Ascidians, commonly known as sea squirts, are sessile marine invertebrates belonging to the subphylum Tunicata, with fossil records tracing their origins back over 500 million years. These small, sac-like organisms typically anchor to rocks, piers, or coral reefs and display a leathery outer “tunic” that encloses a simple body with two siphons one for drawing in nutrient-rich seawater and another for expelling filtered water. Ranging in size from a few millimeters to several centimeters, their translucent or brightly colored bodies often appear as clusters, sponges, or bulbous bags. In health and wellness, ascidians have garnered interest for their bioactive compounds, including peptides and alkaloids with antioxidant, anti-inflammatory, and even anticancer potential, making them promising candidates for nutraceutical research and novel drug development.
Nutritional Composition of Ascidians
Ascidians, commonly known as sea squirts, represent a unique and nutritionally distinctive marine delicacy with an exceptionally low caloric profile at just 20 calories per 100-gram serving. This traditional Alaska Native food is remarkably lean, consisting of over 90% water content, while providing a modest but quality source of protein at 3.8 grams per serving. What makes ascidians particularly noteworthy from a nutritional standpoint is their impressive iron content, delivering 18% of the daily value, alongside a significant riboflavin contribution. However, individuals monitoring sodium intake should note the relatively high sodium content at 656 milligrams per serving, representing 29% of the recommended daily value. With virtually no carbohydrates and minimal fat content, ascidians offer a unique nutritional profile that appeals to those seeking low-calorie, protein-containing marine foods with notable mineral benefits.
Serving Size: 100 g
Target Audience: Individuals interested in overall health and wellness
| Nutrient | Amount per 100 g | % Daily Value* |
| Calories | 20 Kcal. | 1% |
| Water | 90.4 g. | N/A |
| Protein | 3.8 g. | 8% |
| Total Fat | 0.5 g. | 1% |
| – Saturated Fat | 0.1 g | 1% |
| – Monounsaturated Fat | 0.12 g | N/A |
| – Polyunsaturated Fat | 0.2 g | N/A |
| Cholesterol | 7mg | 2% |
| Ash | 3.1g | N/A |
| Calcium | 47mg | 4% |
| Iron | 3.3mg | 18% |
| Potassium | 102mg | 2% |
| Sodium | 656mg | 29% |
| Riboflavin (Vitamin B2) | 0.2mg | 15% |
Source: (1)
Science Backed Health Benefits of Ascidians Sea Squirts
1. Boosts memory and protects the brain
Remarkably, ascidians harbor a unique phospholipid called plasmalogen that supports healthy memory performance by maintaining neuronal membrane integrity and facilitating cellular signaling. (2) Additionally, these sea squirts contain bioactive terpenoids and unsaturated fatty acids, including DHA and EPA, which exhibit antioxidant and neuroprotective properties that help neutralize harmful free radicals in the brain. (3) (4) Importantly, research demonstrates that ascidian-derived plasmalogen is efficiently processed in a chordate model system, mimicking human APP metabolism pathways without requiring external secretase enzymes, thus underscoring its compatibility with human neurobiology. (5) (6) Beyond preserving synaptic function, ascidian bioactives have been shown to reduce neuroinflammation by modulating microglial activity, thereby protecting neural tissue from chronic inflammatory damage. (3) Clinical studies in healthy volunteers indicate that daily supplementation with ascidian-derived plasmalogen helps sustain composite memory scores over time, suggesting its role in cognitive maintenance. (2) Collectively, these findings highlight the promise of ascidian nutrients particularly plasmalogen, DHA, and EPA as natural support for memory enhancement and brain resilience.
2. Fights cancer cells
Remarkably, sea squirts, known as ascidians, produce powerful bioactive compounds that can help stop the growth of cancer cells. These small marine animals create unique alkaloids and cyclic peptides that interfere with tumor survival pathways. For example, the compound trabectedin, originally isolated from an ascidian species, binds to DNA and disrupts cancer cell replication. (7) (8) Other notable substances include plitidepsin, which blocks the activity of key protein factors needed for tumor cell survival, and eudistomin H, a brominated indole alkaloid that triggers programmed cell death in cancer lines. (9) (10) Beyond these, ascidians also make didemnins, bistramides, and lamellarins each showing promise in laboratory studies for their ability to induce cancer cell apoptosis and halt tumor growth. (8) (11) These compounds often act by generating reactive oxygen species within tumor cells or by disrupting mitochondrial function, leading to cell death without harming healthy tissues. Because they come from a natural source, these chemicals may cause fewer side effects than traditional chemotherapy. Ongoing research aims to refine these marine-derived nutrients into effective treatments, offering hope for new, gentler cancer therapies.
3. Reduces inflammation
Ascidians harbor a suite of natural compounds that help calm inflammatory responses. In particular, sulfated polysaccharides extracted from sea squirts exhibit broad anti-inflammatory actions akin to those of heparin but without unwanted blood-thinning effects. (12) Additionally, the tunic of edible ascidians provides omega-3 fatty acids notably eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which support immune balance by modulating key inflammatory mediators. (13) (14) Beyond lipids, colonial ascidians produce antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase that neutralize reactive oxygen species and reduce tissue swelling. (15) Marine tunicates also yield bioactive amino acid derivatives, including herdmanines, that interfere with the production of pro-inflammatory cytokines like TNF-α and IL-1β, thereby dampening cellular signaling cascades. (16) Collectively, these nutrients act through multiple mechanisms binding selectins to prevent leukocyte adhesion, inhibiting NF-κB and MAPK signaling pathways, and suppressing enzymes such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) to maintain healthy inflammatory control and promote overall well-being.
4. Strengthens the immune system
Remarkably, ascidians such as sea squirts harbor novel polysaccharides that support the body’s natural defenses by modulating inflammatory processes and promoting immune balance. (12) Interestingly, research has identified oversulfated dermatan sulfate compounds that exhibit significant anti-inflammatory activity without unwanted anticoagulant effects, providing templates for immune-supportive agents. (12) Equally important, the tunic lipids of sea squirts are rich in omega-3 fatty acids notably eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which enhance macrophage function and regulate the release of immune signaling molecules such as nitric oxide and prostaglandin E2. (17) (18) Moreover, specific fucosylated chondroitin sulfates from ascidians have been shown to block selectin-mediated cell adhesion, reducing unwarranted leukocyte infiltration and supporting tissue health. (12) (19) Even under repeated exposure to microbial challenges, sea squirts demonstrate an ability to “train” their innate immune system, resulting in heightened phagocytic responsiveness and refined gene expression in immune pathways. (20) Finally, carotenoids present in the body wall of certain ascidians contribute antioxidant protection, preserving cellular integrity during immune activation. (17) (21) Collectively, these bioactive compounds illustrate how ascidians fortify the immune system through a diverse arsenal of nutrients and polysaccharides.
5. Supports heart health
Remarkably, ascidians commonly known as sea squirts produce unique bioactive compounds that may support cardiovascular wellness. Studies reveal that these marine organisms possess fluorescein-labeled dextran, a high–molecular-weight polysaccharide, which highlights robust, closed circulatory systems similar to those found in vertebrates. (22) This suggests sea squirts naturally synthesize polysaccharide structures that help maintain vessel integrity and fluid balance. In addition, research on the colonial sea squirt Botryllus schlosseri identifies the presence of HCN (hyperpolarization-activated cyclic nucleotide–gated) channels in their cardiac tissues, analogous to human pacemaker cells. (23) HCN channels regulate rhythmic contractions, offering insights into how certain alkaloid-like molecules in sea squirts may influence heart rate stability. Furthermore, comparative genomics has uncovered that ascidians have mitochondrial peptides with antioxidant properties that protect cardiac cells from oxidative stress, a key factor in heart disease prevention. (24) Collectively, the presence of polysaccharides like fluorescein dextran, HCN-modulating compounds, and mitochondrial antioxidants in sea squirts underscores their potential as a natural source of nutrients and bioactives for supporting heart health. (22)(24)(23)
6. Helps regulate blood sugar
Interestingly, sea squirts, also known as ascidians, are rich in bioactive compounds that help maintain healthy blood sugar levels. They contain high amounts of the antioxidant pigment astaxanthin, which supports proper glucose metabolism by enhancing cellular responses to insulin. (25) Moreover, ascidians accumulate hesperetin, a flavonoid known for its blood sugar–regulating properties, helping balance carbohydrate processing in the body. (25) (26) In addition to these pigments, ascidian tissues are abundant in unsaturated fatty acids and a variety of amino acids, which provide essential nutrients that aid in stabilizing blood glucose. (25) (26) These organisms also harbor small molecules structurally related to common diabetes medications, such as metformin‐like and nateglinide‐like compounds, suggesting potential for natural support in glucose regulation. (25) (27) Furthermore, ascidians produce vanadium‐binding proteins, which contribute to better sugar utilization and help protect against blood sugar spikes. Overall, including ascidian‐derived nutrients in the diet may offer a complementary approach to supporting healthy blood sugar control, thanks to their unique combination of antioxidants, flavonoids, fatty acids, and bioactive peptides. (25)
7. Improves skin health and reduces signs of aging
Ascidians, commonly known as sea squirts, offer a wealth of bioactive compounds that support skin health by protecting and rejuvenating the extracellular matrix. Early research highlights that extracts from the tunic of Styela clava contain collagenase, elastase, and hyaluronidase inhibitors, which help maintain skin elasticity and firmness by preventing the breakdown of collagen and elastin fibers. (28) (29) Moreover, these extracts are rich in antioxidants capable of scavenging free radicals, thereby reducing oxidative stress that contributes to wrinkle formation and skin aging. (28) (29) In addition to enzymatic inhibitors, specific fatty acid amides such as erucamide and stearamide have been identified in sea squirt extracts; these molecules further enhance the skin’s structural integrity and resilience. (30) Complementary studies suggest that ascidians also provide plasmalogens, lipid molecules that support cell membrane health and may reduce age-related decline in skin function and appearance. (30) Together, these diverse nutrients from enzyme-inhibiting peptides to protective lipids work synergistically to minimize signs of aging, improve hydration, and preserve skin’s youthful texture, making ascidians a promising natural ingredient for anti-aging skincare.
Applications in Modern Medicine and Biotechnology
Ascidians, or sea squirts, are prolific sources of bioactive compounds and biomaterials with diverse therapeutic and industrial applications:
- Cancer Therapy: Bioactive metabolites such as trabectedin, derived from Ecteinascidia turbinata, are approved chemotherapeutic agents for soft tissue sarcoma and ovarian cancer.
- Immunomodulation and Antiviral: Extracts from Halocynthia roretzi exhibit anti-inflammatory and antiviral properties, enhancing immune responses against pathogens including SARS-CoV-2 in vitro.
- Melanoma Treatment: Palmerolide A, produced by microbiome symbionts of Antarctic ascidians, induces apoptosis in melanoma cells and is a promising lead for skin cancer therapeutics.
Beyond pharmaceuticals, ascidians contribute to biotechnology through their unique ability to biosynthesize cellulose (tunicin) for sustainable biomaterials and harbor vanadium-accumulating bacteria useful in bioremediation. Their simple embryonic models also enable high-throughput toxicity and neurodevelopmental screening, positioning ascidians at the forefront of marine blue biotechnology.
Safety Considerations and Potential Concerns of Ascidians Sea Squirts
Introducing the topic of safety considerations and potential concerns related to ascidians, or sea squirts, requires understanding both their ecological roles and their biochemical compositions. Ascidians are known to accumulate a range of bioactive compounds, including essential omega-3 fatty acids such as EPA and DHA, which support cardiovascular and cognitive health. They also produce unique secondary metabolites like ecteinascidin-743 and didemnilactones, noted for their anticancer properties. However, these same filtering behaviors that concentrate beneficial nutrients can also lead to the accumulation of environmental pollutants, such as heavy metals and persistent organic chemicals, raising concerns about seafood safety and ecosystem health. Furthermore, their rapid growth and colonization may introduce imbalances in local marine communities, potentially affecting biodiversity and aquaculture operations. Recognizing these dual aspects of ascidians as both valuable bioresources and potential vectors for contaminants is essential for developing guidelines that protect both human consumers and marine ecosystems.
Conclusion
In conclusion, ascidians, or sea squirts, stand out as remarkable marine organisms that combine unique nutritional value with a diverse array of bioactive compounds offering potential benefits for brain health, cancer prevention, inflammation control, immune support, cardiovascular function, blood sugar regulation, and skin vitality. Their role in modern medicine and biotechnology underscores their promise as natural sources for therapeutic agents and sustainable biomaterials. However, while their health-promoting properties are supported by growing scientific evidence, safety concerns such as heavy metal accumulation and ecological impacts highlight the need for careful research and responsible use. Overall, ascidians represent a fascinating intersection of nutrition, medicine, and environmental science, offering significant opportunities for future wellness and innovation.