Effects of porphyran (POR), a sulfated galactan from an edible red alga Porphyra yezoensis (Susabinori), on growth and lipid metabolism were examined using Sprague-Dawley rats fed a cholesterol-free diet. Rats were divided into four dietary groups: those fed diets containing 5% cellulose (control), agar or two types of POR differing in sugar composition and sulfate content (low sulfate content, LS-POR and high sulfate content, HS-POR) for 3 weeks. Ingestion of the diets containing LS- and HS-POR resulted in a significant decrease in food intake and body weight gain relative to the control diet. Renal adipose tissue weight and serum cholesterol level were also significantly lower in the LS-POR group and the HS-POR group than in the other groups. In contrast, agar, which consists of the same sugar components as POR, had no effect on the above-mentioned growth and lipid parameters. Fecal excretion of neutral sterols was markedly enhanced by POR ingestion, suggesting that POR has a potent effect to interfere with the absorption of neutral sterols within the gastrointestinal tract. Fecal excretion of fatty acids and neutral sterols was significantly higher in the LS-POR group than in the HS-POR group, and it was suggested that the ability to interfere with the absorption of cholesterol and fatty acid within the gastrointesitinal tract depends on the sulfation rate of porphyan.
All Science Journal Classification (ASJC) codes
- Food Science
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering