Twelve weeks’ treatment with a polyphenol-rich seaweed extract increased HDL cholesterol with no change in other biomarkers of chronic disease risk in overweight adults: A placebo-controlled randomized trial

Cardiovascular diseases (CVD) are the leading global cause of death. Strategies to reduce CVD risk are urgently needed. Polyphenols represent a class of bioactive compounds with potential to moderate biochemical risk factors for CVD (cholesterol, triglycerides, glucose, and inflammation). This double-blind, placebo-controlled, randomized parallel-groups trial investigated the effect of a polyphenol-rich seaweed (Fucus vesiculosus) extract on biochemical markers of CVD risk. Thirty-four overweight and obese adults (21 female, 13 male) with elevated low-density lipoprotein cholesterol (>2.0 mmol/L) were randomized to either the seaweed extract (2000 mg/d) or placebo for twelve weeks. Fasting blood samples were collected at baseline, week six and week twelve to assess biochemical markers. Tests of cognitive performance and mood were performed at baseline, week six and week twelve. A 9.5% (-2.3, 12.9) increase in high-density lipoprotein (HDL) cholesterol was identified following the seaweed extract (baseline: mean (SD) 1.28 (0.23) mmol/L, week 12: 1.35 (0.24) mmol/L) which was different to placebo (baseline: 1.38 (0.54) mmol/L, week 12: 1.35 (0.59) mmol/L) (P=.045). No changes were identified in low-density lipoprotein cholesterol, total cholesterol, triglycerides, glucose, insulin, interleukin (IL)-2, IL-6, IL-8, IL-10, or tumour necrosis factor-alpha levels in the blood, or in cognitive performance or mood between the treatment and placebo groups. Despite the small increase observed in HDL cholesterol, the polyphenol-rich seaweed extract did not change CVD risk factors in adults with high fasting lipids. A larger sample size would be required to confirm the clinical relevance of the changes in HDL cholesterol.