The Study
Dietary Dried Laver (Porphyra tenera) Modulates Gut Microbiota Composition and Diversity in Older Women with and Without Metabolic Syndrome: An Exploratory Pilot Study
This study watched what happened to the tiny bacteria in 24 women’s guts after they ate seaweed every day for 12 weeks. It saw some changes, but we don’t know if the seaweed caused them—maybe they just changed because of time, or because they ate other things differently. It’s like noticing your plant grew after you talked to it—you can’t say talking made it grow.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists gave older women a small amount of dried seaweed every day for 3 months to see if it changed their gut bacteria.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1More diverse gut bacteria is usually linked to better health, and these changes suggest seaweed might help rebalance gut microbes — especially in people with metabolic syndrome.
- 2After 12 weeks, their gut bacteria became more diverse.
- 3Women with metabolic syndrome saw bigger changes: good bacteria like Muribaculaceae and Paraprevotella increased, and a bad ratio (Firmicutes/Bacteroidetes) dropped more than in healthy women.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2026
Authors
Dayeon Shin, Suyeon Lee, Byunghun So, Chounghun Kang, Kyung Ju Lee
Related Content
Claims (6)
People who eat 30 or more different types of plants each week have higher gut microbiota diversity than those who eat fewer.
In older women, consuming 4 grams of dried laver daily for 12 weeks is linked to a lower Firmicutes/Bacteroidetes ratio in gut bacteria, with a stronger reduction in those who have metabolic syndrome.
In older women with metabolic syndrome, consuming 4 grams of dried laver daily for 12 weeks is associated with higher levels of the gut bacteria Muribaculaceae and Paraprevotella, which are known to produce short-chain fatty acids.
In older women aged 50 and above, eating 4 grams of dried laver every day for 12 weeks is linked to higher gut microbial diversity, measured by Chao1 and Fisher indices.
Daily consumption of 4 grams of dried laver for 12 weeks is associated with higher levels of the gut bacterium CAG_873 in older women without metabolic syndrome. This bacterium is involved in breaking down dietary fiber and producing short-chain fatty acids.
Daily consumption of 4 grams of dried laver for 12 weeks is linked to higher levels of the bacterium Tyzzerella in older women, including those with metabolic syndrome.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.