Fucoidan: a review of human trials does not confirm anti-inflammatory promises

Five studies, with no quantified overall result

The authors searched PubMed, Scopus and Web of Science for human intervention studies, following PRISMA guidelines. The inclusion criteria covered healthy adults, people with metabolic or inflammatory disorders and patients with cancer.

Five studies were included: three randomized controlled trials and two open-label studies conducted in patients with cancer. The interventions lasted 2 to 24 weeks. The abstract does not specify the sample sizes or comparators for each trial.

Differences in methods and measured outcomes prevented a meta-analysis. The review therefore provides no pooled numerical estimate of fucoidan’s effect.

Biological signals, not an established clinical benefit

Some controlled trials reported reductions in selected pro-inflammatory cytokines, sex-related differences in changes in natural killer (NK) cell activity and changes in the gut microbiota of people at metabolic risk. However, these observations were not consistently replicated across studies.

A change in an inflammatory marker or immune cell activity does not, on its own, demonstrate improved health. The abstract does not allow any concrete benefit for symptoms or quality of life to be quantified.

In the cancer studies, the authors report short-term decreases in inflammatory markers and stable quality-of-life measures. Tumor-related findings remain inconclusive: this review does not support presenting fucoidan as an anticancer treatment.

Tolerability observed over a limited period

No serious adverse events were reported in the included studies, and fucoidan was generally well tolerated. This finding applies to the participants, preparations and durations studied. It does not guarantee long-term safety or the safety of all commercially available products.

Differences between the populations and the characteristics of the fucoidan studied also limit how broadly the findings can be generalized. The authors call for adequately powered randomized trials using well-characterized preparations and clinically relevant outcomes.

What we can take away

Fucoidan shows exploratory signals in humans, but this review is not enough to justify buying it for a demonstrated anti-inflammatory or immune benefit.