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L-Glutamine for Gut Health: What You Should Know

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As gut health dietitians, we hear a lot of chatter about supplements for gut health like collagen or apple cider vinegar. In particular, we’re seeing an increasing interest in L-glutamine supplements for gut health. More specifically, there are some pretty big claims about its effectiveness in “healing the gut.”  What’s the scoop on L-glutamine? Does it actually help with your gut health? Should we all be taking it? 

What is L-glutamine?

Let’s start from the beginning. L-glutamine is an amino acid, which are building blocks for proteins. The human body uses 20 different amino acids to make many different types of proteins we use for things like cell repair, enzyme production, hormone regulation, and more. Amino acids we cannot make ourselves are referred to as essential amino acids. A good way to remember this is that ‘they are essential amino acids, so it is essential we eat them.’ On the flip side, non-essential amino acids can be made by the body when they are in short supply. We can still find these in food, but it isn’t as critical for us to eat them.

White L-glutamine capsules sit on top of a spoon and scattered on a yellow background

Glutamine is a conditionally non-essential amino acid. When we are healthy, our body makes all the glutamine we need. In fact, glutamine is the most abundant amino acid in our body and can be converted into other amino acids if needed.1 It is a real multitasker! However, if we are very sick or in a state of extreme inflammation, our body cannot make enough. In conditions like these, people often need some extra glutamine.

What’s the difference between L-glutamine and glutamine? The ‘L’ in L-glutamine refers to the physical orientation of the molecule. If you’re a science nerd like me, this is what is referred to as stereochemistry. Contrary to some thoughts on Tik Tok, the ‘L’ does not mean it only works on the left side of the body. The glutamine in your body and in supplements is both L-glutamine, whether it says it or not. For the sake of this post, I’ll be referring to both as ‘glutamine’. 

What does glutamine do in the body? 

Glutamine is thought to have many different roles in the human body. Glutamine is used for energy by the mucus layer in our intestine, by white blood cells, and in our kidneys. It’s also thought to be an important source of energy for our intestinal cells and good for our gut microbiome. 

And this is where the social media buzz begins. There are many claims on Instagram and Tik Tok about glutamine, including:

  • Cure bloating (it’s magic!)
  • Heal your gut (it’s revived!)
  • Fix leaky gut (it’s patched up!)

Is this true? Are we missing out on something big?! Let’s explore!

There is some research to show glutamine helps the health of intestinal cells (put strong emphasis on the word ‘some’). The sticky point is that we have to be careful with how we apply this to humans. Most of these studies are done in animal cells in a petri dish (in vitro). Studies like this are an important place for research to start but can’t easily be applied to real life.

Some of the studies done on humans have looked at how glutamine helps people recover from very serious health conditions. Namely, inflammatory bowel disease, sepsis, cancers, or severe burns.2 So far, these studies show the benefits of glutamine, such as fewer inflammatory markers and reducing intestinal permeability.3 As I mentioned before, extreme states of inflammation like these mean the body cannot make enough glutamine. So, the potential benefits found from supplementation make sense.

Glutamine for IBS: Is it Helpful?

How does glutamine help with irritable bowel syndrome (IBS) and other functional digestive disorders? Great question; no one seems to know yet (despite what the internet might tell you) Some studies show a benefit, and some don’t. For example, let’s look at two opposing findings:

  1. One study tested three different amounts of glutamine supplementation on healthy males. They found that the higher the dose the participants received, the more gastrointestinal discomfort they experienced.4
  2. On the flip side, another study showed that IBS participants on a low FODMAP diet and glutamine had less severe GI symptoms than participants on a low FODMAP diet and a placebo supplement.5

Basically, this area needs to be studied a lot more before we can give a stamp of approval for glutamine and IBS. We’d like to see some more studies done on humans before we recommend this to a human (like you). There isn’t any research that says glutamine supplements are unsafe, but this may not be the ‘big fix’ people claim it to be.

In Summary

If you’ve been considering taking L-glutamine for gut health, here are some takeaways for you:

  • An alternative to buying a glutamine supplement is to eat foods rich in glutamine. Since glutamine is a part of protein, we can find it in many protein foods. Think eggs, milk, meats, and fish. If you choose more of a plant-based diet, you can also get glutamine from beans and nuts.
  • If you are already taking a glutamine supplement or would like to try one, there doesn’t appear to be harm in doing so. Extra amino acids in our body are broken down and removed from the body in our urine. If your body thinks you are getting too much glutamine from your diet, internal production, and/or a supplement, you’ll just pee it out. That being said, if you take a supplement and start feeling unwell, make sure to stop taking it.
  • If you still have some questions about how glutamine or other supplements may impact your gut health, it’s highly recommended to speak with a registered dietitian. Our dietitians would love to chat with you and are highly specialized in giving personalized advice for digestive health
White L-glutamine capsules sit on top of a spoon and scattered on a yellow background
What is L-glutamine?

L-glutamine is a non-essential amino acid, meaning it can be made in the body. It is the most abundant amino acid in the human body. Typically, the body can make all the glutamine we need, but can also be depleted in cases of extreme inflammation and serious illness. Learn more.

What is the difference between glutamine and L-glutamine?

The ‘L’ in L-glutamine refers to the physical orientation of the molecule. The glutamine in the human body and in supplements is both L-glutamine, whether it specifically says it or not. Learn about the benefits of glutamine here.

What foods have glutamine?

Since glutamine is a part of protein, we can get it from eating protein-dense foods like meat, poultry, eggs, fish, and dairy. Some plant-based sources of protein include nuts, seeds, and legumes. More about glutamine for gut health.

Categorized: Gut Health & IBS

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    1. The role of glutamine in supporting gut health and neuropsychiatric factors. (2021). Deters & Saleem. Food Science and Human Wellness, 10(2), 149-154.
    2. When is it appropriate to use glutamine in critical illness? (2016). Mundi, M.S., Shah, M., & Hurt, R.T. Nutrition in Clinical Practice, 31(4); 445-450.
    3. The roles of glutamine in the intestine and its implications in intestinal diseases. (2017). Kim & Kim. Int J Mol Sci, 18(5): 1051.
    4. Gastrointestinal tolerance of low, medium and high dose acute oral L-glutamine supplementation in healthy adults: a pilot study. (2020). Ogden et al. Nutrients, 12(10), 2953.
    5. Glutamine supplementation enhances the effects of a low FODMAP diet in irritable bowel syndrome management. (2021). Rastgoo et al. Front Nutr, 8:746703.