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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Phosphatidylserine (abbreviated Ptd-L-Ser or PS) is a phospholipid component, usually kept on the inner-leaflet (the cytosolic side) of cell membranes by an enzyme called flippase. When a cell undergoes apoptosis, phosphatidylserine is no longer restricted to the cytosolic part of the membrane, but becomes exposed on the surface of the cell.
Possible health benefits
Memory and cognition
Early studies of phosphatidylserine distilled the chemical from bovine brain. Commercially available products are made from cabbage or soybeans, because of concerns about mad cow disease. The fatty acids attached to the serine in the plant-based products have a similar, but not identical, chemical structure, but without the risk of infection.
Although a preliminary study in rats indicated that the soy product was as effective as that of bovine origin in one of three behavioral tests, later clinical trials in humans found that "a daily supplement of S-PS (soybean derived PS) does not affect memory or other cognitive functions in older individuals with memory complaints."
On May 13, 2003, the U.S. Food and Drug Administration stated "based on its evaluation of the totality of the publicly available scientific evidence, the agency concludes that there is not significant scientific agreement among qualified experts that a relationship exists between phosphatidylserine and reduced risk of dementia or cognitive dysfunction." FDA also stated "of the 10 intervention studies that formed the basis of FDA's evaluation, all were seriously flawed or limited in their reliability in one or more ways." It concludes that "most of the evidence does not support a relationship between phosphatidylserine and reduced risk of dementia or cognitive dysfunction, and that the evidence that does support such a relationship is very limited and preliminary."
FDA gave "qualified health claim" status to phosphatidylserine, allowing labels stating that, "Consumption of phosphatidylserine may reduce the risk of dementia in the elderly" and "Consumption of phosphatidylserine may reduce the risk of cognitive dysfunction in the elderly," with the disclaimer that, "Very limited and preliminary scientific research suggests that phosphatidylserine may reduce the risk of cognitive dysfunction in the elderly. FDA concludes that there is little scientific evidence supporting this claim."
In athletes, PS has been shown to improve cognitive functioning[unreliable source?], performance[unreliable source?], endocrine response to stress[unreliable source?], decreased muscle damage[unreliable source?], and decreased soreness and improved well-being following exercise in athletes involved in cycling, weight training, golf and endurance running. PS has been reported to be an effective supplement for combating exercise-induced stress by blunting the exercise-induced increase in cortisol levels in a dose dependent manner. While 800 mg and 600 mg PS per day for 10 days successfully attenuates the increase in cortisol levels, a lower dose (400 mg) has failed to show this desired effect. PS supplementation promotes a desirable hormonal balance for athletes and might attenuate the physiological deterioration that accompanies overtraining and/or overstretching. In recent studies, PS has been shown to enhance mood in a cohort of young people during mental stress and to improve accuracy during tee-off by increasing the stress resistance of golfers.
Attention-deficit hyperactivity disorder
A follow-up study backed up previous findings. The study found children supplementing with 200 mg PS per day for two months saw a significant improvement in ADHD symptoms.
Traditionally, PS supplements were derived from bovine cortex (BC-PS); however, due to the potential transfer of infectious diseases, soy-derived PS (S-PS) has been established as a potential safe alternative. Soy-derived PS is Generally Recognized As Safe (GRAS) and is a safe nutritional supplement for older persons if taken up to a dosage of 200 mg three times daily.
PS can be found in meat, but is most abundant in the brain and in innards such as liver and kidney. Only small amounts of PS can be found in dairy products or in vegetables, with the exception of white beans.
Table 1. PS content in different foods.
|Food||PS Content in mg/100 g|
|Soy lecithin||5900 |
|Offal (average value)||305|
|Chicken leg, with skin, without bone||134|
|Chicken breast, with skin||85|
|Turkey leg, without skin or bone||50|
|Turkey breast without skin||45|
|Whole grain barley||20|
|European pilchard (sardine)||16|
|Cow's Milk (whole, 3.5% fat)||1|
The average daily PS intake from the diet in Western countries is estimated to be 130 mg.
Phosphatidylserine is biosynthesized in bacteria by condensing the amino acid serine with CDP (cytidine diphosphate)-activated phosphatidic acid. In mammals, phosphatidylserine is produced by base-exchange reactions with phosphatidylcholine and phosphatidylethanolamine. Conversely, phosphatidylserine can also give rise to phosphatidylethanolamine and phosphatidylcholine, although in animals the pathway to generate phosphatidylcholine from phosphatidylserine only operates in the liver.
Annexin-A5 is a naturally-occurring protein with avid binding affinity for PS. Labeled-annexin-A5 enables visualization of cells in the early- to mid-apoptotic state in vitro or in vivo. Another PS binding protein is Mfge8.
Technetium-labeled annexin-A5 enables distinction between malignant and benign tumours whose pathology includes a high rate of cell division and apoptosis in malignant compared with a low rate of apoptosis in benign tumors.
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- "Can phosphatidylserine improve memory and cognitive function in people with Alzheimer's disease?". mayoclinic.com. Retrieved 2013-03-17.
- Christine L. Taylor, Ph.D. (May 13, 2003). "Phosphatidylserine and Cognitive Dysfunction and Dementia (Qualified Health Claim: Final Decision Letter)". Office of Nutritional Products, Labeling and Dietary Supplements Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration. Retrieved 2014-01-20.
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- Fernholz KM, Seifert JG, Bacharach DW, Burke ER, Gazal O (2000). "The Effects of Phosphatidyl Serine on Markers of Muscular Stress in Endurance Runners [abstract]". Med Sci Sports Exerc 32 (4): S321.
- Fahey TD, Pearl MS (1998). "The Hormonal and Perceptive Effects of Phosphatidylserine Administration During Two Weeks of Weight Training-Induced Over-Training". Biol Sport 15 (2).
- Benton D, Donohoe RT, Sillance B, Nabb S (2001). "The Influence of phosphatidylserine supplementation on mood and heart rate when faced with an acute stressor". Nutr Neurosci 4 (3): 169–178. PMID 11842886.
- Hirayama S, Masuda Y, Rabeler R (September–October 2006). "Effect of phosphatidylserine administration on symptoms of attention-deficit/hyperactivity disorder in children". Agro Food 17 (5): 32–36.
- Vaisman N, Kaysar N, Zaruk-Adasha Y, Pelled D, Brichon G, Zwingelstein G, Bodennec J (2008). "Correlation between changes in blood fatty acid composition and visual sustained attention performance in children with inattention: effect of dietary n-3 fatty acids containing phospholipids". The American Journal of Clinical Nutrition 87 (5): 1170–1180. PMID 18469236.
- Hirayama S., Terasawa K., Rabeler R., Hirayama T., Inoue T., Tatsumi Y., Purpura M. & Jäger R. (2013). "The effect of phosphatidylserine administration on memory and symptoms of attention-deficit hyperactivity disorder: a randomised, double-blind, placebo-controlled clinical trial". Human Nutrition and Dietetics. doi:10.1111/jhn.12090. PMID 23495677.
- Jorissen BL, Brouns F, Van Boxtel MP, Riedel WJ (October 2002). "Safety of soy-derived phosphatidylserine in elderly people". Nutr Neurosci 5 (5): 337–343. doi:10.1080/1028415021000033802. PMID 12385596.
- Souci SW, Fachmann E, Kraut H (2008). Food Composition and Nutrition Tables. Medpharm Scientific Publishers Stuttgart.
- C.R. Scholfield (October 1981). "Composition of Soybean Lecithin". Journal of the American Oil Chemists' Society 58 (10): 890.
- Phosphatidylserine and related lipids
- "Phosphatidylcholine, structure, occurrence, biochemistry and analysis". Lipidlibrary.aocs.org. 2012-04-30. Retrieved 2012-08-06.
- DrugBank info page
- FDA Qualified Health Claim Phosphatidylserine and Cognitive Dysfunction and Dementia
- Phosphatidylserines at the US National Library of Medicine Medical Subject Headings (MeSH)