What Is Glutamine?
Glutamine is one kind of amino acid and plenty of this amino acid is available in the human body. Glutamine is very important for the human body and plays an important role in boosting the immune system and carbohydrate metabolism.
In fact, glutamine aids in protein production in the human body. This α-amino acid aids in the biosynthesis of proteins.
Types of Glutamine
There are two types of glutamine. These are l-glutamine and d-glutamine with different molecular structures.
The D-enantiomer of glutamine is called D-glutamine. It is a non-essential amino acid and is not popular as L-glutamine.
In fact, there is not plenty of research on D-glutamine.
Among the two types of glutamines, L-glutamine is widely used for its health benefits. People also call it glutamine.
Our body can naturally process L-glutamine. In fact, healthy people weighing about 70 kg have a distribution of 70 to 80 g of glutamine throughout the whole body (1). Isotopic and pharmacokinetic techniques have estimated that glutamine production is between 40 to 80 g/day (2).
Glutamine is also found in foods like almonds, peanuts, chicken, fish, egg, dairy, beef, carrots, beans, cabbage, spinach, lobsters, shrimps, etc. Also, several glutamine supplements are widely available on market.
The benefit of L-glutamine/glutamine
Although glutamine is a non-essential amino acid, it provides numerous health benefits. Our immune system consumes a similar or greater amount of glutamine compared to glucose to prevent the human body from diseases.
Glutamine is an essential nutrient for neutrophil bacterial killing. Moreover, this important amino acid aids in lymphocyte proliferation and cytokine production.
In fact, glutamine falls under clinical nutrition supplementation protocols and it is recommended for immune-suppressed individuals.
Another study has shown that glutamine supplementation may have a positive effect on fasting plasma glucose and C-reactive protein. Both of these are very crucial elements for cardio-metabolic risk factors (3).
Also, glutamine is an important nutrient for the proliferation of lymphocytes. It also helps to maintain a healthy metabolism during catabolic and hypercatabolic conditions (4).
Some other benefits which may be achieved from glutamine supplementation or natural consumption from organic foods are (5, 6, 7):
- Improvement of insulin sensitivity
- Prevention of obesity
- Reduction of body weight(belly fat and waist circumference)
- Lowering systolic blood pressure
- Reduction of fasting blood glucose concentration
- Constipation cure
Glutamine/L-glutamine Daily Dosages
Although a wide range of clinical trials was conducted on different doses of glutamine supplementation the best-supplementing regime is not finalized.
These trials contained a limit of less than 0.1 gram of glutamine against per kg body weight to a fixed dose of 20-35 grams per day. However, the accurate intake level is yet to be discovered.
However, 0.1 to 0.3 grams of glutamine against per kg of body weight may normalize plasma glutamine concentration for critically ill patients (7). That’s why 0.1 g to 0.3 g /kg may be a perfect dose.
Moreover, another study has shown that a high daily intake of 0.75 grams against per kg body weight can increase glutamine pool without a sign of potential glutamate-mediated cerebral injury (8).
So, 0.75 g/kg/d glutamine may be in a risk-free consumption zone.
Side effects of Glutamine
Although glutamine is a health-promoting nutrient, it may cause some adverse effects in case of too much consumption.
The exertion of glutamine from the liver is increased during physical activities. Our kidneys and immune system cells use more glutamine in this period.
Excess intake of glutamine supplements may create pressure on the kidneys during this time. Also, a study has shown that high plasma glutamine levels may cause liver failure (9).
Another recent study has found glutamine-induced hepatotoxicity in a female athlete. However, by stopping glutamine supplementation the patient recovered within two weeks (10).