(P03-034-23) Dietary Sugar Kelp (Saccharina latissima) Inhibits Adipose Tissue Inflammation and Fibrosis in Diet-Induced Obesity Mice

Objectives: We showed that U.S.-grown sugar kelp, a brown seaweed, inhibits inflammation and fibrosis in the liver and white adipose tissue (WAT) in male diet-induced obesity (DIO) mice. In this study, we explored whether the consumption of sugar kelp can have similar benefits in female DIO mice.

Methods: Seven-week-old male and female mice were assigned to a low-fat control (n=8), a high-fat/high-sucrose/high-cholesterol control (HF, n=8-10), or an HF containing sugar kelp (HF-Kelp; 6.0% dried sugar kelp powder by wt, n=8-10). Mice were subjected to oral glucose tolerance tests and indirect calorimetry at 12 weeks on the experimental diets. Serum, tissue, and cecum samples were collected after 16 weeks.

Results: Sugar kelp consumption lowered body weight gain, total body fat, gonadal WAT (gWAT) weight, serum triglycerides, total cholesterol and glucose, and glucose intolerance compared with HF in male but not female mice. Also, in the gWAT of the HF-Kelp group, proinflammatory gene expression, crown-like structure number, fibrogenic genes, and fibrosis were lower than HF control only in males. Metabolic rates, energy expenditure, and physical activity were higher with sugar kelp consumption in males. However, gut microbiome analysis showed sugar kelp elevated observed species and altered beta diversity in both males and females.

Conclusions: Sugar kelp exerts sex-dependent effects on obesity-induced inflammation and fibrosis in WAT, attributed to increased metabolic rates, energy expenditure, and physical activity. Presumably, we did not observe the protective effects of sugar kelp in female mice as they are resistant to obesity-associated dysfunctions compared with males. Therefore, further studies are warranted to assess the sex-dependent effects of sugar kelp consumption on obesity and WAT inflammation and fibrosis.

Funding Sources: USDA Hatch and USDA NIFA