Glutamine is one of my favorite supplements, and for good reason. It plays a powerful role in gut healing, immune function, and cellular energy. In this article, we’ll take a deeper dive into what glutamine is, how it works in the body, its many benefits, who should consider supplementing, and when caution is advised.
What is Glutamine?
Glutamine is a conditionally essential amino acid, meaning that under normal circumstances, your body can produce enough on its own. However, during periods of stress, illness, intense exercise, or injury, the demand for glutamine exceeds the body’s ability to produce it.
It is the most abundant amino acid in the bloodstream and is found in both plant and animal proteins. It exists in two forms: L-glutamine (the form used in supplements) and D-glutamine (less biologically relevant for human metabolism).
Amino acids can be used by the body to produce proteins. There are 20 different amino acids that when put together in various sequences (determined by our DNA), different proteins are formed, such as hormones, enzymes, transporters, immunoglobulins, signalling molecules, and structural proteins like collagen and muscle proteins. The human body produces over 100,000 different proteins. Several amino acids can have functions outside of building proteins, and glutamine is one of them. Glutamine is basically all about healing tissues.
Glutamine serves multiple roles at the cellular level:
- Fuel for rapidly dividing cells: Cells of the intestinal lining (enterocytes) and immune cells (like lymphocytes and macrophages) use glutamine as a primary fuel source. This helps maintain the integrity of the gut lining and supports immune function.
- Precursor for nucleotide synthesis: Glutamine provides nitrogen for the synthesis of DNA and RNA. We need to make new DNA every time we make new cells. We need to make RNA every time any cells expresses genes and produces proteins.
- pH buffering: In the kidneys, glutamine helps maintain acid-base balance by donating ammonium ions (NH3) for the excretion of acid.
- Regulation of cell volume and antioxidant activity: It helps transport other amino acids into cells, regulates osmotic balance in cells, and contributes to glutathione production, one of the body’s most important antioxidants.
Here’s a quick breakdown of glutamine’s major functions:
- Repairs and maintains the intestinal barrier (great for leaky gut!)
- Supports immune health, especially during illness or stress
- Promotes muscle recovery and reduces soreness post-exercise
- Enhances wound healing, great supplement after any surgery
- Aids in detoxification via support for glutathione production
- Regulates acid-base balance in the kidneys
- Acts as a nitrogen shuttle to transport ammonia safely in the body
- Plays a role in brain health by converting to glutamate and GABA (calming neurotransmitter) as needed
Who Can Benefit From Glutamine?
Glutamine is especially helpful for individuals experiencing:
- Leaky gut syndrome – Many things can damage our gut on a regular basis including: processed foods, alcohol, toxins, EMF, pesticides, pain meds, infections, and chronic inflammation
- Inflammatory bowel conditions
- Food sensitivities and allergies
- Chronic stress or burnout (which depletes glutamine stores)
- Post-infection recovery (especially after GI infections)
- Post-surgery or injury recovery
- Heavy training or physical exertion
- Chemotherapy or radiation (shown to reduce mucositis and improve GI health)
- Autoimmune conditions with gut or immune involvement
All tissues go through stages of healing from injury/ damage to inflammation (acute short term inflammation ishealthy and beneficial), then proliferation where new cells are made, and thenremodeling where old cells are broken down and removed and new cells fill in. Depending on the extent of the damage and what type of tissue, some scaring can occur.
Who might not benefit from a glutamine supplement
Some people naturally make enough glutamine or get sufficient amounts through diet (from sources like meat, dairy, eggs, fish, cabbage (surprisingly high glutamine for a plant), nuts, and legumes). Individuals who may not need supplementation include:
- Those in overall good health with no signs of leaky gut, inflammation, or immune stress
- People eating a high-protein diet who are not under physical or mental stress
- People with heightened neurological sensitivity such as anxiety or seizures, or are on anti-seizure medication. Glutamine can be converted into glutamate (stimulatory neurotransmitter) and can increase neurological sensitivity
It is important to note the impact of glutamine on the nervous system. Glutamine can be used in the brain to produce either glutamic acid (stimulatory) or GABA (calming).
Functions of Glutamate
We need to have a balance of both of the neurotransmitters. Glutamate is required for thinking, learning, memory, motor control, and mental alertness. Too much glutamate will cause anxiety, feeling over-stimulated, insomnia, increased sensitivity to stimuli, and glutamate excitotoxicity can damage neurons and mitochondria.
Functions of GABA
GABA is what makes us feel relaxed, calm, emotionally stable and helps us sleep. It is also involved in calming motor movements so we are moving in a jerky twitchy way. As much as GABA sounds glorious to anyone with anxiety, too much GABA is also not good. Excess GABA will make you feel excessively tired, unmotivated, brain fog, low libido, drowsy and lazy.
It is important to understand that taking glutamine can impact the nervous system in either an excitatory OR inhibitory way depending on which pathway is favoured. And you can control this to a certain extent.
Conditions that favour the Glutamate pathway include: stress, danger, cortisol (stress hormone), low vitamin B6, high inflammation, high histamine, and fight-or-flight neurotransmitters.
Conditions that favour the GABA pathway include: Sufficient vitamin B6, relaxation, meditation, low cortisol, low adrenaline, omega 3 fatty acids, healthy gut microbiome organisms.
How to take L-glutamine
It is best to take 5g of glutamine powder mixed with water on an empty stomach, either first thing in the morning, at least 2 hours before eating, or at bedtime, at least 3 hours after last meal. For more damaged tissues, 5g can be taken twice per day. If glutamine is taken with food then the body will tend to use it for building proteins. To heal the gut, help the immune system, repair tissues, etc, it is best taken when no other food is present in the digestive system. You can consume tea or coffee with the glutamine.
