Tropical seaweeds improve cardiovascular and metabolic health of diet-induced obese and hypertensive rats

Seaweeds have been an important part of the diet of coastal populations in Asia possibly for millennia but only a few scattered coastal communities in Europe and the Americas have maintained these traditions. Our studies have investigated the potential of two tropical seaweeds grown commercially in Asia, Sarconema and Caulerpa spp., as functional foods for the reversal of metabolic syndrome and possible mechanisms. Sarconema spp. are a source of carrageenans used as thickening and gelling agents in foods, while Caulerpa spp. are consumed in Southeast Asia as low-energy foods with high contents of vitamins and minerals. For our studies, male Wistar rats were divided into groups in a 16-week protocol: corn starch diet-fed rats (C); C rats supplemented with 5% dried seaweed for the last 8 weeks; high-carbohydrate, high-fat diet-fed rats (H); and H rats supplemented with 5% dried seaweed for the last 8 weeks. H rats developed obesity, hypertension, dyslipidaemia, glucose intolerance, fatty liver and increased left ventricular collagen deposition, infiltration of inflammatory cells and plasma liver enzyme activities. Seaweed supplementation decreased body weight, abdominal and liver fat, systolic blood pressure, plasma lipid concentrations, plasma activities of liver enzymes and collagen deposition. Furthermore, seaweed supplementation modulated gut microbiota. Possible mechanisms for improved cardiovascular and metabolic health include a reduced infiltration of inflammatory cells into organs as well as an increased intake of fibre modulating gut microbiota composition. (This article belongs to the Proceedings of First International Electronic Conference on Nutrients, Microbiota and Chronic Disease

Nannochloropsis oceanica as a microalgal food intervention in diet-induced metabolic syndrome in rats

The microalgal genus Nannochloropsis has broad applicability to produce biofuels, animal feed supplements and other value-added products including proteins, carotenoids and lipids. This study investigated a potential role of N. oceanica in the reversal of metabolic syndrome. Male Wistar rats (n = 48) were divided into four groups in a 16-week protocol. Two groups were fed either corn starch or high-carbohydrate, high-fat diets (C and H, respectively) for the full 16 weeks. The other two groups received C and H diets for eight weeks and then received 5% freeze-dried N. oceanica in these diets for the final eight weeks (CN and HN, respectively) of the protocol. The H diet was high in fructose and sucrose, together with increased saturated and trans fats. H rats developed obesity, hypertension, dyslipidaemia, fatty liver disease and left ventricular fibrosis. N. oceanica increased lean mass in CN and HN rats, possibly due to the increased protein intake, and decreased fat mass in HN rats. Intervention with N. oceanica did not change cardiovascular, liver and metabolic parameters or gut structure. The relative abundance of Oxyphotobacteria in the gut microbiota was increased. N. oceanica may be an effective functional food against metabolic syndrome as a sustainable protein source

Brown seaweed Sargassum siliquosum as an intervention for diet-induced obesity in male wistar rats

The therapeutic potential of Sargassum siliquosum grown in Australian tropical waters was tested in a rat model of metabolic syndrome. Forty-eight male Wistar rats were divided into four groups of 12 rats and each group was fed a different diet for 16 weeks: corn starch diet (C); high-carbohydrate, high-fat diet (H) containing fructose, sucrose, saturated and trans fats; and C or H diets with 5% S. siliquosum mixed into the food from weeks 9 to 16 (CS and HS). Obesity, hypertension, dyslipidaemia, impaired glucose tolerance, fatty liver and left ventricular fibrosis developed in H rats. In HS rats, S. siliquosum decreased body weight (H, 547 ± 14; HS, 490 ± 16 g), fat mass (H, 248 ± 27; HS, 193 ± 19 g), abdominal fat deposition and liver fat vacuole size but did not reverse cardiovascular and liver effects. H rats showed marked changes in gut microbiota compared to C rats, while S. siliquosum supplementation increased gut microbiota belonging to the family Muribaculaceae. This selective increase in gut microbiota likely complements the prebiotic actions of the alginates. Thus, S. siliquosum may be a useful dietary additive to decrease abdominal and liver fat depositio