GABA - Gamma aminobutyric acid: neurotransmitter, role and supplements

What is gamma-aminobutyric acid (Gaba)?

Gamma-aminobutyric acid (GABA) is a neurotransmitter, a chemical messenger in the brain. It slows down the brain by blocking specific signals in the central nervous system (brain and spinal cord).

GABA is known to produce a calming effect. It is believed to play an important role in controlling nerve cell hyperactivity associated with anxiety, stress, and fear.

Scientists also call GABA a non-protein amino acid neurotransmitter.

How does gamma-aminobutyric acid (GABA) work?

GABA is the most common inhibitory neurotransmitter in the central nervous system. Inhibitory neurotransmitters prevent or block chemical messages and decrease stimulation of nerve cells in the brain.

Neurotransmitters generally all function in the same way. They are chemical messengers that carry messages from one nerve cell in the brain to the next. Between each nerve cell is a small amount of fluid-filled space called a synapse. Neurotransmitters must carry their message across this synapse and then land and bind to specific receptors on the next nerve cell (like a key that can only fit and work in its partner's lock).

There are two types of GABA receptors on nerve cells: GABA-A and GABA-B. Although they function in different ways, when GABA binds to these receptors the result is that they decrease the responsiveness of the nerve cell. This means that as an inhibitory neurotransmitter, GABA reduces a nerve cell's ability to receive, create, or send chemical messages to other nerve cells.

What are the health benefits of GABA?

By slowing down certain brain functions, GABA is believed to:

• Reduce stress.
• Relieve anxiety.
• Improve sleep.

What is the relationship of GABA with glutamate?

GABA and glutamate act like an "on" and "off" switch. They function in opposite ways. GABA is the main inhibitory neurotransmitter in the brain, preventing chemical messages from passing from one nerve cell to another. Glutamate, on the other hand, is the main excitatory neurotransmitter in the brain, allowing chemical messages to be carried from one nerve cell to another.

To have a properly functioning brain, a delicate balance must be maintained between the inhibitory effects of GABA and the excitatory effects of glutamate. GABA also functions together with another neurotransmitter, serotonin. In fact, many neurotransmitters work together and against each other and must maintain a certain relationship to achieve proper functioning of the body and brain.

GABA is actually made up of glutamate as a result of a reaction with the enzyme glutamic acid decarboxylase.

What medical conditions are associated with changes in GABA levels?

Some neurological and mental health conditions are thought to be related to times when GABA messaging ("signaling") activity is out of balance and not functioning as it should. Decreased GABA activity may contribute to:

• Anxiety and mood disorders;
• Schizophrenia;
• Autism spectrum disorder;
• Depression;
• Epilepsy; Seizures.

Other medical conditions associated with GABA imbalance include:

• Pyridoxine deficiency. This is a rare disorder in which the vitamin needed to produce GABA is unavailable. It usually causes frequent seizures in childhood. Seizures are not successfully treated with anticonvulsant drugs, but respond to vitamin supplementation.
• Hepatic encephalopathy;
• Huntington's disease;
• Dystonia and spasticity;
• Hypersomnia (excessive daytime sleepiness or excessive time spent sleeping).

Does increasing GABA levels provide health benefits?

Researchers are still studying the effects of increased GABA levels. Although the evidence is unclear, GABA is being examined to help treat or prevent health conditions including:

• Hypertension;
• Insomnia;
• Diabetes.

What drugs target GABA?

Many drugs that target GABA receptors have been developed. These include:

• Benzodiazepines. This class of drugs, which includes diazepam (Valium®) and alprazolam (Xanax®), acts on the GABA-A receptor. Benzodiazepines are used in surgical anesthesia, treatment of epilepsy, REM sleep disorders, alcohol withdrawal, anxiety, essential tremor, and muscle spasticity.
• Barbiturates. These are sedative drugs.
• Vigabatrin (Sabril®). This is a drug used to treat seizures and spasms in infants.
• Flumazenil (Romazicon®). This drug is used to treat benzodiazepine overdose. It is also used to improve the mental status of people with hepatic encephalopathy.
• Valproic acid. This drug is a mood stabilizer and an antiepileptic drug.
• Zolpidem (Ambien®, Edluar®). This is a sedative-hypnotic. It is used to treat insomnia.
• Gabapentin (Neurontin®, Gralise®, Horizant®). This drug is used to treat seizures and nerve pain.
• Propofol (Diprivan®). This drug is a sedative used in general anesthesia.
• Baclofen (Lioresal®, Gablofen®). This drug is a muscle relaxant.

Is a GABA supplement available?

GABA is available as a dietary supplement. However, much of it may not make it into your brain. (Technically, this is called "crossing the blood-brain barrier." The barrier is a unique membrane that allows only certain molecules to cross it to and from the brain.) Thus, it is not known what effects, if any, taking dietary supplements of GABA may have on the brain. So far, there is no solid scientific evidence to support the use of a GABA supplement to treat medical conditions. More studies, in larger numbers of people, are needed.

Is GABA present in foods?

GABA is present in some fermented foods, including kimchi, miso, and tempeh. It is also found in green, black, and oolong tea. Other foods that contain GABA or increase its production in the body include brown rice, soybeans and adzuki beans, chestnuts, mushrooms, tomatoes, spinach, broccoli, cabbage, cauliflower, Brussels sprouts, sprouted grains, and sweet potatoes.

Like supplements, it is not entirely clear whether eating foods containing GABA allows GABA to reach the brain. More studies need to be conducted, on a large number of people.

Note de disclaimer

Gamma-aminobutyric acid (GABA) is the most common inhibitory neurotransmitter in the central nervous system. GABA reduces the ability of a nerve cell to receive, create, or send chemical messages to other nerve cells. GABA is known to produce a calming effect. It is believed to play an important role in the control of anxiety, stress and fear. Reduced levels of GABA are associated with several neurological and mental health conditions, as well as other medical conditions. Increased levels of GABA can help treat hypertension, diabetes, and insomnia. Because of the abundance of GABA in the brain, the GABA receptor is a major target of drug development by pharmaceutical manufacturers. The effectiveness of GABA supplements and GABA-containing foods to prevent and treat medical conditions needs to be studied in more people. Before buying GABA supplements or eating certain GABA-containing foods, talk to your doctor about the best approach to treating your health condition.