Effects of <scp><i>Palmaria palmata</i></scp> on lipid metabolism and glycemic control in participants with hypercholesterolemia in a randomized double‐blind placebo‐controlled trial

Abstract

BACKGROUND: Red algae have been reported to improve lipid and glucose metabolism in rats. We investigated the effects of Palmaria palmata (P. palmata), a red alga from northern Japan, on lipid metabolism and glycemic control in participants with hypercholesterolemia. METHODS: We conducted an 8-week, randomized, double-blind, placebo-controlled, and parallel-group comparison trial. The study enrolled Japanese participants with a serum low-density protein cholesterol (LDL-C) ≥120 mg/dL. The participants were randomly assigned to take either capsules containing P. palmata (2 g/day) or placebo capsules. The primary endpoint was the change in LDL-C from baseline to week 8 and the secondary endpoints were the changes in other lipid parameters and glycemic control. RESULTS: Of the 104 participants completed the study protocol. There were no significant differences in change in LDL-C, body mass index, waist circumference, or glycemic control between the two groups. However, serum triglyceride showed significantly greater improvement in women in the P. palmata group (-9.0 [-25.0, +5.0]) vs. those in the placebo group (-1.0 [-11.0, +19.0]; p = .03). CONCLUSIONS: The present study did not show that P. palmata had significant effect on serum LDL-C nor glycemic control, but hypertriglyceridemia could be ameliorated by administration of P. palmata in women.