Results from a double-blind, placebo-controlled trial show that a seaweed-derived prebiotic can deliver gut health benefits at a low dose without causing bloat or intestinal discomfort.¹ The prebiotic Ocean Actives H+ from Oceanium is from a brown seaweed Saccharina latissima extract, containing significant amounts of mixed fucoidan species, proteins, and polyphenols. Ocean Actives H+ was tested for its ability to modulate the gut biome and support immune health, with its health benefits initially announced earlier this year.

Study design: assessing gut health benefits

The study, “Gut Microbiome Modulation and Health Benefits of a Novel Fucoidan Extract from Saccharina latissima: A Double-Blind, Placebo-Controlled Trial,” was published in Microorganisms in June 2025. For four weeks, ninety-one healthy participants ages were given capsules of a low dose of the extract (SLE-F), a high dose, or placebo twice daily. The low dose was 125 mg and the high dose was 500 mg. Microbiome composition was assessed, as well as pathway analysis, taxonomic shifts, and microbial functions.

Study results: Ocean Actives H+ extract and the gut microbiome

By the end of four weeks, results indicated a dose-dependent response was demonstrated.

• The high dose of the extract resulted in increases in beneficial bacteria including Bifidobacterium, Faecalibacterium, and Lachnospiraceae, as well as decreases of bacteria associated with inflammation, including Enterobacteriaceae and Pseudomonadota
• The low dose showed limited functional changes, primarily increasing Bifidobacterium, though only moderately
• An increase of short-chain fatty acid (SCFA) biosynthesis and carbohydrate metabolism was seen using a functional pathway analysis and using in vitro colonic simulations

As the study explains, SFCAs play a significant role in gut barrier integrity, immune support, and anti-inflammatory effects.

Small sample size, a short study duration, and lack of control over participants’ dietary variations were noted as limitations to the study. Overall, the extract was well tolerated and only mild side effects reported. “These findings support the potential of SLE-F as a safe and effective microbiome-modulating agent, warranting further study of the long-term use and synergy with dietary interventions,” the researchers concluded.

Applications of brown seaweed extract in supplements and functional foods

As a September 24 press release² from Oceanium explains, traditional prebiotics require a higher daily dose to be effective, about 5–10 g, and can result in gas and bloating, causing consumers to reduce their use.

“Consumers kept telling us that although their prebiotics work, they couldn’t handle the side effects,” stated Neil Waslidge, R&D Manager, Oceanium. “Our seaweed extract changes that as one tiny dose gives you powerful gut health benefits with 87% less gas production.”

The press release also noted that Ocean Actives H+ is water soluble and able to be added into functional foods and beverages, capsules, gummies, and other applications. It also received self-affirmed generally recognized as safe (GRAS) status in the U.S. Additionally, the company’s ingredients can be used for both humans and companion animals.

Oceanium explains that it uses green extraction technology and sustainably sourced seaweed, noting that seaweed stores carbon as it grows.

“Consumers increasingly want products that benefit both personal and planetary health,” stated Karen Scofield Seal, CEO and co-founder, Oceanium. “Our seaweed farming partners are essentially carbon-negative food producers, which aligns perfectly with sustainability-focused brands.”

As more studies validating systemic benefits continue, partnerships with supplement brands and functional food brands are anticipated to be announced soon.

References

1. Garcia, G.; Soto, J.; Valenzuela, C.; Bernal, M.; Barreto, J.; Luzardo, M.d.l.C.; Kazlauskaite, R.; Waslidge, N.; Bavington, C.; Cano, R.d.J. Gut Microbiome Modulation and Health Benefits of a Novel Fucoidan Extract from Saccharina latissima: A Double-Blind, Placebo-Controlled Trial. Microorganisms 2025, 13(7). DOI: 10.3390/microorganisms13071545
2. Oceanium. UK Company Solves Prebiotic Problem with Low-Dose Seaweed Extract Proven to Work Without the Bloat. September 24, 2025. (accessed 2025-09-26).