L-Serine Health Benefits: From Brain Health to Better Sleep

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Д-р Ерик Мадрид, доктор по медицина Публикувано на 8 март 2023

Researchers have long been fascinated by the exceptional longevity of Okinawans, the ethnically diverse and culturally different inhabitants of Okinawa (an island) from mainland Japan. Historically, the Japanese used to call this island "the land of immortals" due to their remarkable ability to live past 80.

Studies in the early 2000s linked the unique longevity of Okinawans to their higher consumption of fish, soy, seaweed, and green vegetables. However, when researchers took a deep dive, the new insights gave them new perspectives on health and longevity. One of these new insights was that the Okinawan diet is high in the amino acid, L-serine.

In addition to its ability to boost immune function, promote regular sleep, and help those with chronic fatigue syndrome, its role in brain development and neuroprotection makes it essential. The nutrients like these give the Okinawan or ogimi diet, more specifically, the life-enhancing power it has.

The average person in Okinawa lives beyond 83, significantly higher than the rest of the world. And even though the developed world has almost caught up to this average, Europe, Russia, China, and the United States still have a long way to go. So, keep reading, as there is much more to find about this nutrient that may help you enjoy a healthier life.

What Is L-Serine?

Also known as the "conditional non-essential amino acid," L-serine is one of the body's most crucial amino acids for survival and growth. L-serine is involved in many metabolic processes, such as protein creation, lipids, nucleic acid, neurotransmitter synthesis (like serotonin), as well as the production of other amino acids. L-serine is essential for the production of phosphatidylserine, a phospholipid and integral part of cell membranes.

Even though it is not one of the nine essential amino acids that the human body can not synthesize itself, certain circumstances make L-serine extremely important. For example, in diabetes or neurodegenerative disorders like Alzheimer's, the internal production of L-serine cannot keep up with the body's requirements for this nutrient. As a result, l-serine supplementation becomes necessary; hence "the conditionally essential" term is appropriate.

Fortunately, serine and many of its metabolites are currently under investigation as a therapy for diabetes, various kidney diseases, brain injuries, and a wide range of neurological and psychiatric disorders. Here are some of the most sought-after health benefits of l-serine.

Brain Health Benefits

L-serine may help promote brain health and enhance cognitive function. Growing evidence suggests that L-serine inhibits inflammation in the brain, helps recover mental function under diseased conditions, improves blood flow in the brain, promotes remyelination (a layer of insulation around neurons), and serves as a neurotrophic factor—a protein that supports the growth and survival of neurons.

Likewise, L-serine prevents glutamate neurotoxicity—a neurotransmitter that, when in excess, causes damage to the cell components and leads to the death of neurons—during brain injuries, such as ischemia (reduced blood flow), trauma, or hemorrhage (bleeding).

Unfortunately, aging leads to a decline in brain D-serine (related to L-serine) levels and the subsequent under-excitation of NMDA receptors, resulting in brain deterioration and memory loss. Thus, D-serine may help also protect against age-related mental decline and memory loss, according to studies. Additionally, recent research suggests that D-serine may serve as an adjunct therapy for treating depression and schizophrenia and may help reduce cognitive decline.

Furthermore, L-serine is necessary for synthesizing a chemical called phosphatidylserine, which plays a critical role in many functions, including cell protection, neurotransmission, and memory formation. Research suggests phosphatidylserine improves cognitive function, decreases brain inflammation, and prevents diseases like Alzheimer's and psychiatric problems like depression and schizophrenia. Therefore, L-serine may play a far more significant role in brain health than previously believed.

Brain disorders, such as Alzheimer, and psychiatric disorders, such as depression or even schizophrenia, are common. Alzheimer's, for example, has become the fourth leading cause of death in the United States, with as many as 6.5 million Americans living with this condition every day, according to the CDC (Centers for Disease Control and Prevention). It is believed up to 50 million people are affected worldwide.

As a result, significant efforts have been made to understand the causes of mental disorders, including Alzheimer's, Parkinson's, and Schizophrenia. Recent research suggests that, among others, the L-serine metabolism may also play a role in neurodegenerative and psychiatric disorders.

A study published in the Journal Cell Metabolism revealed that impaired L-serine production in the brain cells, which help with memory (hippocampal astrocytes), might contribute to cognitive deficits in Alzheimer's. In addition, a 2021 lab study suggests that L-serine may have neuroprotective effects against Alzheimer's by promoting the destruction of the harmful proteins characteristic of Alzheimer's. Researchers also observed similar results in lab mice with Parkinson's, a brain disorder caused by the loss of specific neurons resulting in unintended or uncontrollable movements.

Similarly, human studies also support these claims, indicating L-serine safety and tolerability. For example, the phase I trial involving 20 people with ALS (amyotrophic lateral sclerosis, or Lou Gehrig's Disease) revealed that oral L-serine intake appears to reduce disease progression. Similarly, L-serine might also be effective against schizophrenia and other neurodegenerative disorders, according to a 2021 study. Research on l-serine's protective role against Alzheimer's is ongoing, and the results seem promising. However, large clinical trials are needed to make objective claims.

Fibromyalgia And Fatigue Benefits

Fibromyalgia is a chronic condition that causes pain and tenderness throughout the body, accompanied by fatigue, sleep, memory, and mood issues. Research suggests that low serotonin levels in the body are associated with fibromyalgia syndrome. Fibromyalgia is also associated with an altered gut microbiome, which can cause mitochondrial dysfunction. Serotonin, also made in the gut, is one of the most critical neurotransmitters in the nervous system affecting mood, digestion, sleep, and more.

Serotonin requires tryptophan—an essential amino acid—for its synthesis. In addition, besides the tryptophan needed in food, your body can also make it from L-serine. Thus, increasing l-serine consumption may boost tryptophan synthesis and the subsequent production of serotonin, improving mood, sleep, and memory but may also help manage fibromyalgia symptoms per studies.

Sleep Benefits

Sleep deprivation remains a significant health concern in the united states, with data suggesting that one in three people in the USA and almost similar in other countries do not get enough sleep.

However, the good news is that L-serine consumption helps with sleep disturbances and improves quality. For instance, a 2014 Japanese study showed that l-serine intake before bed decreased "the number of nighttime awakenings" in the study group compared with the control group. Furthermore, another study showed that L-serine ingestion before bedtime regulates circadian rhythms and promotes a regular sleep-wake cycle.

Heart Health Benefits

Unfortunately, cardiovascular diseases have become the leading cause of death worldwide, including in the United States. Yet, only a tiny proportion of people become aware of their condition before they develop symptoms. As a result, taking preventive measures remains the most effective way to reduce the risk and enjoy healthy living. L-serine may have a protective role against cardiovascular diseases. For instance, a 2008 lab study showed that L-serine supplementation significantly reduces blood pressure by manipulating the conduction of nerve impulses in the heart and blood vessels.

Another study showed that L-serine has antioxidant properties and offers protective benefits for the endothelial cells — found in the inside lining of blood vessels, lymph vessels, and the heart. However, more research is needed before doctors recommend l-serine for heart disease prevention.

Blood Sugar Benefits

Obesity has become a worldwide pandemic, along with a steady rise in the incidence of diabetes. Research has linked diabetes to an altered serine metabolism in the body. As a result, l-serine supplementation may offer a new therapeutic way to improve glucose control, according to a 2018 animal study. Furthermore, l-serine consumption may also prevent diabetic complications, especially diabetic neuropathy—a type of neuronal damage caused by elevated blood sugar, according to studies.

Takeaway

Research has found l-serine to be safe and well-tolerated in human and animal studies. That being said, l-serine supplements may upset the stomach, cause bloating, or lead to constipation for some.

The best way to increase body levels of l-serine is by eating foods rich in this nutrient. However, if you want to go one step ahead, speak with your doctor or healthcare provider about starting supplementing with l-serine.

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