Effect of Wakame Containing Diets on Hepatic Gene Expressions in Rat

Wakame is an edible seaweed that is a common constituent in the Japanese diet. Previous studies showed that wakame consumption is associated with prevention of metabolic syndrome; however, the molecular mechanisms of this protective effect are poorly understood. To determine if the expression of hepatic genes is affected by the ingestion of brown seaweed, Undaria pinnatifida (wakame), rats were fed diets containing 0, 0.1, or 1.0 g/100 g dried wakame powder for 28 days. Administration of 1% wakame significantly decreased total serum total cholesterol levels. Hepatic gene expression was investigated using DNA microarray analysis. Microarray analysis showed that wakame suppresses the lipogenic pathway by downregulating SREBF-1. Moreover, bile acid biosynthesis and gluconeogenesis are promoted by upregulation of the PPAR signaling pathway, which leads to a reduction in the accumulation of cholesterol and promotion of β-oxidation. These results provide useful genetic information about various biochemical processes by which wakame regulates energy metabolism.