What is L-glutamine and what are its benefits?

What is glutamine?

Glutamine is the most abundant amino acid in our body, which supports many body functions and helps maintain overall health.

In fact, in situations of intense stress, e.g. after intense exercise, injury or surgery, glutamine needs are higher and its levels in the body decrease.

Which foods contain Glutamine?

L-glutamine is an amino acid that we can get from various foods – especially those rich in protein – of both animal and plant origin.

Many of the foods that contain it in large quantities are part of the daily diet of most people, while according to research it is estimated that approximately 3-6 grams of glutamine are consumed daily, exclusively through our diet.

The most typical foods that contain glutamine are the following:

1. Meat (beef, pork, chicken, turkey, venison)
2. Fish (eg cod, salmon)
3. Dairy products (cottage cheese, ricotta, mozzarella, milk, yogurt)
4. Legumes (lentils, beans)
5. Eggs
6. Tofu
7. Vegetables (asparagus, spinach, parsley, cabbage, broccoli, etc.)
8. Seeds (e.g. pumpkin seeds, sunflower seeds)
9. Nuts and nut butters
10. Whole grains (eg oats)
11. Corn
12. Spirulina

Low levels of glutamine rarely occur in humans and are usually related to either too little consumption of protein foods on a daily basis or to increased needs for the amino acid due to conditions such as:

• Intense exercise (e.g. frequent and demanding workouts)
• Intense stress
• Chronic gastrointestinal disorders
• Immune system disorders
• Certains medications
• Undergoing treatment (eg chemotherapy, radiotherapy)
• Current pathological conditions (e.g. infections)

Health benefits

Glutamine is important for removing excess ammonia from the body, while supporting the immune system and it is also important for brain & digestive health.

Furthermore, it reduces insulin resistance associated with stress, enhances the action of the antioxidant glutathione and contributes to the production of the proteins necessary for muscle tissue.

1. Gut health

One of the most studied & proven actions of glutamine concerns the support of gut health.

In particular, L-glutamine is an energy substrate for the small intestine and protects against atrophy of the intestinal mucosa, thus improving the immune function of the intestine.

It strengthens the intestinal barrier, thereby reducing intestinal permeability and supporting digestive function and nutrient absorption, while studies have shown it to help treat leaky gut.

In fact, taking it has been shown to help with various gastrointestinal diseases, e.g. Inflammatory Bowel Disease, with the main ones listed below:

• Irritable Bowel Syndrome (IBS)
• Crohn’s disease
• Ulcerative colitis
• Celiac disease
• Indigestion
• Leaky Gut Syndrome
• Diverticulosis
• Ulcers

Studies have also shown that it can reduce symptoms of irritable bowel, alongside a diet low in FODMAPs. In addition, it has been shown that people with ulcerative colitis and Crohn’s disease have low levels of glutamine in their bodies.

2. Immune system support

Glutamine is the main source of energy for our body’s lymphocytes, which are white blood cells that help fight infection and disease.

In fact, in certain health conditions (e.g. catabolic diseases) the body’s needs for glutamine increase dramatically, with the amino acid playing an important role in maintaining health and in the recovery of the body.

Although there is no total agreement on whether glutamine supplementation enhances immune function, it has been shown to reduce recovery time and hospital stay, health complications, and mortality rates in patients.

3. Brain function support

In addition to the benefit it offers to gut health and immunity, another proven effect concerns brain function. This is mainly related to the role of glutamine as a precursor of some important neurotransmitters.

Specifically, inside the brain it can be converted into glutamic acid, another amino acid that supports healthy brain function. It also increases levels of γ-aminobutyric acid (GABA), an amino acid that acts as a neurotransmitter in the body.

In addition, glutamine is an important source of energy for the nervous system. When the brain does not receive enough glucose, it increases the metabolism of glutamine for energy production.

It is worth noting that L-glutamine supplements are also likely to help in conditions such as dementia and various psychiatric disorders (depression, schizophrenia, etc.).

4. Glutamine and weight loss

Numerous studies have shown that L-glutamine supplementation helps reduce body weight – especially around the waist – and protect against metabolic disease, supporting cardiovascular and overall health.

Regarding the above, the ability of L-glutamine to modify the intestinal microflora, especially in overweight and obese people, as well as the antioxidant and anti-inflammatory properties of the amino acid, plays an important role.

From all the available evidence, it appears that L-glutamine supplementation improves body composition – decreasing fat and increasing muscle mass – and reduces the risk of:

• Hypertension
• Hyperlipidemia
• Type II diabetes
• Glucose intolerance
• Obesity
• Sports performance enhancement

Glutamine is essential for maintaining muscle protein. It prevents muscle catabolism, while enhancing the action of other amino acids, such as arginine and ornithine.

It is an amino acid widely used by athletes and it is recommended by many to be taken before and/or after exercise to improve athletic performance, speed muscle recovery, reduce fatigue, boost immunity and improve body composition.

While there is no consensus on whether it improves athletic performance, it may help boost the immune system – especially after overtraining. In addition, it has a regulatory effect on the muscles and prevents the excess of lactic acid resulting from intense anaerobic exercise, and by extension muscle fatigue and general tiredness.

5. Wound healing

When our body is under intense stress, such as after injuries, burns or surgery, there is a large decrease in glutamine levels.

Studies have shown that its administration strengthens the immune system and significantly increases the rate of wound healing (e.g. burns), while its intake by critically ill patients is associated with shorter hospital stays.

In what forms do we find it?

There are many glutamine dietary supplements, which vary in both content and form. Primarily, these supplements are available in the following forms:

• Powder
• Capsule
• Tablet
• Oral solution

The most common dosage in which L-glutamine is found is 500 mg per capsule/tablet.

The amino acid is either the sole active ingredient of a supplement, or a part of various sports preparations (e.g. protein powder) or some specialized formulas that promote health (immune system support, intestinal health, brain function).

What is the best glutamine?

This question cannot be easily answered as this is a matter of personal preference or need.

Athletes and sports people often take glutamine preparations post-workout, and usually prefer powdered glutamine to mix with a sports drink that may also contain other ingredients (eg BCAAs).

Some typical combinations of the amino acid with other active ingredients are as follows:

• Protein with glutamine
• Glutamine and BCAAs (Branched Chain Amino Acids)
• Glutamine with creatine and taurine
• Glutamine and Vitamin B1 (thiamine)
• Glutamine and Glutathione (antioxidant)
• Glutamine and Chios Mastiha (eg Natural Doctor L-Glutamine Chios Mastiha)
• Glutamine with vitamins, minerals and trace elements

On the other hand, people taking it for immune or gut health support seem to prefer taking it in capsule or tablet form.

When is the best time to take glutamine?

Amino acids are generally recommended to be taken on an empty stomach. In the case of glutamine, it is recommended to take it between meals – at whatever time of day suits everyone best – and/or before going to bed at night.

Many people wonder when is the best time to take glutamine, but there is no specific recommendation beyond the general guidelines mentioned above. The important thing is to strictly follow the instructions for use in each food supplement.

After all, glutamine is often part of a multi-ingredient formula, so recommendations may vary to support the best possible outcome. In general, it is best to avoid taking it immediately after a meal or snack, unless you are instructed to do so.

Finally, it is worth mentioning that glutamine should be kept at room temperature and in a dry environment, while it should not be taken with hot drinks or hot meals.

What is the usual dosage?

The dosage depends on each person’s health condition and the need for which they are taking it. So it can vary quite a bit from case to case.

In general, it is recommended to gradually increase the amount taken, so that the body can easily adapt to the supplement, while taking very high doses should only be done under the supervision of a doctor.

It is considered very safe to start with a dose ranging between 500mg and 2g per day. Then, a common dose is 2-5 grams of glutamine twice daily for a healthy (average) adult, with about twice that amount recommended for people who exercise frequently and intensely (e.g. athletes).

Another way of calculating the daily dose is as follows: 50 mg of L-glutamine per kg of body weight.

However, it is important to note that glutamine is also likely to be found in other dietary supplements (eg protein powders, multivitamins, gut health formulas, etc.). In this case, this quantity should also be taken into account.

The majority of clinical trials studying the potential benefits of the amino acid typically administer doses of 5-45 gr daily for up to 6 weeks, with no side effects usually observed.

Finally, it is worth emphasizing that taking vitamins of the B complex and, especially, vitamin B12 is also recommended for people who take large doses of glutamine for a prolonged period of time.

Does it cause any side effects?

Glutamine supplementation is generally considered safe and, in most cases, appears to cause no side effects even in relatively large doses (50-60 gr) taken over several weeks.

According to a number of studies where its intake was studied, doses ranging from 5-45 gr were safe and well tolerated by humans, without causing side effects, especially if not taken for a very long time.

Among the side effects that are likely to occur – more commonly after taking large doses of L-glutamine – are the following:

• Changes in bowel motility
• Dizziness
• Nausea and/or vomiting
• Itching
• Skin rash
• Cough
• Palpitation
• Pain (eg in the lower back)
• Haematuria (blood in urine)
• Change in skin color

In addition, L-glutamine can increase the effect of certain medications, and should not be taken at the same time as lactulose as well as with epilepsy treatments.

Glutamine and liver health

It is worth mentioning that taking glutamine can affect the liver and, in particular, some studies support that high levels of glutamine in the blood are likely to cause liver damage (e.g. liver failure). However, further research is needed to determine whether glutamine supplementation is potentially hepatotoxic.

Contraindications

Its additional intake is contraindicated in certain cases – unless instructed so by a doctor – with the following examples being the most typical:

• People with kidney or liver disease
• Psychiatric disorders
• Hepatic encephalopathy
• Seizures
• Reye’s syndrome
• Cancer patients
• Pregnant and breastfeeding women
• Children under 12 years old

Summary

Glutamine is a valuable amino acid that has multiple roles in the body. Therefore, one could say that it supports our overall health.

By combining a healthy lifestyle (balanced diet, regular exercise, stress management) with an appropriate amount of L-glutamine, it is very likely that you will see a significant improvement in your physical & mental state!

Find at Vita4you.gr a great varirty in Glutamine supplements!