Soy Lecithin-Derived Phosphatidylserine Plus Phosphatidic Acid: Effects on Brain Functions in Elderly Patients with Alzheimer's Disease and Dementia

Abstract

Phosphatidic acid (PA) and phosphatidylserine (PS) and are natural constituents of healthy brain cell membranes, which have been recognized since the 1970s as essential to normal neuronal functioning. PA is a precursor in the formation of other phospholipids, including PS and phosphatidylethanolamine (PE). Also, it has an impact on membrane rigidity/flexibility, which is important in modulating exo-and endocytosis. PS is also an important precursor for PE synthesis. Since PS predominantly occurs in brain cells, but normal diets do not include the consumption of brains, PS is available to our brains mostly via natural "production" in our bodies.Here, we present a tabulated literature survey of clinical studies on PS and/or PA regarding brain function in elderly people. In addition we give a summary on two of our our already published pilot studies performed with a brain-health food supplement containing a proprietary blend of 100 mg PS and 80 mg PA produced from soy lecithin: A three-month double-blind, placebo-controlled study demonstrated the positive influence of three PS+PA capsules/ day, (300 mg PS+240 mg PA per day; n=40)) or placebo (n=32) on memory and mood in functioning, non-depressive elderly people with memory problems. In a two-month randomized, double-blind, placebo-controlled study, three PS+PA capsules/day (300 mg PS+240 mg PA per day; n=56) or placebo (n=40) improved daily functioning, mental health, emotional state, and self-reported general condition in patients with Alzheimer's disease (AD).Altogether there is encouraging clinical data that PS+PA supplementation could be beneficial to AD patients and other elderly people with memory or cognition problems. Long-term studies are, however, still lacking. Keywords: Phosphatidylserine (PS) and Phosphatidic Acid (PA) in MemoryThe membrane phospholipids phosphatidic acid (PA) and phosphatidylserine (PS) are essential to cellular functioning, acting as a biological detergent, keeping fatty substances soluble and cell membranes flexible [1,2]. During the pathogenesis of several age-related neurodegenerative diseases, including Alzheimer's disease, the neuronal membrane lipid composition is altered in the brain [3,4]. Also, the lipid raft composition appears to be altered in neurodegenerative diseases [5]. PS (and PA), produced by enzymatic conversion of soybean lecithin, avoids possible regulatory and safety issues regarding bovine spongiform encephalopathy. Soy lecithin-derived PS is absorbed and metabolized, with elevated serum levels for at least 1.5 hours after an oral dose, as has been shown within a kinetic study on 8 human volunteers. The baseline serum level of PS in relation to the level of total serum phospholipids was around 2%. 30 minutes after ingestion, it started to increase, peaking at 90 minutes after intake at around 4%, and returning to the basal level 180 minutes after intake [23].Recently, oral administration of phosphatidylcholine/phosphatidylethanolamine (PE) -transphosphatidylated PS has been shown to improve memory imp...