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L-Serine: An Amino Acid Critical for Brain Health

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L-Serine - Dr. Axe

L-serine metabolism is critical for survival. We depend on this important amino acid for proper brain development, and it plays a critical role in the synthesis of proteins, neurotransmitters, nucleotides and lipids.

What does serine do? Research exploring the unique longevity of Ogimi villagers in Japan suggest that the amino acid helps you to live longer. The Ogimi people, whose average life expectancy exceeds 85 years for women, consume extraordinarily high amounts of L-serine, with seaweeds and tofu staples in their diets.

Researchers believe that the high content of this amino acid in the diet may offer neuroprotection and contribute to their neurological health in this community.

In addition to its potential cognitive effects, serine benefits include its ability to boost immune function, promote regular sleep and fight chronic fatigue syndrome. Although we make it in our bodies, which is why it’s considered a nonessential amino acid like alanine and others, most of us can benefit from eating foods high in this amino acid to ensure we get enough of this very important molecule.

What Is L-Serine? Role in Body

Serine is an amino acid that plays a role in many biosynthetic pathways. It’s the major source of one-carbon units for methylation reactions that occur with the generation of S-adenosylmethionine. It is also a precursor to a number of important amino acids, including cysteine and glycine.

It is recognized as a nonessential amino acid because it’s produced in the body, but we need to ingest foods high in this amino acid in order to maintain necessary levels for optimal health. It has actually become known as a “conditional non-essential amino acid” because, under certain circumstances, humans cannot synthesize it in quantities high enough to meet necessary cellular demands.

Amino acids form our living cells and the antibodies that make up our immune systems. They make up proteins that are crucial for our existence, and they are needed to carry oxygen throughout our bodies.

Serine, in particular, plays an important role in brain function and the health of the central nervous system. One of the many benefits of serine is its function in the formation of phospholipids that are needed for creating every single cell in the human body.

It plays a critical role in protein synthesis and intracellular metabolism, and it’s also involved in the functioning of RNA, DNA, immune function and muscle formation.

Serine is needed for the production of tryptophan, an essential amino acid that’s used to make serotonin. It is also converted into D-serine in the cells of the nervous system.

D-serine is known to boost cognitive health. It’s a “dextro isomer of L-serine,” and the two molecules mirror image each other.

D-serine activates NMDA receptors in the brain that work as neurotransmitters. Research shows that it may work as a therapeutic agent for schizophrenia, depression and cognitive dysfunction.

Benefits

1. Improves Brain Function

Research shows that L-serine is neuroprotective and acts through a variety of biochemical and molecular mechanisms to support brain function. It plays a vital role in the synthesis of phosphatidylserine, a component of neurons in the brain, and it’s known to have a critical role as a neuromodulator in the brain.

When looking at serine vs. phosphatidylserine, L-serine is essential for the synthesis of phosphatidylserine, a type of lipid. Phosphatidylserine is taken to improve memory and boost brain powder. This is why taking L-serine for dementia, Parkinson’s and Alzheimer’s is popular.

An article published in Pharmacy Times indicates that people with an environmental or possibly genetic risk of neurodegenerative disease may benefit from using L-serine supplementation.

2. Fights Fibromyalgia

Research suggests that some people struggling with fibromyalgia may have a serine deficiency, which alters the body’s ability to make tryptophan and serotonin. One study published in Biochemical and Molecular Medicine found that when patients with chronic fatigue syndrome had their urine tested and compared to controls, patients had serine levels that were significantly reduced.

3. Helps Relieve Stress

Serine is needed to produce the amino acid tryptophan, which serves as a natural stress reliever and relaxant. Increased tryptophan helps ease anxiety and symptoms of depression, as it’s used to make serotonin, a calming chemical that occurs naturally within the body.

Research published in Nutritional Neuroscience found that tryptophan can improve therapeutics in stress-induced hormonal and behavioral disorders. There is a proven role of serum serotonin levels impacting mental health status.

Because serine is crucial for the production of tryptophan and serotonin, maintaining normal levels may help relieve symptoms of stress.

4. Improves Sleep

Studies conducted in Japan found that taking L-serine before going to bed may improve human sleep. When participants who were dissatisfied with their sleep were given the amino acid or a placebo 30 minutes before bedtime, scores for “sleep initiation” and “sleep maintenance” improved significantly in the treatment group.

In another study, participants taking this amino acid for sleep expressed significant improvements when asked, “How well did you sleep last night?” and, “How satisfied were you with last night’s sleep?”

5. Fights Cancer

Research published in the Journal of Cell Biology shows that active serine synthesis is likely required to “facilitate amino acid transport, nucleotide synthesis, folate metabolism and homeostasis in a manner that impacts cancer.” Studies show that altered serine metabolism plays a role in cancer.

L-serine metabolism is needed to maintain homeostasis because it fuels processes that our cells need to oxidize nutrients and product energy in the form of ATP. Researchers suggest that an increase in availability of this amino acid could be valuable for proliferating cancer cells for multiple reasons, including the fact that the amino acid is critical for the biosynthesis of many macromolecules that play a role in fighting cancer growth.

6. May Fight Type 1 Diabetes

An animal study published in Plus One found that continuous supplementation of this amino acid reduced type 1 diabetes incidence and insulitis scores in mice. L-serine supplements also reduced blood glucose levels and caused a small reduction in body weight.

This data suggests that serine supplements may have an effect on autoimmune diabetes development.

7. Boosts Immune Function

Amino acids are needed for the regulation of the body’s immune system. Serine plays a role in the production of immunoglobulins and antibodies that are used by the immune system.

Related: Threonine: The Amino Acid Needed for Collagen Production

Foods High in L-Serine

When we eat serine foods, the molecule is extracted in the small intestine and then absorbed into circulation. It’s then able to travel through the body and cross the blood-brain barrier, where it enters your neurons and is metabolized into glycine and many other molecules.

Some of the foods highest in this amino acid include the following:

  1. Soybeans
  2. Peanuts
  3. Almonds
  4. Walnuts
  5. Pistachios
  6. Sweet potatoes
  7. Eggs
  8. Dairy products
  9. Grass-fed beef
  10. Chicken
  11. Turkey
  12. Lamb
  13. Wild fish
  14. Seaweed (spirulina)
  15. Lentils
  16. Lima beans
  17. Chickpeas
  18. Kidney beans
  19. Hemp seeds
  20. Pumpkin seeds

When we don’t eat enough foods high in this amino acid, more of the molecule is converted from other sources. When we ingest too much of the amino acid, only a portion is converted into glycine, and the remainder is metabolized into folate and other proteins.

Safety and Side Effects

The FDA has determined that L-serine is generally regarded as safe, and studies support this classification. Some possible side effects of L-serine include upset stomach, constipation, diarrhea and frequent urination.

A study published in Cold Spring Harbor Molecular Case Studies evaluated the safety profile and metabolic effects of L-serine supplements. One patient underwent a 52-week treatment in which the L-serine dose was increased up to 400 milligrams per kilogram a day (mg/kg/day).

The patient was followed up by repeated clinical exams, nerve conduction tests and skin biopsies to document the effects on small nerve fibers. Results showed a modest elevation in glycine levels and a reduction of cytosine levels.

There were no direct L-serine supplement side effects from the treatment. Researchers concluded that there were no major effects on metabolism from the treatment.

Supplement and Dosage Recommendations

L-serine is available as a dietary supplement in capsule and powder forms. You can also find L-serine gummies and brain supplements that are made with the molecule on the market.

Most supplements come in 500-milligram capsules, and the appropriate L-serine dosage depends on your health condition.

The average dietary intake of serine among adults living in the U.S. is about 2.5 grams per day. That’s actually way less than the eight grams per day that’s consumed by Ogimi women, mentioned earlier for their unique longevity.

Keep in mind that in order to naturally produce enough of this amino acid, the human body needs sufficient amounts of Vitamin B and folic acid. Combining L-serine foods or supplements with folic acid foods, like beef liver, spinach, avocado, broccoli and Brussels sprouts, can help increase serine levels.

Related: N-Acetylcysteine: Top 7 NAC Supplement Benefits + How to Use It

How to Use It

The most effective way to increase serine amino acid levels is to eat foods that are naturally high in the molecule. L-serine sweet potato, organic soy products, seaweed, nuts and eggs are just some of the best foods to increase or maintain adequate levels.

For people with significantly reduced levels of the amino acid or those looking to improve disease symptoms under the care of their doctors, taking a supplement may be effective. The common dose is one 500-milligram dose per day.

Before taking more than the standard dose, consult your health care professional.

Precautions

Patients using L-serine supplements to improve medical conditions, like chronic fatigue syndrome or neurodegenerative disease, should do so under the care of their health care professionals.

There is not enough research to recommend serine supplements during pregnancy or while nursing. Before taking the amino acid in these circumstances, consult your health care professional.

Final Thoughts

  • Is serine essential or nonessential? It’s a nonessential amino acid that plays a role in many biosynthetic pathways.
  • Although its produced naturally by the body, eating foods high in it can have beneficial effects.
  • What causes low serine? Although the body makes this amino acid, it may not make enough or you may not have enough folic acid to support the production of it.
  • Some of the best foods sources include seaweed, soy products, meats, nuts, beans and dairy foods.
  • Research shows that for people with low levels of the amino acid, using supplements may help improve brain health, immune function and mental health.
  • L-serine for ALS and other neurodegenerative diseases may also be beneficial.
  • Before taking more than the standard 500-milligram dose of this amino acid, consult your doctor or health care professional.

Read Next: L-Lysine Benefits the Gut, Brain and Herpes Outbreaks

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