9. Alginates in Metabolic Syndrome

Alginates extracted from seaweeds are widely used for nutrition, but they are underutilised for the prevention or reversal of human disease. Alginates are long chains of α-L-guluronic acid and β-D-mannuronic acid from brown seaweeds that act as readily available, low cost, non-toxic and biodegradable biopolymers. Sodium alginates are primarily used for the management of gastrointestinal tract disorders, but they are of potential use to attenuate the components of the metabolic syndrome including obesity, type 2 diabetes, hypertension, non-alcoholic fatty liver disease and dyslipidaemia. As prebiotics, alginates changed the gut microbiome to increase production of short-chain fatty acids as substrates for Bifidobacteria. Alginates inhibited pancreatic lipases and so decreased triacylglycerol breakdown and uptake. Treatment with alginates decreased food intake by inducing satiety and increased weight loss in patients on a calorie-restricted diet. Both glucose and fatty acid uptake were reduced. In rat models of hypertension, alginates decreased blood pressure. An alginate-antacid combination is an effective treatment of gastric reflux disease by forming a raft on the gastric contents. Alginates are important as drug carriers in microparticles and nanoparticles to increase drug bioavailability, for example, in drugs used for treatment of metabolic syndrome. Alginates are also used to protect cells during transplantation from immune responses of the host, allowing potential long-term control of some endocrine disorders such as type 1 diabetes and increased thermogenesis by brown adipocytes in obesity. There are many potential uses for these versatile biopolymers in the treatment of human disease.