps extract the collagen from your bones.
  • Cooking your broth for an extra long time. Poultry bones can simmer for up to 24 hours and beef bones can go as long as 48 hours!
  • Using a pressure cooker such as the Instant Pot. Pressure cooking greatly speeds up the time it takes to get a good gel going in your broth.

7. Snack on collagen bars such as Primal Kitchen Collagen Bars and Bulletproof Collagen Protein Bars. Both provide collagen from grass-fed animals.

8. Eat organ meats such as liver, heart, tongue, and kidneys which are all high in collagenous fibers.  

Nutrients That Support Collagen Production

There are 19 amino acids involved in collagen production, and other critical nutrients, but here we focus on two of the most essential: lysine and vitamin C.


While other amino acids are involved, lysine is particularly noteworthy. In addition to working alongside proline to neutralize Lp(a), lysine is unique in its ability to block enzymes which break down collagen.

If the body is deficient in lysine, collagen is less likely to withstand the effects of trauma, disease, and aging. Conversely, if the body has sufficient lysine, even when cells are producing a lot of collagen dissolving enzymes, lysine makes them ineffective which prevents collagen breakdown and perhaps even puts the brakes on the disease process.

Lysine is an essential amino acid which means we have to obtain it from food. Paleo sources of lysine include:

  • Red meat
  • Poultry
  • Pork
  • Cod
  • Sardines
  • Nuts
  • Nutritional yeast
  • Eggs

Before lysine can be incorporated into collagen it has to be hydroxylated to form hydroxylysine. Some proline is also hydroxylated to form hydroxyproline. The hydroxylated forms of these amino acids enables cross-linking of collagen fibers which is critical for the stabilization, strength, and durability of collagen.

Vitamin C


Vitamin C is critical to the hydroxylation of lysine and proline and if vitamin C is deficient in the diet, collagen can’t form cross linkages. Without vitamin C, new collagen simply cannot be produced and the skin will easily bruise, joint pain will be more noticeable, wounds won’t heal, and bleeding gums that manifest as scurvy may be present.

The RDA for vitamin C is 75 mg per day for adult women and 90 mg per day for adult men. If you are following a Paleo diet that contains plenty of fruits and vegetables, you’re getting way more vitamin C than the RDA. Good Paleo sources of vitamin C include:

  • Kiwi
  • Citrus fruit
  • Chili peppers
  • Bell peppers
  • Kale
  • Broccoli
  • Dark leafy greens
  • Strawberries

Vitamin C also increases the absorption of iron from our gut, another nutrient important for collagen synthesis. (22) Selenium, zinc, copper, manganese and omega-3 fatty acids also play important roles in the formation and maintenance of collagen. (23)

Collagen for Total Body Health

When our Paleolithic ancestors ate an animal, they ate the whole animal, from nose to tail. In doing so, they ate way more collagen than we do today. Additionally, by eating the whole animal, they ate organs that supplied a plethora of vitamins and minerals lacking in our modern diets. Those nutrients supported optimal health, including the health of connective tissue. Traditional cooking methods—the stews and broths our more recent ancestors ate regularly—ensured the consumption of plenty of gelatin.

If you’re eating a well balanced Paleo diet full of nutrient dense, collagenous meats and organs and a variety of veggies, fruit, nuts, seeds, healthy fats, and oils, and you’re supplementing with collagen or gelatin powder during times when eating nose to tail just isn’t an option, it’s a good bet you’re getting plenty of nutrients to support optimal collagen production for healthy connective tissue.

10 Collagen Recipes

Want to cook your way into eating more collagen? Try these collagen-rich recipes.

New England Chuck Roast

Slow Cooker Garlic Chicken Drumsticks

Old Fashioned Slow Cooker Stew

Paleo Beef Stew

Slow Cooker Maple Bacon Chicken Legs

Simple Bone Broth

Fall Flavors Smoothie

Paleo Strawberry and Collagen Smoothie

Mediterranean Beef and Liver Burgers with Wilted Arugula

Juicy Skirt Steak with Chimichurri Sauce