Written by Angeline A. De Leon, Staff Writer. Of the study participants with mild Alzheimers, those who supplemented with a scallop-derived plasmalogen significantly improved their memory compared to the control group. Also significant was the memory improvement in a subgroup of participating females and those who were younger than 77 years of age.
Plasmalogens (PIs) are an important structural component of cell membranes, present in all types of human tissue and most abundantly found in the brain. These phosophlipids (fatty tissue layers) are involved in many essential brain functions, including membrane fusion, ion transport, and antioxidant activity 1.
PI levels decline with age, and research suggests that Alzheimer’s Disease (AD) may be associated with decreased levels of a specific PI, phosphatidyl ethanolamine Pls (PIsPE). Patients with AD, for example, show reduced concentrations of PIsPE in their blood and cerebrospinal fluid 2,3 as well as key brain areas such as the frontal cortex and hippocampus 4,5. However, promising evidence from animal studies indicates that cognitive functioning may be improved by the administration of purified PIs 6. To examine this effect in humans at risk for cognitive impairment, a 2017 study by Japanese researchers evaluated whether oral intake of PIs extracted from scallops (a food source highly rich in PI) would benefit the cognitive health of individuals with mild AD and mild cognitive impairment (MCI).
A multicenter, randomized, double-blind, placebo-controlled trial was conducted in the span of 24 weeks, involving a total of 276 patients (ages 60-85) who qualified for mild AD and MCI. Diagnosis was based on performance on the Japanese Versions of the Mini Mental State Examination (MMSE-J) and Short-Version Geriatric Depression Scale (GDS-S-J). At baseline, Week 12, and Week 24, patients were assessed on cognitive function (using the MMSE-J and the Revised Wechsler Memory Test, WMS-R). Plasma concentrations of PIsPE in the red blood cell membrane and plasma were analyzed from blood samples. During the trial period, participants were randomly assigned to orally consume 1.0 mg of either PIs (n = 140) or a placebo (n = 136) daily for 24 weeks.
At the end of the trial, researchers found no significant overall difference between treatment and placebo groups on cognitive function and plasma levels of PIs. However, patients in the PI treatment group who had mild AD showed significant improvement on the memory test, with the difference between treatment and placebo groups approaching significance (p = 0.067). A subgroup analysis of mild AD patients also revealed that working memory scores were significantly improved among those in the treatment group who were female (between-group difference statistically significant at p = 0.017) and younger than 77 years of age (between-group difference statistically significant at p = 0.029). Furthermore, patients with mild AD in the placebo group showed significantly greater reductions in plasma levels of PIsPE than the treatment group (between-group difference statistically significant at p = 0.016).
Overall, findings demonstrate the efficacy of using scallop-derived purified PIs to support cognitive health, particularly memory function, in patients with mild AD. Dietary supplementation with PI-rich foods may be useful in rebalancing PI levels in older adults with cognitive impairment. However, the unexplained differential efficacy of PIs in females vs. males and the failure to produce any significant changes in patients with MCI are critical points that deserve further investigation.
Source: Fujino T, Yamada T. Asada T. et al. Efficacy and blood plasmalogen changes by oral administration of plasmalogen in patients with mild alzheimer’s disease and mild cognitive impairment: A multicenter randomized double-blind placebo-controlled trial. EBioMedicine. 2017; 17: 199-205.
© 2017 The Authors. Published by Elsevier B.V. CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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Posted April 24, 2017.
Angeline A. De Leon, M.A., graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program.
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