Ascophyllum nodosum, a brown seaweed, has been investigated in recent years for its potential benefits in metabolic syndrome, primarily due to its bioactive components such as polyphenols, fucoidans, and alginates. These compounds are thought to influence carbohydrate and lipid metabolism. Several small human clinical trials and animal studies indicate that Ascophyllum nodosum extracts may reduce postprandial blood glucose spikes, improve insulin sensitivity, and modestly lower LDL cholesterol. The mechanism is believed to be related to inhibition of digestive enzymes like alpha-amylase and alpha-glucosidase, slowing carbohydrate absorption, and modulating gut microbiota.

For example, a randomized controlled trial published in Food & Function (2018) found that supplementation with Ascophyllum nodosum and Fucus vesiculosus extracts significantly reduced postprandial glycemic response in overweight adults. Animal studies support these findings, showing improved insulin resistance and lipid profiles. However, the clinical evidence remains limited due to small sample sizes, short study durations, and a lack of replication.

There is little historical or traditional use of Ascophyllum nodosum for metabolic disorders in folk medicine; its application is primarily based on recent scientific inquiry rather than longstanding practice. Thus, while the use is scientifically motivated, the strength of evidence is moderate to weak, warranting further research.