Objectives: To determine whether a fucoidan extract reduced insulin resistance and/or altered other cardiometabolic markers in an obese, nondiabetic population.
Design: Single-site, double-blinded, placebo-controlled, randomized controlled trial.
Setting/location: Hobart, Tasmania, Australia.
Subjects: Eligible subjects were obese, with no history of diabetes, and ages between 18 and 65 years.
Interventions: Subjects were randomly assigned, in even blocks of 10, to either active fucoidan 500 mg or placebo capsules twice daily for 90 days, with identical measurements performed at baseline and follow-up.
Outcome measures: The primary outcome was insulin resistance, defined by the homeostasis model of assessment (HOMA) values. Secondary outcomes were lipid profile, glycosylated hemoglobin, urea electrolytes and creatinine, liver function tests, full/complete blood count, fasting insulin, fasting glucose, quantitative insulin sensitivity check index, glucose area under the curve, weight, body mass index, waist circumference, and systolic and diastolic blood pressure. The trial was registered with the Australian New Zealand Clinical Trial Registry (ACTRN12614000495628) and the Therapeutic Goods Administration (2014/0348), and was funded by Marinova Pty. Ltd.
Results: There were no differences in the 90-day outcome measures between placebo and active treatment in the intention-to-treat-analysis (n = 35 for active, n = 37 for placebo). The mean change in HOMA scores was 0 for the placebo and -0.1 for the active groups (p = 0.73). Self-reported adherence was high, consistent with capsule counting at the conclusion of the trial.
Conclusions: Fucoidan taken twice daily for a period of 90 days did not markedly affect insulin resistance or other measured parameters of cardiometabolic health in an obese, nondiabetic cohort. This could be due to an intrinsic lack of efficacy, lower than measured adherence, or because longer therapy and/or higher baseline insulin resistance are required to exert a significant effect.
Keywords: fucoidan; glucose tolerance; obesity; prediabetes.