Plasmalogens, Part 2

This post compares Dr. Goodenowe’s clinical trial mentioned in Part 1 with other researchers’ human plasmalogen studies this decade. One of its findings was:

“Figure 1A illustrates that plasmalogen precursor DHA-AAG dose-dependently elevated both direct and indirect target species [DHA-PL, DHA-PE, and (LA + AA)-PL] and had no effect on levels of biochemically unrelated PE species index (LA + AA)-PE.

DHA-AAG had a greater elevating effect on its direct target, DHA-PL than its indirect targets.

The 1-month washout period resulted in decreased levels of both direct and indirect target species and no effect on unrelated PE species.

Figures 1A,B illustrate that DHA-AAG is converted to its direct and indirect target species in humans as predicted from animal studies on similar AAG plasmalogen precursors (Wood et al., 2011d).”

Given this century’s background of numerous animal studies, there’s a need to know what translates to humans. Here are the three most recent human plasmalogen studies in descending order where I could access the full study:

2022

“Forty unmarried male students aged 18–22 years (20 in the plasmalogen group and 20 in the placebo group) were randomly allocated to either plasmalogen (2 mg per day) or placebo treatment of 4 weeks’ duration and ingested two capsules of 0.5 mg plasmalogen or placebo twice daily.

The primary efficacy outcome was the Total Mood Disturbance (TMD) T-score of POMS 2–Adult Short.

Secondary outcomes included the seven individual scales of POMS 2, other psychobehavioral measures (Athens Insomnia Scale and Uchida-Kraepelin test), physical performance test (shuttle run, grip muscle strength, and standing long jump), plasmalogen levels in plasma and erythrocytes, plasma levels of brain-derived neurotrophic factor (BDNF), urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), body mass index, and percent body fat.

Lipid composition of purified ether phospholipids from scallop is shown below. One capsule contained 0.48 mg of ethanolamine plasmalogen and 0.02 mg of choline plasmalogen. Plasmalogen and placebo capsules were prepared by a manufacturer (B&S Corporation, Tokyo).

There were no between-group differences in physical and laboratory measurements. It is suggested that orally administered plasmalogens alleviate negative mood states and sleep problems, and also enhance mental concentration.”

https://www.frontiersin.org/articles/10.3389/fcell.2022.894734/full “Orally Administered Plasmalogens Alleviate Negative Mood States and Enhance Mental Concentration: A Randomized, Double-Blind, Placebo-Controlled Trial”

There was no dose / response investigation, so there’s no data to corroborate that this 2 mg treatment produced these effects. It isn’t difficult to think of other factors that could influence the primary outcome of a 18-22 year-old unmarried male’s moods.

2020

“Effects of ascidian-derived plasmalogens on cognitive performance improvement were assessed in a randomized, double-blind, placebo-controlled study including Japanese adult volunteers age 45.6 ± 11.1 years with mild forgetfulness. An allocation controller who was not directly involved in the study equally, but randomly, assigned participants to either the intervention group (n＝33) or the placebo group (n＝33), based on normalized Cognitrax composite memory score (the primary outcome), sex, and age at time of screen. Participants were administered either one active capsule (200 mg medium-chain triglyceride (MCT) oil including ascidian plasmalogen oil) or placebo capsule (200 mg MCT oil) per day with water, any time during the day for 12 weeks.

Ascidian plasmalogen oil was extracted from ascidians (Halocynthia roretzi) and sold by NIHON PHARMACEUTICAL CO., LTD. Based on a previous study, 33％ of lipids contained in ascidians are phospholipids, 23％ of which are plasmalogens, and fatty acids of the sn-2 position of plasmalogens are mainly EPA, DHA, oleic acid, and arachidonic acid. The active capsule contains 1 mg plasmalogen.

Compared to the placebo group, the intervention group showed a significant increase score in composite memory (eight weeks: 3.0 ± 16.3 points, 12 weeks: 6.7 ± 17.5 points), which was defined as the sum of verbal and visual memory scores. These results indicate consumption of ascidian-derived plasmalogen maintains and enhances memory function.”

https://www.jstage.jst.go.jp/article/jos/69/12/69_ess20167/_article “The Impact of Ascidian (Halocynthia roretzi)-derived Plasmalogen on Cognitive Function in Healthy Humans: A Randomized, Double-blind, Placebo-controlled Trial”

Again no dose / response investigation, so no corroborating data. Standard deviations many times larger than a sample’s mean indicated wild variability (aka noise). Maybe intervention participants experienced memory loss (3.0 mean – 16.3 SD = -13.3; 6.7 mean – 17.5 SD = -10.8)? Yet statistics inferred a signal that allowed interpreting this treatment as producing meaningful positive changes in cognitive function.

“Ten Parkinson’s disease (PD) patients age 67.80 (7.41) years received oral administration of 1 mg/day of purified ether phospholipids derived from scallop for 24 weeks. Clinical symptoms and blood tests were checked at 0, 4, 12, 24, and 28 weeks. Blood levels of plasmalogens in patients with PD were compared with those of 39 age-matched normal controls.

B&S Corporation Co. Ltd. (Tokyo) was involved in provision of capsules containing ether phospholipids derived from scallop. Ethanolamine ether phospholipids (ePE) in plasma from PD and relative composition of ethanolamine plasmalogen (plsPE) of erythrocyte membrane in PD were significantly low as compared to those of age-matched normal controls.

Oral administration of purified ether phospholipids derived from scallop for 24 weeks increased plasma ePE and erythrocyte plsPE to almost normal levels, and concomitantly improved some clinical symptoms of patients with PD. Results indicate the efficacy of oral administration of purified ether phospholipids derived from scallop to some nonmotor symptoms of PD. Physiological mechanisms of the efficacy of purified ether phospholipid derived from scallop remained to be elucidated.”

https://www.hindawi.com/journals/pd/2020/2671070/ “Improvement of Blood Plasmalogens and Clinical Symptoms in Parkinson’s Disease by Oral Administration of Ether Phospholipids: A Preliminary Report

Again no dose / response investigation, so no corroborating data. These researchers asserted their 2017 study to be a plasmalogen gold standard, as did the other two above studies.

Here’s part of what Dr. Goodenowe said about that 2017 study in a 2019 review Plasmalogen deficiency and neuropathology in Alzheimer’s disease: Causation or coincidence?:

“They did not observe a significant elevation of plasma levels of plasmalogens in the treated group relative to the baseline. Lower dose of plasmalogens (1 mg twice daily) and the labile nature of the vinyl-ether bond might have limited absorption of the intact molecule and might have contributed to the lack of response in terms of plasmalogen levels in blood as well as the cognitive function. Reported instability of plasmalogens in acidic environments questions the stability of preformed plasmalogens in gastric juice during digestion which might reduce plasmalogen bioavailability.”

Also see Part 1’s explanation of why using age-matched controls in plasmalogen studies is ridiculous.

Continued in Part 3.