L-glutamine

What is glutamine?

Glutamine is a naturally occurring semi-essential amino acid found in food. Semi-essential in this context means that the body can produce glutamine itself to a certain extent from other amino acids when needed, but in certain situations of increased glutamine demand, this amount is not sufficient to meet the body's needs. As a result, there are situations such as trauma or extreme physical exertion where body proteins such as muscle protein must be broken down to provide additional glutamine if the body is not supplied with sufficient amounts of glutamine through food or supplements.

Glutamine is closely related in structure to glutamic acid. They can be converted into each other. In humans and all mammals, only the L-form of these two amino acids occurs. Glutamine was isolated from beet juice in 1883, but was only isolated from gliadin, a wheat protein, in 1932 and chemically synthesized a year later. Glutamic acid was isolated from wheat in 1866 and synthesized in 1890. It is mainly found in plant proteins.

These can contain up to 45 percent glutamic acid, whereas other proteins often only contain 10 to 20 percent. Glutamine is very important for the cell metabolism of mammals and is the only amino acid that can pass the barrier between blood and brain very quickly. It can be produced by the human body in small quantities as required if there is a lack of glutamine-rich sources in the diet. However, the majority is obtained from food.

What does the body need glutamine for?

The human digestive tract relies on glutamine as an energy source and sufficient amounts of glutamine are also required for the immune system to function properly. At the same time, the body uses large amounts of glutamine during intensive training sessions, which means that the body's own glutamine levels can be reduced by up to 50% after training.

Why can glutamine supplementation be beneficial for athletes?

Glutamine can provide the body with an alternative source of energy for exercised muscles during training, thereby increasing muscle performance and endurance. As the body therefore uses large amounts of glutamine during an intensive training session, glutamine supplementation after training can accelerate muscle recovery and prevent the body from having to break down muscle protein in order to obtain glutamine needed for other important bodily functions.

As glutamine promotes the function of the immune system, it can help athletes to better protect themselves against infectious diseases such as colds or flu, which can result in unwanted breaks in training. In the case of an existing infection, glutamine can help speed up the healing process by stimulating the immune system. As an added bonus, like creatine, glutamine can increase the volume of muscle cells and give muscles a fuller appearance, while when taken on an empty stomach it can increase the body's production of growth hormone by up to 400%.

What are the main benefits of glutamine?

• Support regeneration after training
• Prevents muscle breakdown, which can occur when the body needs more glutamine than it can produce itself or is supplied through food
• Has a cell volumizing effect similar to that of creatine
• Can increase the body's own growth hormone release by up to 400% when taken on an empty stomach
• Supports the function of the immune system and reduces susceptibility to infectious diseases

Glutamine and glutamic acid have important functions in the body

Glutamine is the amino acid with the highest levels in the human body and the most important non-essential source of nitrogen. Glutamine is the precursor substance of GABS, gamma-aminobutyric acid. This is a neurotransmitter in the brain that has a calming and soothing effect on the nerve pathways. Well-known tranquilizers and sleeping pills such as benzodiazepines develop their effect by stimulating GABS in the brain. Of all amino acids, glutamine has the highest concentration in the blood and in muscle tissue.

It is broken down there to generate energy. Glutamine is generally the most important source of energy in the cells. It contributes to the synthesis of genetic building blocks. Therefore, all body cells that divide or renew themselves frequently have a high demand for glutamine. This is particularly true for the cells of the intestinal walls and leukocytes (white blood cells). In this way, glutamine can also strengthen the immune system, especially during periods of severe physical stress.

Glutamine can be converted to glucose in the liver, which can stabilize blood sugar levels in the body. Together with cysteine and selenium, glutamine is also a starting material for the formation of glutathione, a vital antioxidant in the tissue. Glutamic acid is produced by the hydrolysis (splitting by water) of proteins and the conversion of glutamic acid to glutamine is very important for the regulation, breakdown and excretion of ammonia in the body.

Enriched in the muscle cell, glutamine exerts an osmotic pressure, i.e. glutamine retains water in the muscle and thus creates the conditions for optimal protein synthesis. Accordingly, studies have shown that the muscle cell is put into an anabolic state when glutamine is administered. A targeted supply of glutamine after physical exertion can reduce susceptibility to infections in athletes. Interestingly, one study showed an increase in growth hormone, which has an anabolic and fat-burning effect, as well as in plasma bicarbonate levels, an important acid buffer system in the body.

Bicarbonate helps to reduce the accumulation of lactate in the muscles, which occurs during training, so that strength athletes who take glutamine before training can complete more repetitions. It can increase growth hormone levels, improve concentration and possibly reduce cravings for sweets.

The main sources of glutamine and glutamic acid

Many protein-rich foods contain plenty of glutamic acid, such as poultry, fish and vegetables, especially beets, carrots and radishes. Glutamine and GABS, on the other hand, are rarely found as specific substances in food.

Typical groups for an increased requirement of glutamine and glutamic acid

During physical stress, for example after injuries, operations and chronic illnesses, there is an increased need for glutamine in the intestines, liver and immune system. The body's own production is then no longer sufficient to cover the additional requirement. Supplementation together with other amino acids is particularly recommended if the protein supply is generally too low. Glutamine can have a preventative effect in the case of a tendency to stomach ulcers and gastritis due to excessive intake of aspirin or alcohol and can help to reduce damage to the stomach walls. In the case of alcoholism, glutamine can also reduce cravings for alcohol and reduce anxiety.

The need for glutamine and glutamic acid may be increased in the following conditions, ailments and diseases:

• in competitive sports and hard physical work
• in the case of heavy physical strain (e.g. due to injuries, operations, illnesses)
• a tendency to stomach ulcers and gastritis
• nervous strain and tension
• with high alcohol consumption

Can glutamine and glutamic acid be overdosed or are there side effects?

At relatively high doses (up to 21 grams per day), glutamine is not known to have any toxic effects. Excessive doses may cause reddening and tingling of the skin. People suffering from manic depression or epilepsy should avoid high doses of glutamine. They can increase the glutamate levels in the brain too much. This can possibly worsen mania or epilepsy. Monosodium glutamate (MSG) is a monosalt of L-glutamic acid. This can be used as an additive in foods (E620 - E625). MSG is often held responsible for the so-called "quinine syndrome". Sensitized people can apparently experience palpitations and headaches after consuming it.

Optimal dosage

Based on feedback from athletes who have used glutamine, the following dosing regimes seem advisable:

• 4-6 doses of 2-4g of glutamine throughout the day
• 5-10g of glutamine before and after training, or
• 10-15g of glutamine immediately after training and another 10-15g one and a half to two hours later.

When taking glutamine, the athlete experiences improved regeneration, a better pump during training and a slight increase in physical strength. Some athletes also experience an increase in lean body weight within the first few days of taking glutamine, similar to, but less than, the intake of creatine. This is probably due to increased glycogen storage and an increased water content in the muscles.

Precautions and warnings:

Pregnancy and lactation: not enough is known about the safety of glutamine during pregnancy and lactation. For this reason, pregnant and breastfeeding women should avoid glutamine to be on the safe side.

Severe liver disease with difficulty thinking or confusion (hepatic encephalopathy): Glutamine could aggravate this condition and should therefore not be used by people suffering from this condition.

Sodium glutamate hypersensitivity: If you are sensitive to sodium glutamate, you may also be sensitive to glutamine, as the body converts glutamine to glutamate.

Mania or mental disorders: Glutamine could cause mental changes in people who are prone to mania.

Seizures: There are concerns that glutamine may increase the risk of seizures in some people. For this reason, people who are prone to seizures should avoid glutamine.

Interactions

Care should be taken when combining glutamine with the following medications:

Lactulose

Lactulose helps to reduce ammonia levels in the body. Glutamine is converted into ammonia in the body. Taking glutamine in combination with lactulose could reduce the effectiveness of lactulose.

Cancer drugs (chemotherapy)

There are concerns that glutamine may reduce the effectiveness of some anti-cancer drugs. It is too early to say how this interaction occurs.

Drugs used to prevent seizures (anticonvulsant drugs)

Drugs used to prevent seizures affect certain chemicals in the brain. Glutamine may also affect chemicals in the brain. As a result, glutamine may reduce the effect of medications used to prevent seizures.

Buying glutamine

Glutamine is available in various dosage forms. In addition to capsules, the powder form is the most popular, as it can easily be mixed with other supplements such as protein powder. Alternatively, the powder can be dissolved in water or juice.

As with other supplements, the quantity of the active ingredient - in this case glutamine - should be used as a quality factor.

The 100% Pure L-Glutamine from B.A.M., the Hospitaller Glutamine Sword Brothers from Gods Rage or the Glutamine Polyhydrate from GN Laboratories are among our bestsellers for this reason.

References

1. J Appl Physiol. 1999 Jun;86(6):1770-7. Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. Bowtell JL, Gelly K, Jackman ML, Patel A, Simeoni M, Rennie MJ.
2. Am J Surg. 2002 Apr;183(4):471-9. Reversal of cancer-related wasting using oral supplementation with a combination of beta-hydroxy-beta-methylbutyrate, arginine, and glutamine. May PE, Barber A, D'Olimpio JT, Hourihane A, Abumrad NN.
3. Curr Opin Clin Nutr Metab Care. 2002 Jan;5(1):69-75. glutamine: clinical applications and mechanisms of action. Neu J, DeMarco V, Li N.