Aging often becomes visible in familiar ways, from gray hair and wrinkles to memory lapses. This has fueled a long-standing scientific question: Could some of those changes eventually be slowed, prevented, or even reversed?
Research involving a group of scientists from Xi’an Jiaotong-Liverpool University, Stanford University, Shanghai Jiao Tong University and the University of the Chinese Academy of Sciences points to an intriguing possibility. In experiments with aged mice, researchers found that dietary supplements containing compounds associated with Ascidiacea, commonly known as sea squirt, reversed several signs related to aging.
An unusual source of anti-aging compounds
Sea squirts are marine animals eaten in parts of Asia, including Korea (where they are known as meonggeor 멍게) and Japan (hoyaor ホヤ). They can be eaten raw and contain high levels of compounds called plasmalogens.
Plasmalogens are a type of lipid or fat molecule that forms an important part of cell membranes. They are found naturally throughout the human body and are especially abundant in the brain, heart, and immune cells. Its levels tend to decrease as people age.
Reduced levels of plasmalogen have also been observed in several neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. That connection has led researchers to investigate whether restoring plasmalogens could help protect the brain from some of the changes associated with aging.
To explore that possibility, the team added plasmalogens to the diets of elderly mice and examined how the supplements affected both their behavior and their bodies.
The results were surprising. The treated mice showed substantial improvements in learning and also showed visible physical changes.
Professor Lei Fu, corresponding author of the study, says: “Our research suggests that plasmalogens may not only stop cognitive decline, but may reverse cognitive declines in the aging brain. Furthermore, elderly mice fed plasmalogens grow new black hair that is thicker and shinier than elderly mice that did not receive the supplement.”
According to the researchers, the work provides the first detailed insight into how plasmalogens may influence brain aging.
Aging Mice Show Improved Memory
To measure learning and memory, scientists used a common laboratory experiment called the Morris water maze. In this test, mice are placed in a pool that contains a hidden platform where they can rest.
Since mice generally prefer to escape from the water, they gradually learn where the platform is located. After several days of training, younger mice usually remember their position and swim toward it quickly. Older mice typically take longer to locate the platform, reflecting the decline in learning and memory that can accompany aging.
After five days of training, the elderly mice given plasmalogens behaved much more like the younger animals. They reached the platform significantly faster than older mice that had not received the supplement.
The researchers then examined the animals’ brains to determine what could explain the improvement.
They found that mice given plasmalogens had more synapses, and those synapses appeared to be in better condition than those in untreated aged mice.
Synapses are the small junctions through which nerve cells communicate. They allow signals to pass through neural networks and are essential for learning, memory and many other brain functions.
Restore connections in the aging brain
Synapses are very adaptable in the early stages of life. This ability to change and form new connections, often called neural plasticity, helps the brain learn new information and skills.
However, with age, synapses may become less numerous and less effective. Similar impairment is also associated with neurodegenerative diseases and may contribute to decreased cognitive abilities.
In the experiment, aged mice given plasmalogen supplements appeared better able to form new neural connections and learn new tasks than mice on a normal diet. The findings suggest that increasing plasmalogens in the diet may help protect synapses from some forms of age-related decline.
The researchers also identified another important difference between the groups: Inflammation in the brain was substantially lower among the mice given plasmalogens.
Inflammation is part of the body’s normal immune response, but chronic or excessive inflammation in the brain can become harmful. As the brain ages, immune activity can become dysregulated, potentially damaging nerve cells and disrupting communication between synapses. Persistent inflammation is also considered a major contributor to several neurodegenerative disorders.
Therefore, the reduction in inflammation seen in the plasmalogen-treated mice could help explain why they performed better on learning and memory tests.
How plasmalogens might work
Scientists still don’t know exactly how dietary plasmalogens produce these effects. Professor Fu described several possible mechanisms.
“We found that plasmalogens significantly increase the number of molecules that help the growth and development of neurons and synapses in the brain. This suggests that plasmalogens may promote neuroregeneration.
“There is also increasing evidence that plasmalogens directly affect the structural properties of synapses. Plasmalogens may increase the fluidity and flexibility of synaptic membranes, affecting the transmission of impulses between neurons.”
Neuroregeneration refers to the repair, renewal or growth of nerve cells and their connections. If plasmalogens support that process, they could help the aging brain maintain or rebuild some of the neural circuits needed for memory and learning.
Researchers also believe that the effects may not be limited to what happens directly inside the brain.
Professor Fu points to the gut-brain connection as another possible pathway.
“Some studies have shown that dietary plasmalogens affect microorganisms in the gut. It has been widely reported that the connection between organisms in our gut and our brain influences neurodegeneration. It may be the effect of plasmalogen on this connection that causes the improvements in learning and memory observed in this study.”
The gut contains huge communities of bacteria and other microorganisms, collectively known as the gut microbiome. Research increasingly suggests that these microbes can influence the brain through immune signaling, metabolism, and other biological pathways. Scientists often refer to this two-way communication system as the gut-brain axis.
Could plasmalogens eventually help people?
Professor Fu is so confident in the results that he personally takes a plasmalogen supplement every day.
“For the first time, we show that plasmalogen supplements could be a possible intervention strategy to stop neurodegeneration and promote neuroregeneration.
“Oral intake of plasmalogens could be a viable therapeutic strategy to improve cognitive function in older people.”
The findings are intriguing, but they come from an animal model. The improvements seen in mice do not necessarily mean that eating sea squirts or taking plasmalogen supplements will reverse aging in humans. Additional research would be needed to determine whether similar effects occur in people, what doses might be effective, and whether long-term supplementation is safe.
Still, the results raise an unusual possibility. A compound found in an edible marine animal may offer scientists a new way to investigate how aging affects the brain and whether some of those changes can eventually be reversed.