Context: Seaweed is a promising source of anti-obesity agents, including polysaccharides, proteins, polyphenols, carotenoids, and n-3 long-chain polyunsaturated fatty acids. The anti-obesity effects of such compounds may be due to several mechanisms, including inhibition of lipid absorption and metabolism, effect on satiety, and inhibition of adipocyte differentiation.
Objective: The aim of this study was to assess the evidence from human randomized controlled trials for the effects of seaweed on body-weight status as well as lipid and nonlipid parameters in adults with overweight and obesity.
Data sources: Four databases-Medline, Scopus, Web of Science, and Cochrane Library-were searched from December 2022 to June 2023 using the following key words: Seaweed OR fucoxanthin OR alginates OR fucoidans OR phlorotannin's OR macroalgae OR marine algae AND obesity OR overweight OR BMI OR body mass index.
Data extraction: Eleven interventional studies (10 parallel and 1 crossover) were extracted.
Data analysis: Meta-analysis showed a significant effect, favoring the intervention group for BMI (body mass index) (standardized mean difference [SMD]: -0.40; 95% CI: -0.65 to -0.16 kg/m2; P = 0.0013) and percentage of fat mass (SMD: -1.48; 95% CI: -2.66% to -0.30%, P = 0.0138). The results were seen when refined or extracted brown seaweed (BMI) or only refined brown seaweed (% fat mass) were administered to participants for at least 8 weeks. Moreover, a significant overall effect of seaweed supplementation on total cholesterol (SMD: -7.72; 95% CI: -12.49 to -2.95 mg/dL; P = 0.0015) and low-density-lipoprotein cholesterol (SMD: -7.33; 95% CI: -11.64 to -3.02 mg/dL; P < 0.001) was noted. Any significant effects of seaweed on glucose metabolism were not shown.
Conclusion: Edible seaweed supplementation shows potential for managing obesity and disorders of the blood lipid profile when administered to participants for at least 8 weeks.
Systematic review registration: PROSPERO registration no. CRD42022378484 (www.crd.york.ac.uk/PROSPERO).
Keywords: alginate; brown seaweeds; fucoidan; fucoxanthin; obesity; overweight.
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