5 HTP and Sleep Apnea

What is Sleep Apnea?

Sleep apnea is a type of sleep disorder that involves abnormal breathing pauses while sleeping.

Sleep apnea can either be central or obstructive. While central sleep apnea is caused by a lack of respiratory drive, there is respiratory drive in obstructive sleep apnea but the breathing pauses are caused by physical blockage of the path taken by airflow.

Because of the physical obstruction, snoring usually accompanies obstructive sleep apnea.

Both central and obstructive sleep apnea may affect the same patient. This is called mixed sleep apnea. Of the 3 types of sleep apnea, obstructive sleep apnea (OSA) is the most common (8 in 10 cases of sleep apnea is OSA).

Most people suffering from sleep apnea are unaware of any cessation in breathing, and the condition is only diagnosed with an overnight sleep test called a polysomnogram.

The major symptoms of sleep apnea are fatigue diminished mental focus and drowsiness during the day. Patients may also suffer from slow reflexes, vision problems, moodiness, and irritability.

Sleep apnea has also been shown to be associated with an increased risk of memory loss, high blood pressure, diabetes, stroke, and cardiovascular diseases.

The obstruction of airflow can also lead to some degree of brain injury caused by repeated drops in oxygen supply to brain tissues.

The treatment of sleep apnea is just about what to avoid as to what to use.

For example, anything that contributes to the relaxation and collapse of throat muscles should be avoided. Therefore, sedatives and alcohol should be avoided.

The major treatment for sleep apnea include devices that provide positive airway pressure such as CPAP (continuous positive airway pressure) and APAP (automatic positive airway pressure). When these devices fail or are uncomfortable for patients, surgery is the last option in conventional medicine.

The Link Between Tryptophan, 5 HTP, and Serotonin

5 HTP, also known as 5-hydroxytryptophan, is a naturally occurring amino acid that serves as the direct precursor of serotonin, an important monoamine neurotransmitter in the brain.

5 HTP itself is synthesized from another amino acid called L-tryptophan which is one of the essential amino acids. Although 5 HTP occurs in nature, it is not found in the foods we eat. Instead, 5 HTP is supplied in the form of dietary supplements.

The 5 HTP included in dietary supplements is sourced from the seeds of an African plant, Griffonia simplicifolia.

Ultimately 5 HTP is needed in the body for the sole purpose of increasing serotonin levels. However, in the synthesis of serotonin, the conversion of L-tryptophan to 5 HTP is the most delicate step. 5 HTP supplements bypass this weak link in serotonin synthesis by directly supplying the immediate precursor of serotonin.

Both tryptophan and 5 HTP can cross the blood-brain barrier but 5 HTP crosses more readily.

Tryptophan, on the other hand, faces stiff competition from other amino acids. First, only 1% of the amino acid content of dietary protein is tryptophan. Secondly, tryptophan does not fare well as all amino acids compete to cross into the brain. Thirdly, tryptophan shares the same transport mechanism as valine, leucine, and isoleucine to cross the blood-brain barrier.

In contrast, 5 HTP faces no such restrictions, and, therefore, it is the better supplement to take to improve serotonin levels in the brain.

The Effects of Serotonin

Serotonin or 5 HT is produced from 5 HTP and the reaction is catalyzed by the enzyme, 5 HTP decarboxylase, and also vitamin B6.

Once produced, serotonin, like all neurotransmitters, is used for transmitting certain signals between nerve cells in the brain. To produce its effects, serotonin must bind to a set of receptors called serotonin or 5 HT receptors.

There are 7 classes of serotonin receptors numbered from 5 HT1 to 5 HT7. These are found in the central nervous system as well as the cardiovascular, musculoskeletal, and endocrine systems. Therefore, serotonin acts on these other organ-systems.

However, serotonin receptors also control the release of other neurotransmitters such as dopamine, GABA, glutamate, acetylcholine, norepinephrine, and epinephrine. In the endocrine system, some of these receptors also perform the same functions for hormones such as cortisol, vasopressin, oxytocin, prolactin, and substance P.

The drugs that act on the serotonergic pathway bind to serotonin receptors to trigger the release of these neurotransmitters and hormones or block them. Therefore, each of the serotonin receptors can produce either an excitatory or inhibitory response.

The widespread of the serotonergic system means that serotonin can produce a long list of effects in different parts of the body.

In the central nervous system, serotonin controls mood, sleep, and appetite. It is also involved in memory and learning. In the circulatory and cardiovascular system, serotonin causes vasoconstriction, regulates blood clotting, and promotes the repair of damaged tissues.

Studies on 5 HTP and Sleep Apnea

Most of the studies involving 5 HTP in the field of sleep apnea agree that 5 HTP supplementation helps relieve the symptoms of the sleep disorder and that cortisol is involved in the process.

In a 1995 study published in the American Journal of Respiratory and Critical Care Medicine, the change in the level of cortisol was measured with 5 HTP supplementation. The study involved 11 patients with sleep apnea and 11 controls.

The study result showed that the patients with obstructive sleep apnea who received 5 HTP had higher cortisol levels even though their cortisol levels were the same as the non-apnea patients before the study.

The researchers believed that 5 HTP supplementation increased the production of 5 HT or serotonin which then acts on the hypothalamus to trigger the release of CRH (corticotropin-releasing hormone) and then cortisol.

Cortisol is a glucocorticoid released from the adrenal glands in response to stress especially sleep deprivation.

In a follow-up study published in 2007 in the journal, Chest, the same group of researchers demonstrated that the rise in cortisol levels caused by increased serotonin production following 5 HTP supplementation is reversed by such sleep apnea treatment as CPAP.

Another study was done on mice and published in the journal, Sleep, concluded that both low and high levels of serotonin in the brain can cause sleep apnea but an optimal level of the neurotransmitter is needed for maintaining a constant respiratory drive and a clear airway during sleep.

How to Use 5 HTP for Sleep Apnea

5 HTP may be a very effective dietary supplement for treating insomnia but there has only been limited success for its use in the treatment of sleep apnea.

However, patients with abnormally low levels of serotonin can benefit greatly from taking 5 HTP. In this way, 5 HTP provides an excellent and safe way to return serotonin levels to optimal.

An optimal level of serotonin is required because the nerves that serve the muscles needed for breathing need serotonin. Therefore, the breathing muscles may collapse and block airflow if they are not properly stimulated by the serotonin neurons.

On the other hand, if the level of serotonin goes up too much, sleep is deepened too much and proper control of the same breathing muscles is lost.

Therefore, serotonin levels and 5 HTP supplementation in the management of sleep apnea requires a fine balance.

Where sleep apnea is caused by low serotonin levels, 100 mg – 300 mg of 5 HTP is recommended to be taken before bedtime.