L-Glutamine

L-glutamine is an amino acid that can increase your levels of growth hormone, it repairs damaged muscles, and it can also heal your gut – helping you to feel healthier inside and out.

L-glutamine is one of the most abundant amino acids in the human body. It helps to create new muscle fibres, repairs and heals your gut lining, and it can even regulate your hormones.

Furthermore, l-glutamine has also been shown to have a mild antidepressant quality, assisting the brain in repairing itself after stress or surgery. In addition to this, l-glutamine can be used to reduce oxidative stress; such as the type of stress we feel after intense exercise or illness.

L-glutamine is made in the intestines, brain, liver, and kidneys. The majority is created in the skeletal muscles – up to 60% in total. You can obtain l-glutamine from supplements and food sources, such as chicken, dairy, and tofu. The recommended doses of glutamine are 2-5 grams daily, but serious athletes should consider up to 10-40 grams daily.

When stress is put on the body; whether that’s from exercise, lifestyle (bad eating habits etc) or from medication; which may disrupt your gut lining, glutamine works to protect the intestines. This helps you to recover and heal your body from the inside out. (I) That’s because our health starts in the gut.

You may have heard that your gut is your second brain, and it couldn’t be truer. If you experience frequent colds, illnesses, or even depression, it could be due to an imbalance of your gut bacteria – which glutamine helps to heal and restore. Let’s have a look at how l-glutamine can achieve all of these amazing benefits.

Table of Contents

Functions and Benefits of L-Glutamine

L-Glutamine is used for a number of functions in the body. When you consider that most of the glutamine made or consumed is sent to your muscles, it makes sense then, that performance can be directly affected.

However, it’s not only sports performance where l-glutamine can help. It also heals and protects the body from the inside out. This essential amino acid provides a healing benefit throughout our entire body. Here’s a list of the most common ways l-glutamine can assist your body and mind:

Fights depression:

Researchers suggest that neuronal deficiency of l-glutamine can cause the onset of depression. L-glutamine assists the brain in normal everyday functions. Such as the transportation of essential nutrients to form new brain cells.

L-glutamine is a precursor to the neurotransmitter glutamate in the brain. The process that cycles glutamine and glutamate in the brain requires large amounts of energy. Research estimates that Gln/Gly(GABA) cycle accounts for more than 80% of cerebral glucose consumption. This makes L-glutamine an important component to consider where brain optimization (mental performance) is concerned.

The GABA cycle is an important process that can prevent the onset of epilepsy, bipolar disorder, schizophrenia, anxiety, depression, and alcohol addiction to name a few.

Study on mood and mobility:

One Korean study measured Glutamate and Glutamine concentrations in the prefrontal cortex of mice infused with an astrocyte toxin. The astrocyte toxin regulated the release of glutamine, thus lowering their concentrations. (II)

The study was to determine the outcome of mobility and the connection glutamine has on mood, more so, states of depression. The results showed that glutamate and glutamine levels decreased after 5 days.

Because of their glutamine decrease, the mice experienced immobility and a decreased preference for sucrose (sugar). This, according to the researcher’s theory, was an indication of depression and a lack of bodily functions below optimal. Here’s the interesting part;

Once the mice were directly infused with l-glutamine, the mice returned back to normal levels of mobility and normal system functioning. Meaning, their mood and mobility improved.

Controls blood sugar and weight loss:

Weight loss is another benefit to l-glutamine. By controlling blood sugar levels, it’s much easier to lose weight. It’s the spike in insulin that’s partly responsible for weight gain.

After six weeks of supplementation with l-glutamine at 30g per day, improvements were seen in cardiovascular risk factor patients. Along with body composition improvements in people with type II diabetes. (III)

Repairs damaged muscles:

L-glutamine supplementation is linked to athletics and bodybuilding for its positive effects on increasing human growth hormone, and muscle recovery. The glutamine/glutamate cycle that we’ve previously mentioned is also linked to protein synthesis – which is a precursor to building muscle.

The regulation of this amino acid, which takes place in your kidneys, gives oxidative fuel to your intestines and immune system cells. In summary; L-glutamine provides nitrogen transport between organs. This acts as a precursor for neurotransmitter synthesis, and glutathione production, and glucose metabolism.

Increases Human Growth Hormone:

Human Growth hormone HGH is a key hormone when you’re looking to building muscle. Growth hormone is also responsible for making you look younger, it fights diseases, and it also assists in the metabolism of fat for energy. Ultimately, helping you lose weight and reduce the signs of ageing. (IV)

A single dose of l-glutamine has been shown to improve HGH by up to 78%. (V) In one study, subjects were given two grams of glutamine to determine the effects it had on their plasma bicarbonate concentration, circulating plasma, and growth hormone concentration. The results? All levels elevated after only 90 minutes post-supplementation. (VI)

Protects the gut:

Most people might know glutamine as an assistant in gut health. Research suggests that l-glutamine plays a critical role in healthy digestion. Glutamine has been shown to protect against mucosal breakdown in the gut. This is important as it helps to breakdown the foods we eat to be turned into energy. (VII)

Any imbalances you have in your gut, increase the chances of your body not being able to fight off infections or absorbing vital nutrients from foods. If you’re someone who exercises regularly, where you’re putting your body under regular oxidative stress, then you might want to consider using l-glutamine as a ‘gut health’ supplement. A healthy gut means a healthy body, and mind!

Types of L-Glutamine

There are two forms of l-glutamine. There is regular l-glutamine, which is known as ‘free form’. To get the most out of this ‘free form’ glutamine, ideally, you should take it with food to help improve absorption rates. The second type of l-glutamine is called Trans-Alanyl-Glutamine (TAG) or Alanyl-L-Glutamine.

This type of glutamine is an amino acid attached to another amino acid. This form of the amino acid is known to be absorbed much better in the body. The difference between ‘free form’ glutamine and TAG, is that TAG is better absorbed, allowing you to take it without food on an empty stomach.

How to take L-Glutamine

As we’ve just discussed, it’s best to take the ‘free form’ with food, and Trans-Alanyl-Glutamine (TAG) on an empty stomach. However, to get the most out of glutamine in general, it’s best taken before, or right after exercise to see the best results. This will help your body replenish lost glutamine levels quicker. Furthermore, it will also assist in the absorption of nutrients from the foods you eat to heal your body pre, and post-exercise.

How Is L-Glutamine Made

L-glutamine is made in the kidneys and liver, but it can also be found in supplementation form and in a number of food groups.

L-glutamine in food:

Eggs: 4.4% (0.6 g per 100 g of eggs)
Beef: 4.8% (1.2 g per 100 g of beef)
Skim milk: 8.1% (0.3 g per 100 g of milk)
Tofu: 9.1% (0.6 g per 100 g of tofu)
White rice: 11.1% (0.3 g per 100 g of rice)
Corn: 16.2% (0.4 g per 100 g of corn)

Ideal Amounts of L-Glutamine

Studies have shown that 0.5g l-glutamine per kg body weight can be beneficial for therapeutic effects, such as improved gut health, and mood/well-being. (VIII)

Furthermore, there have been reports which show that 28g of glutamine can be tolerated without ill effect in athletes. (IX) For most people, suggested dosages range between 5g and 20g per day – which shows great results.

Sport Nutrition Expert Recommendation

If you only thought that l-glutamine was just for healing your leaky gut syndrome, then think again!

L-glutamine is an essential amino acid that’s responsible for healing large parts of the human body. These include; easing depression and reducing oxidative stress to help the body naturally regenerate itself.

I recommend using l-glutamine if you’re serious about strength training, or if you want to begin the healing process within your gut. That’s because l-glutamine is an important supplement for growth hormone production, and the reduction of inflammation while protecting your intestines.

Studies indicate that high doses of 28 grams per day have resulted in positive adaptations to heal and strengthen the body. For an accurate dosage, aim to consume 0.5g l-glutamine per kg of body weight.

If you’re looking to increase your glutamine intake with food. Try eating more grass-fed whey protein, meat, milk, nuts, lentils, seeds and tofu. All of which contain high amounts of l-glutamine.

Remember, that large amounts of glutamine can be lost through exercise, stress, and also surgery. Along with some forms of medication such as antibiotics. However, the good news is, glutamine can be replenished quickly with great effect.

References

(I) Wischmeyer, Paul E, et al. “Parenteral Glutamine Supplementation in Critical Illness: a Systematic Review.” Critical Care (London, England), BioMed Central, 18 Apr. 2014. (source)

(II) Lee, Younghyurk, et al. “Glutamine Deficiency in the Prefrontal Cortex Increases Depressive-like Behaviours in Male Mice.” Journal of Psychiatry & Neuroscience : JPN, Canadian Medical Association, May 2013. (source)

(III) Mansour, Asieh, et al. “Effect of Glutamine Supplementation on Cardiovascular Risk Factors in Patients with Type 2 Diabetes.” Nutrition (Burbank, Los Angeles County, Calif.), U.S. National Library of Medicine, Jan. 2015. (source)

(IV) Bartke, Andrzej. “Growth Hormone and Aging: a Challenging Controversy.” Clinical Interventions in Aging, Dove Medical Press, Dec. 2008. (source)

(V, VI) Welbourne, T C. “Increased Plasma Bicarbonate and Growth Hormone after an Oral Glutamine Load.” The American Journal of Clinical Nutrition, U.S. National Library of Medicine, May 1995. (source)

(VII) Ban, Kechen, and Rosemary A Kozar. “Glutamine Protects against Apoptosis via Downregulation of Sp3 in Intestinal Epithelial Cells.” American Journal of Physiology. Gastrointestinal and Liver Physiology, American Physiological Society, Dec. 2010. (source)

(VIII, IX) Gleeson, Michael. “Dosing and Efficacy of Glutamine Supplementation in Human Exercise and Sport Training.” The Journal of Nutrition, U.S. National Library of Medicine, Oct. 2008. (source)