Not getting enough sleep?
Sleep disorders are extremely common. They affect millions of people around the world. The amount of sleep needed varies from person to person. For adults between 7.5 and 9 hours is ideal. However, many people don’t meet this requirement and often experience a broken night’s sleep.
There are many different types of sleep disorders; some are chronic, while others may be a passing phase. Either way, everyone experiences difficulties sustaining healthy sleep patterns at some stage in their life.
The good news is that there are ways to naturally support normal circadian rhythms without resorting to pharmaceutical interventions. Boosting the body’s availability of certain amino acids can assist in supporting a healthy wake-sleep cycle.
Glycine is a non-essential amino acid produced by the body. One of its roles is as an inhibitory neurotransmitter. Within the nervous system this amino acid reduces neuron activity and helps to relax the body.
Researchers have also found that glycine is involved in lowering the body’s core temperature and relaxing blood vessels1. These processes are all important for preparing the body for sleep onset and improving sleep quality.
Clinical studies have shown that increasing the availability of glycine can help to improve sleep quality. In a randomized double-blinded cross-over trial volunteers with poor sleep patterns were given either a placebo or 3g of glycine prior to bedtime2.
The following morning participants completed a Space-Aeromedicine Fatigue Checklist and the St. Mary’s Hospital Sleep Questionnaire to determine their sense of wellness and restfulness. Volunteers reported a significantly improvement in fatigue and liveliness after taking glycine compared with the placebo.
Another study investigated the effects of glycine on healthy male volunteers with no reported sleep difficulties3. These volunteers spent an average of 7.3 hours in bed. During the study the participants were either given 3g of glycine or a placebo and their time in bed was reduced to 5.5 hours for 3 consecutive nights.
Researchers found that the men taking the glycine supplement reported minimal adverse effects. Conversely, the men taking the placebo had higher levels of fatigue, daytime drowsiness and reduced cognitive function.
One of the common problems affecting sleep quality is stress and anxiety. These heightened moods can make it very difficult for the body to relax and prepare for sleep, significantly interrupting circadian rhythms. This is where the essential amino acid L-tryptophan can help.
L-tryptophan is essential for the production of serotonin and is therefore vital for regulating behaviour, mood, and cognitive function4. Consequently it is often prescribed to help treat psychiatric disorders5.
L-tryptophan is converted in the central nervous system into neurotransmitters such as serotonin to balance mood and support relaxation. Serotonin is an essential precursor to the hormone melatonin.
To maintain a healthy wake-sleep cycle the body requires sufficient availability of melatonin. Thus, indirectly L-tryptophan is an essential amino acid critical for maintaining good sleeping patterns.
Researchers have investigated the effects of L-tryptophan and have found that different quantities of this amino acid have varying effects on sleep patterns. Volunteers with mild insomnia were administered either 0.25g of L-tryptophan or 1g or L-tryptophan before going to bed6.
The study found that volunteers administered 0.25g of L-tryptophan showed a significant increase in delta-wave restorative deep sleep patterns. Volunteers administered 1g of L-tryptophan fell asleep significantly faster than normal. Other studies have confirmed these findings, with researchers recommending between 1 and 2g for optimal results.
Other studies have found that L-tryptophan can also help to relieve obstructive sleep apnea7. However, little evidence suggests that it may assist with central sleep apnea.
L-theanine is an amino acid analogue formed from the amino acids L-glutamine and L-glutamate. This amino acid is highly concentrated in tea leaves. L-theanine crosses the blood barrier to directly influence brain neurotransmitters. It has a calming and soothing effect, which can be beneficial for people that have trouble relaxing and falling asleep.
Animal-based studies have shown that L-theanine is capable of reducing the excitatory effects of caffeine in rats8. This research found that L-theanine improved slow-wave sleep (SWS), and rapid-eye-movement sleep (REMS) duration; both essential for quality sleep.
L-theanine doesn’t cause drowsiness. It promotes relaxation. This amino acid is recommended as an effective natural sleeping aid9.
L-glutamine is a non-essential amino acid involved in a wide range of metabolic processes. Psychological and/or physical stresses on the body will deplete the availability of this amino acid10.
Glutamine increases the production of gamma-amino-butyric acid (GABBA), the most important inhibitory neurotransmitter. Essentially L-glutamine can provide a natural sedative effect, helping to calm and relax the body in preparation for sleep. Having sufficient L-glutamine available is important for a sustaining healthy circadian rhythm.
If you struggle to get a good night’s sleep or would like to feel more relaxed there are amino acids that will help. Ensuring that your body has a sufficient availability of important compounds like L-glutamine, L-theanine, L-tryptophan, and L-Glycine will support normal sleep-wake cycles. Together with regular exercise and other positive lifestyle adjustments, it is possible reinstate a healthy circadian rhythm.
There are plenty of recommended supplements on the market that incorporate these amino acids and other herbal ingredients to improve sleeping patterns. Always consult your doctor first to ensure their suitability.
- “Kawai N, Sakai N, et al. (2015). The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus. Neuropsychopharmacology. Volume 40, Issue 6, (pp. 1405-16).” ↩
- “Inagawa, K., et al. (2006). Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep and Biological Rhythms. Volume 4, Issue 1, (pp. 75-77).” ↩
- “Banna, M. et al. (2012). The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in Neurology. 3:61 doi: 10.3389/fneur.2012.00061.” ↩
- “Richard, D. et al. (2009). L-tryptophan: basic metabolic functions, behavioural research and therapeutic indications. International Journal of Tryptophan Research. Volume 2. (pp. 45-60).” ↩
- Bell, C. et al. (2001). Tryptophan depletion and its implications for psychiatry. The British Journal of Psychiatry. Volume 178, Issue 5, (pp. 399-405).” ↩
- Hartmann, E. and Spinweber C. (1979). Sleep induced by L-tryptophan. Effect of dodages within the normal dietary intake. The Journal of Nervous and Mental Disease. Volume 167, Issue 8, (pp. 497-9).” ↩
- “Schmidt, H. (1983). L-Tryptophan in the treatment of impaired
respiration in sleep. Bull Eur Physiopathol Respir. Volume 19, (pp. 625-29).” ↩
- “Jang, H. et al. (2012). L-theanine partially counteracts caffeine-induced sleep disturbances in rats. Pharmacology Biochemistry and Behaviour. Volume 101, Issue 2, (pp. 217-221).” ↩
- “Halson, S. (2014). Sleep in elite athlete and nutritional interventions to enhance sleep. Sports Medicine. Volume 44, Issue 1, (pp. 13-23).” ↩
- “Bowtell, J.L., et al. (1999). Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. Journal Of Applied Physiology. Volume 86, Issue 7, (pp. 1770-1777).” ↩