Phosphatidylserine May Treat Aging Memory Loss

A Dietary Supplement Shows Promise in Reducing Cognitive Impairment

Jun 29, 2009

A supplement, called phosphatidylserine (PS), has been reported to reduce age-related cognitive decline. What is the evidence supporting this claim?

A number of studies in aging laboratory animals have shown that PS prevents loss of neurons, improves performance on some memory tests, and preserves dendritic spine density in the areas of the brain associated with memory.

If PS is Effective, How Might it Work?

A clue as to PS's role in preventing cognitive decline came from research published in 1998 in which the authors concluded: “Phosphatidylserine is a phospholipid that is part of the cell membrane, is most concentrated in brain tissue, and participates in activation of the protein kinase C (PKC) enzyme complex”. (Vinton BB, Wertz SL, Jaison J, Steere J, Grisham CM, David S. Cafiso DS, and JJ Sando, 1998. Biochem. J. 330,1433-1442). The important clue is that PS participates in activating the PKC enzyme complex, and the importance derives from the fact that the PKC enzyme complex's role in neurons is that of a second messenger. “Second messenger” is biochem speak for a series of chemicals that executes the “instructions” given by the neurotransmitter. (In a computer analogy, the neurotransmitter would be the keys struck by the user, and the second messenger would be the operating system that carries out the instructions.) Perhaps PKC's second-messenger role is the reason that The Alternative Medicine Review states: “PKC dysfunction is one of the earliest changes noted in AD [Alzheimers Disease]”. Kidd, P.M. 2008. Alternative Medicine Review 13;2).

Have human clinical studies validated PS's effectiveness in preventing cognitive decline? Yes and no.

Human Clinical Trials Measuring PS Effectiveness in Preventing/Treating Cognitive Impairment

Two studies have demonstrated that PS had a statistically significant effect on improving behavioral and cognitive activity:

The study participants received placebo for 15 days and received bovine-PS (300 mg/day) for the following 30 days. The study authors evaluated the participant's symptoms by the following measurements: the Hamilton Rating Scale for Depression, the Gottfries-Bråne-Steen Rating Scale, the Nurse's Observation Scale for Inpatient Evaluation, and the Buschke Selective Reminding Test, and the series of tests were performed before placebo, after placebo, and after bovine-PS therapy. The authors reported that “bovine-PS induced consistent improvement of depressive symptoms, memory and behavior.” (Maggioni M, Picotti GB, Bondiolotti GP, Panerai A, Cenacchi T, Nobile P and F Brambilla. 1990. “Effects of phosphatidylserine therapy in geriatric patients with depressive disorders”. Acta Psychiatr Scand. Mar;81(3):265-70.)

The authors reported that “Statistically significant improvements in the PS-treated group compared to placebo were observed both in terms of behavioral and cognitive parameters. In addition, clinical evaluation and laboratory tests demonstrated that BC-PS was well tolerated.” (Cenacchi T, Bertoldin T, Farina C, Fiori MG and G Crepaldi. 1993. “Cognitive decline in the elderly: a double-blind, placebo-controlled multicenter study on efficacy of phosphatidylserine administration”. Aging (Milano). Apr;5(2):123-33.)

One-third of the subjects received placebo; one-third received 300 mg/day of soy-derived PS, and one-third received 600 mg/day soy-derived PS. The study authors evaluated the participant's learning, memory, choice reaction time, planning, and attentional functions at the beginning of the study, after 6 and 12 weeks of treatment, and after a wash-out period of 3 weeks.

The authors concluded: “No significant differences were found in any of the outcome variables between the treatment groups.” (Jorissen BL, Brouns F, Van Boxtel MP, Ponds RW, Verhey FR, Jolles J and WJ Riedel. 2001. “The influence of soy-derived phosphatidylserine on cognition in age-associated memory impairment”. Nutr Neurosci. 4(2):121-34.)

Difficulties in Evaluating the Evidence

Evaluating the role of PS in reducing/retarding cognitive impairment is complicated by the consideration that cognitive decline can have many causes. The United States National Institute of Neurological Disorders and Stroke states that "reactions to medications, metabolic problems and endocrine abnormalities, nutritional deficiencies, infections, poisoning, brain tumors, anoxia or hypoxia (conditions in which the brain's oxygen supply is either reduced or cut off entirely, and heart and lung problems" can cause dementia or dementia-like symptoms.

The possibility exists that PS may be more effective in treating cognitive impairment from some causes and less effective in treating impairment due to other causes. Human clinical trials have not yet separated out subjects by impairment etiology.

An additional difficulty in forming conclusions from the three described human clinical trials arises from the fact that the studies which found PS effective used bovine-PS (PS derived from cattle brains) and the study that found PS non-effective used soy-derived PS. Due to the concern about bovine spongiform encephalopathy (commonly known as mad-cow disease), which came into focus in the early 1990s, researchers have been unwilling to use bovine-derived PS.

The copyright of the article Phosphatidylserine May Treat Aging Memory Loss in Seniors' Health/Medicare is owned by Connie Stewart. Permission to republish Phosphatidylserine May Treat Aging Memory Loss in print or online must be granted by the author in writing.