Collagen is no longer a topic exclusive to elite wellness circles. Whether you’re flipping through the latest issue of Cosmo, lifting heavy in the weight room, or leafing through pamphlets at your healthcare provider’s office, you’ll find it being discussed. 

So, what exactly is collagen? Quite literally, it’s the glue that holds our bodies together. It impacts everything from skin to ligaments to the gut (and right down to the cellular level), with different types of collagen supporting health in different ways.

A protein consisting of amino acids, collagen is so important that it makes up approximately 30 percent of all the proteins in the body. (You’ll find it in all bodily systems and organs.)

Keeping our collagen in good standing is crucial for our health in a number of ways. Without ample collagen, our skin, hair, tendons, ligaments, cartilage, and even the gut and gut lining can be affected. As a fervent advocate for the importance of gut health, here I’ll break down how collagen factors into a healthy gut.

How Gut Health Is Connected To Overall Health

In my opinion, gut health hasn’t received the attention it deserves. That’s why it’s imperative to first talk about gut health in relation to overall health.

I believe that Hippocrates, known as the Father of Medicine, had it right more than 2,000 years ago when he noted—and this is paraphrased—that all health begins in the gut. The connection between gut health (including the gut lining, which is comprised of nearly 100 percent collagen) and overall health cannot be overstated. 

Here are a few “gut facts” that might interest you:  

• Your gut is often referred to as your “second brain,” since it can influence your emotions, immune system, and overall health. 
• The gut also acts as its own “brain” because it doesn’t need impulses from the brain to implement the function of digestion. No other bodily organ (not even the heart!) can do that. 
• Your gut has more than 100 million nerve cells in it. There are more neurons found in the approximately nine meters of your intestines than in the spinal cord or the peripheral nervous system.  
• Your gut has its own nervous system, called the enteric nervous system, that controls the mechanisms of digestion and elimination. 
• The vagus nerve, which is responsible for various internal organ functions, is embedded in your gut. Its fibers carry information from the gut to the brain vs. the brain to the gut. In short, the brain interprets gut signals as emotions. 
• Approximately 95 percent of your body’s serotonin (the feel-good neurotransmitter) is found in the gut. 
• Between 70 percent to 80 percent of your entire immune system is housed in the gut and is referred to as the gut-associated lymphatic tissue, or GALT. 
• The lining of the intestinal wall has more immune cells than there are circulating throughout the body. Why? The intestinal wall lining is the border between you and the outside world and filters what to let in or keep out.
• The intestinal lining typically renews itself every three to four days and is critical to what does or doesn’t get absorbed by the body, including everything from nutrients, food, and toxins, to criticism, judgment, opinions, and even compliments. 

How Collagen Affects Gut Health

The human intestinal barrier, or gut lining, is permeable, allowing the absorption of “good guys” (think nutrients, electrolytes, and water) into the bloodstream while keeping out the “bad guys” (such as toxins). Keeping this normal barrier function healthy is more important than many people may realize.  

The crazy thing about this ever-important barrier: It’s just one cell layer thick. That’s approximately three to 10 nanometers. To put that in perspective, a sheet of paper is about 100,000 nanometers thick. So, we’re talking about thousands of times thinner than a piece of paper.

If the intestinal barrier is occasionally compromised by diet, stress, and other offenders, though, it doesn’t perform as well as it should. Part of this equation is that tightly bound epithelial cells (known as “tight junctions”) that seal up the intestinal barrier can be “unzipped” by a protein called zonulin, which then compromises the barrier’s integrity. We don’t have a complete understanding of what causes the body to produce zonulin, but gluten and harmful bacteria, as well as certain genetic factors or predispositions, seem to be involved.

Now, this is where collagen comes in. Collagen contains a unique amino acid profile, which multiple amino acids that benefit the gut lining, such as glutamine, glycine, and proline. Here’s some more about why these amino acids are so beneficial for gut health:

Glutamine, for one, plays a key role in many biological processes in the body, including the normal synthesis of protein and the maintenance of intestinal tissues in the body, offering gut support by promoting a healthy intestinal lining and function.

Glycine, meanwhile, is a small amino acid that has powerful bodily effects and is catalytic in various biochemical reactions, including the building of healthy DNA and RNA strands. These genetic building blocks are essential for properly functioning bodily cells—including those significant intestinal lining cells. 

Then there’s proline, which is necessary for proper bodily collagen formation, tissue repair, healthy arterial function, and more. It makes up approximately 15 percent of collagen and helps the body break down proteins to use in healthy cells, including (you guessed it) the cells of the intestinal lining. 

The Research On Collagen And Gut Health

We have plenty of evidence that intestinal barrier integrity is vital—and that a compromised gut lining contributes to everything from inflammatory bowel disease to obesity and metabolic disorders.

And though I’ve been aware of the gut benefits of collagen for some time now, various studies I’ve come across in my research back this up, too. Some suggest that the regular use of collagen peptide supplements can promote a healthy gut epithelial lining, including by enhancing those important tight junctions. In one study, for example, consumption of Alaskan pollock-derived collagen was found to help promote healthy tight junctions via a healthy gut epithelial barrier. 

So, not only do studies support the importance of maintaining a healthy gut lining for overall health, but point out how using collagen can promote the health of tight junctions, which, in turn, benefit a healthy intestinal barrier. 

Considering that our gut health is tied to our overall health, I believe that the consumption of collagen peptides is foundational for gut health and more. (I’ll also note that combining collagen with certain tight-junction-tightening probiotics—particularly soil-based organisms known as Bacillus coagulans—as well as collagen-production-promoting vitamin C is a great way to maximize the benefits, which is why these ingredients are both included in Ancient Nutrition’s Multi Collagen Protein.) 

How To Supplement With Collagen To Support Gut Health

Based on my research and clinical experience with patients, I believe that a good starting place for supplementing is 20 grams of hydrolyzed collagen peptides per day. Why hydrolyzed? The hydrolysis process results in small, intact amino acids that haven’t been damaged and help to form and support collagen in the body. When it comes to collagen, the size of the peptides and the method of processing have everything to do with collagen’s efficacy, activity, and benefits. Hydrolysis maximizes those.   

I also believe that consuming different types of collagen can be beneficial. The truth is, most collagens on the market offer one or two types—types I, II, and III—from either fish, beef, or chicken sources only. However, the body can likely benefit from multiple types of collagen, as at least 28 types of collagen have been identified in the body.

These are five of the main types:

• Type I, which makes up approximately 90 percent of the collagen in your body and provides structure to the skin, bones, tendons, and ligaments
• Type II, which is located in elastic cartilage and offers joint support
• Type III, which is located in muscles, arteries, and bodily organs
• Type IV, which is located in the skin’s layers
• Type V, which is located in the eyes’ corneas, some skin layers, in hair and placental tissue

The more collagen sources and types in a supplement, the better, since the body has so many types within it. That’s why Ancient Nutrition’s Multi Collagen Protein provides 10 collagen types from four real food sources: hydrolyzed bovine collagen peptides, chicken bone broth collagen concentrate, hydrolyzed fish collagen peptides, and a proprietary, clinically studied fermented eggshell membrane collagen.

Read More: 15 Signs That Something Is Off With Your Gut

No matter what brand of collagen you choose, collagen peptides are easy to use and incorporate into your diet. Choose an unflavored collagen powder and you can mix it into coffee, tea, smoothies, soups, sauces, and other favorite recipes. If your collagen is vanilla– or chocolate-flavored, it’ll be perfect for decadent smoothies, ice cream, puddings, “hot chocolate,” vanilla lattes, baked goods, and more.

As long as you’re consistent in taking your collagen daily, you can take it whenever works with your schedule and preference. Just how long it takes to experience the benefits of  a collagen routine depends on a few factors, including the specific product formula and your current state of health.

Dr. Josh Axe, D.N.M., D.C., C.N.S., is a doctor of natural medicine, clinical nutritionist, author, and co-founder of Ancient Nutrition. Dr. Axe operates one of the world’s largest natural health websites, sharing healthy recipes, herbal remedies, nutrition and fitness advice, and information on essential oils and natural supplements. Dr. Axe founded one of the largest functional medicine clinics in the world and has served as a physician for many professional athletes.