Are brain health and quality sleep a possible health benefit of L-serine?

Researchers have long marveled at the widespread longevity of the Okinawa population. Unlike mainland Japan, Okinawa is an ethnically diverse and culturally distinct island. Historically, the Japanese called the island "the land of longevity" because the Okinawans, who live to over 80 years old, seem to have an extraordinary ability to live longer.
Studies in the early 2000s linked the Okinawans' unique longevity secret to their high intake of fish, soy, seaweed, and green vegetables. However, as researchers dug deeper, new insights provided new perspectives on health and longevity. One of these new insights is that the Okinawans' diet is high in an amino acid called L-serine.In addition to potentially helping to strengthen immune function, regulate sleep patterns, and relieve chronic fatigue syndrome, L-serine also plays a vital role in brain development and nerve conditioning. Specifically, it's this nutrient that gives Okinawan cuisine, or the Ogimi diet, its life-nourishing power.
The average life expectancy of the Okinawans is over 83 years, significantly higher than in the rest of the world. Some developed countries are close to this average, but Europe, Russia, China and the United States still have a long way to go.

What is L-serine?

L-serine is a "conditionally non-essential amino acid" and one of the important amino acids in the survival and growth of the human body. L-serine is involved in many metabolic processes, including protein production, the synthesis of lipids, nucleic acids, neurotransmitters (such as serotonin), and the production of other amino acids. L-serine is an amino acid required for the production of phosphatidylserine. As a phospholipid, phosphatidylserine is an important component of cell membranes.
Although it is not one of the nine essential amino acids that the human body cannot synthesize on its own, L-serine plays a critical role in some cases. For example, in neurodegenerative diseases such as diabetes or Alzheimer's disease, the body's own production of L-serine cannot meet the body's needs for this nutrient. Therefore, it is necessary to supplement L-serine, and it is quite appropriate to describe L-serine as "conditionally non-essential".
Serine and its many metabolites are still being studied and are expected to be used in the treatment of diabetes, various kidney diseases, brain injuries, and various neurological and psychiatric diseases. Below are some of the health benefits of L-serine that are popular.

Possible Health Benefits for the Brain

L-serine may help optimize brain health and cognitive function. There is growing evidence that L-serine may control inflammatory responses in the brain, helping to restore mental function in disease states. It may also regulate blood flow in the brain, assist in the formation of myelin (an insulating layer around neurons), and act as a neurotrophic factor (protein) to support neuronal growth and survival.
L-serine may also prevent glutamate neurotoxicity. Glutamate neurotoxicity is a neurotransmitter that, when in excess, can cause damage to cellular components and lead to neuronal death in brain injury conditions such as ischemia (reduced blood flow), trauma, or hemorrhage.
Unfortunately, aging causes a decrease in the level of D-serine in the brain, which is related to L-serine, leading to insufficient activation of N-methyl-D-aspartate receptors (NMDA receptors), resulting in brain degeneration and memory loss. Therefore, according to research, D-serine may also help prevent age-related mental decline and memory loss. In addition, recent studies have also shown that D-serine may serve as an adjunct therapy for depression and schizophrenia and help alleviate cognitive decline.
In addition, L-serine is an essential amino acid in the synthesis of a chemical called phosphatidylserine, which plays a key role in many functions such as cell protection, neurotransmission and memory formation. Studies have shown that phosphatidylserine may improve cognitive function, relieve brain inflammation, and prevent diseases such as Alzheimer's disease and mental illnesses such as depression and schizophrenia. This shows that L-serine may play a much more important role in brain health than previously thought.
Brain diseases such as Alzheimer's disease, mental illnesses such as depression and even schizophrenia have become common diseases. According to the Centers for Disease Control and Prevention (CDC), Alzheimer's disease has become the fourth leading cause of death in the United States, and as many as 6.5 million Americans suffer from the disease every day. It is believed that as many as 50 million people worldwide are suffering from the disease.
Much effort has been devoted to understanding the causes of mental illnesses such as Alzheimer's disease, Parkinson's disease, and schizophrenia. Recent studies suggest that L-serine, like several other substances, may play a role in neurodegenerative and psychiatric disorders.
A study published in the Journal of Cell Metabolism suggests that impaired production of L-serine in brain cells that may aid memory (hippocampal astrocytes) may contribute to cognitive deficits in Alzheimer's disease. Additionally, a 2021 laboratory study suggests that L-serine may have a neuroprotective effect against Alzheimer's disease by helping to destroy harmful proteins in the disease. Similar results have been observed in laboratory mice with Parkinson's disease, a brain disorder caused by the loss of specific neurons that can lead to unexpected or uncontrollable motor behaviors.
Human studies also support these ideas, suggesting that L-serine is safe and well tolerated. For example, an initial trial involving 20 patients with ALS (amyotrophic lateral sclerosis, or Lou Gehrig's disease) showed that oral L-serine seemed to help slow the progression of the disease. Similarly, according to a 2021 study, L-serine may also have a positive effect on schizophrenia and other neurodegenerative diseases. The potential preventive effects of L-serine on Alzheimer's disease are still under investigation, but it seems to have positive results. However, large-scale clinical trials are still needed to draw objective conclusions.

Possible Benefits for Fibromyalgia and Fatigue

Fibromyalgia is a chronic disease that causes pain and tenderness throughout the body, along with fatigue, sleep, memory, and mood problems. Studies have shown that low levels of serotonin in the body are associated with fibromyalgia syndrome. Fibromyalgia is also associated with changes in the gut microbiome, which can lead to mitochondrial dysfunction. Serotonin, which is also produced in the gut, is a particularly critical neurotransmitter in the nervous system that can affect a range of issues, including mood, digestion, and sleep.
Tryptophan is an amino acid required for the synthesis of serotonin. In addition to the required tryptophan from food, the body can also synthesize tryptophan from L-serine. Therefore, according to research, increasing L-serine intake may promote tryptophan synthesis and subsequent serotonin production, thereby improving mood, sleep and memory, and may also help control fibromyalgia symptoms.

Possible Benefits for Sleep

Insufficient sleep remains a serious health problem in the United States. Data show that one-third of people in the United States do not get enough sleep, and the same is almost the same in other countries.
However, on the positive side, the intake of L-serine may help alleviate sleep disorders and improve sleep quality. A 2014 Japanese study showed that taking L-serine before bedtime may reduce the number of "night awakenings" in the study group compared to the control group. Another study showed that taking L-serine before bedtime may regulate circadian rhythms, balancing regular wake-sleep cycles.

Possible Benefits for Heart Health

It is no exaggeration to say that cardiovascular disease is currently the leading cause of death in humans worldwide, including in the United States. However, only a small number of people are aware of their condition before symptoms occur. Therefore, taking preventive measures remains a useful way to manage cardiovascular disease risk and lead a healthy life. L-serine may have a protective effect against cardiovascular disease. A 2008 laboratory study showed that supplementing with L-serine can control the conduction of nerve impulses in the heart and blood vessels, thereby significantly controlling blood pressure.
Another study showed that L-serine may have anti-oxidative properties and may have a protective effect on the endothelial cells lining the blood vessels, lymphatic vessels, and heart. However, more research is needed before doctors can recommend L-serine as a prescription for preventing heart disease.

Possible Benefits for Blood Glucose Control

With the steady increase in the incidence of diabetes, obesity has become a global epidemic. Studies have shown that diabetes is associated with altered serine metabolism in the body. According to a 2018 animal study, supplementing with L-serine may provide a new solution for controlling blood glucose. In addition, according to research, L-serine intake may also prevent diabetes complications, especially diabetes neuropathy, a type of nerve damage caused by elevated blood sugar.

Key Points

L-serine is safe to take and well tolerated in human and animal studies. However, for some people, L-serine supplements may upset the stomach, causing bloating or difficulty passing stool.
The best way to increase L-serine levels in your body is to eat more foods rich in this nutrient. However, if you want to take a step ahead with supplementation, talk to your doctor or nutrition professional about starting L-serine supplementation.