Serine
 

Serine Introduction

Serine is a nonessential amino acid that can be metabolized from either threonine or glycine. This production, however, requires substantial amounts of vitamin B3, vitamin B6, and folic acid. Serine was first isolated in 1865 from a silk protein (sericin), and its benefits to proper functioning in the human body are numerous and extremely beneficial.

Serine is an amino acid that is readily assimilated for use by the digestive system. After digestion, serine’s inclusion within phospholipids (fatty compounds) is paramount, as it is one of many important constituents found in cellular membranes. It is an integral component of “brain proteins and the protective myelin sheath that covers [fragile] nerve fibers.” [1] Serine also provides for the synthesis of creatine, and certain RNA and DNA nucleotides; specifically purines and pyrimidines.

Being a natural moisturizing agent, serine can be found in various skin creams and skin care preparations.

Serine Food Sources

Many foods that may cause allergic reactions contain serine. These include, but are no limited to; meats, dairy products, peanuts, wheat gluten, and soy products. Serving sizes below are based upon 100 grams of a given food source and are expressed in milligrams, representing the amount of serine contained.

Vegetables and Vegetable Products
mg/200Cal Food Name
2378 Seaweed, spirulina, raw
2068 Seaweed, spirulina, dried

Legumes and Legume Products
mg/200Cal Food Name
2719 Soy protein isolate
2054 Soy protein concentrate

Finfish and Shellfish Products
mg/200Cal Food Name
1795 Fish, tuna, light, canned in water, drained solids
1795 Fish, tuna, light, canned in water, without salt, drained solids
1783 Fish, cod, Pacific, cooked, dry heat
1782 Fish, pike, northern, cooked, dry heat
1781 Fish, cod, Pacific, raw
1776 Fish, dolphinfish, cooked, dry heat
1775 Fish, cod, Atlantic, cooked, dry heat

Poultry Products
mg/200Cal Food Name
1993 Turkey, fryer-roasters, light meat, meat only, raw
1981 Turkey, fryer-roasters, breast, meat only, cooked, roasted
1823 Turkey, all classes, light meat, raw
1814 Turkey, young hen, light meat, meat only, raw
1794 Quail, breast, meat only, raw

Pork Products
mg/200Cal Food Name
1781 Pork, fresh, variety meats and by-products, kidneys, cooked, braised

Lamb, Veal, and Game Products
mg/200Cal Food Name
1806 Game meat, elk, cooked, roasted

Sausages and Luncheon Meats
mg/200Cal Food Name
2141 Turkey, white, rotisserie, deli cut
1925 Turkey breast meat

Dairy and Egg Products
mg/200Cal Food Name
2929 Egg, white, dried
2280 Cheese, cottage, nonfat, uncreamed, dry, large or small curd
2098 Egg substitute, liquid
1931 Cheese, cottage, lowfat, 1% milkfat

[2]

Serine Uses

As previously stated, serine provides for a multitude of processes in the human body. Among the most important of these tasks is the production of antibodies and immunoglobulins. Immunoglobulins are soluble proteins that act as antibodies. They are found in body fluids and blood serum, and are dependant upon serine for their overall development and functioning.

In clinical study, serine supplementation assisted nearly sixty percent of all individuals suffering from Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS). [3] Although serine is present in all CFIDS patients, levels are usually abnormally low. Six patients were studied for a period of one month and received 500 milligrams of L-serine twice per day. After this treatment period, five patients saw dramatic improvements in energy production, digestive function, joint and muscle function, and improvements with ear, nose and throat problems. Serine deficiency may prove to be an important finding when evaluating the factors contributing to the onset of Chronic Fatigue.

Serine is also needed to produce sufficient amounts of the amino acid tryptophan. Tryptophan is known as a relaxant, stress reliever, and aid in thwarting anxiety and depression. Tryptophan’s role as a precursor, enabling the creation of serotonin, is often overlooked. Serine is not only vital in this conversionary process, it is equally fundamental in the manufacturing process of other critical neurotransmitters.

Individuals suffering from Fibromyalgia (FM) may also benefit from the additional supplementation of serine. Fibromyalgia is an increasingly recognized chronic pain- illness characterized by widespread musculoskeletal aches, pain and stiffness, soft tissue tenderness, general fatigue, and sleep disturbances. Clinical studies reveal decreased levels of serine (along with other amino acids) in patients suffering from FM. [3] Insufficient levels of serine also impact critical levels of both tryptophan and serotonin. Serine is a precursor to these neurotransmitters; both of which have been identified as deficient in persons suffering from this illness.

Serine Dosages

Because serine is considered a nonessential amino acid, a Recommended Daily Allowance has not been established. However, the U.S. National Academy of Sciences has recognized the importance of proper protein intake, recommending that healthy persons achieve .36 grams of highly bioavailable protein for each pound of bodyweight - equaling 0.8 grams of protein, per kilogram of bodyweight.

Serine Toxicities and Deficiencies

Serine Toxicities

A toxicity level for serine has not been established. Excessive and prolonged doses of serine may cause immune suppression, sleep disorder, and psychological symptoms as witnessed in cerebral allergies. Cerebral allergy is a term that defines a condition in individuals who have trouble concentrating, coupled with headaches as well as other complaints.

Serine Deficiencies

Signs and symptoms of a serine deficiency have not been reported in medical literature. However, deficiencies of nonessential amino acids will occur if protein intake is neglected.

Although inconclusive, studies suggest that serine deficiencies may be linked to Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS). [3] Abnormally low levels of serine are often found in patients suffering from CFIDS; these patients also exhibit an impairment of neurological function, decreased pain tolerance, and increases in severity of pain.

References

1. Balch, Phyllis A., James F. “Amino Acids.” Prescription for Nutritional Healing. Ed. Amy C. Tecklenberg. New York, NY: Penguin Putnam Inc., 3rd Ed. 2000. 42-53.

2. Nutrition Data. “999 Foods; Highest in Serine.” (2004) http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml

3. Addington, John W. “L-Serine: Treatment for CFIDS. Fibromyalgia & Chronic Fatigue Syndrome news and information. (2004) Prohealth, Inc. http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml

4. Zest for life information page. “RDA of amino acids.” (1999-2003) http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml (14 Sept. 2004).