For this blog, I’d like to specifically point you toward a key section of Kenneth G. Collins et al.’s publication, “Looking Beyond the Terrestrial: The Potential of Seaweed Derived Bioactives to Treat Non-Communicable Diseases”. The details include research and findings related to diabetes and obesity and will serve as the secondary theme of this blog series.
In conditions like diabetes, where the body’s ability to neutralize reactive oxygen species (ROS) is surpassed by their production, oxidative stress develops. Oxidative stress has been reported to be the underlying cause of insulin resistance, beta cell dysfunction, glucose intolerance, and the development of type 2 diabetes. Although synthetic antioxidants are commercially available, their use is currently limited due to side effects such as promoting cancer cells. For this reason, there is growing interest in using naturally derived antioxidants for diabetes treatment. Seaweeds, being abundant in various antioxidant compounds, are generally viewed as a significant source of these beneficial substances. Marine-derived polyphenolic compounds can act as scavengers of ROS and modulate glucose-induced oxidative stress. It has been suggested that polyphenols have anti-diabetic properties.
The brown alga Tubinaria ornata (Phaeophyceae) has shown superoxide scavenging activity that may be effective in reducing O2 levels that rise during oxidative stress in the body. A methanol extract of E. cava containing high levels of polyphenols and strong ROS scavenging ability significantly reduced blood glucose levels and increased insulin concentrations when given to Type 1 diabetic rats.
Control of postprandial hyperglycemia is crucial in the treatment of diabetes and the prevention of cardiovascular complications. One of the treatment methods is to prevent glucose absorption by inhibiting carbohydrate hydrolases such as α-amylase and α-glucosidase. In an effort to quickly lower blood glucose levels, which increase after meals, synthetic α-amylase and α-glucosidase inhibitors have been developed. However, these medications can cause various side effects, including flatulence, abdominal cramps, vomiting, and diarrhea. Seaweeds are known for their ability to inhibit starch digestive enzymes and are an untapped source of enzyme inhibitors for the treatment of diabetes. In a study investigating the α-amylase and α-glucosidase inhibitory effects of 15 species of Irish seaweeds, extracts of F. vesiculosus showed strong α-glucosidase inhibitory effects. In a study carried out with samples of A. nodosum, P. palmata, and Alaria esculenta (brown algae), A. nodosum extract was found to be the most active of the three seaweeds. The same extract was also able to inhibit the activity of α-glucosidase at low levels. In induced diabetic mice, extracts of Petalonia bingamiae (brown algae) (PBE) have been demonstrated to have antidiabetic properties. Treatment with the extract led to a decrease in blood glucose levels in diabetic mice, with improved tolerance to glucose.
Numerous studies have shown that a diet that includes whole, unprocessed plant foods rich in phytochemicals may be beneficial for metabolic disorders such as diabetes. Obese mice fed an ethanol extract of U. pinnatifida showed that it could prevent insulin resistance and hepatic fat accumulation by regulating hepatic glucose and lipid homeostasis in high-fat-induced obese mice compared with a high-fat-fed control group. Six weeks of I. okamurae extract feeding in mice reduced blood glucose by modifying hepatic glucose metabolism enzymes and improving insulin sensitivity.
Dietary fiber found in seaweeds such as alginates may reduce obesity-related glycemic disorders when incorporated into the diet. A study of 40 healthy men found that it was able to attenuate the glycemic response after lunch consumption.
One of the serious consequences of diabetes is the development of hyperglycemia-induced diabetic retinopathy (DR), which is a common cause of blindness in many countries. Brown algae-derived LMWFs are known to exhibit multiple biological activities (anti-inflammatory, antioxidant, anti-aggregatory) that may be effective in treating ischemic diseases such as diabetic retinopathy. Mice with streptozotocin-induced diabetes were fed diets containing LMWFs or calcium besylate for 4 months to examine the protective role of LMWFs on the development of diabetic retinopathy, hyperglycemia-promoted vascular endothelial growth factor (VEGF) production, and cell proliferation of microvascular endothelial cells. LMWFs attenuated diabetes-induced pathological changes in the retina in vitro and inhibited neovascularization.
Obesity is considered a gateway condition for several chronic diseases and is a major factor in the development of hypertension, type 2 diabetes, cardiovascular disease, and some types of cancer. Childhood obesity has been described as the most important health challenge of the 21st century, with concerns that individuals who were obese at a young age are more likely to remain obese into adulthood, and therefore more likely to develop cardiovascular disease, cancer, and diabetes. One method of treatment is to manipulate appetite and reduce the amount and calories of food ingested. Dietary alginate slows the rate at which nutrients are absorbed into the intestine and promotes satiety, both of which are important in controlling obesity and type 2 diabetes. Once ingested, the alginate creates a gel in the stomach through ionic gelation triggered by gastric acid. This gel reduces the rate of gastric emptying, stimulates gastric stretch receptors, reduces nutrient intake, and affects the postprandial glycemic response.
Intake of oily foods and seaweed is one of the factors that increase the risk of developing metabolic syndrome, and data from animal studies suggest that seaweed consumption may prevent weight gain. Fucoidan from sporophyll of U. pinnatifida was investigated for its anti-obesity potential through the inhibition of inflammation-related cytokines. In 3T3-L1 adipocytes undergoing adipogenesis, the notable presence of fucoidan led to a significant suppression of growth factor-activated receptor gamma, C/EBPα, and adipocyte protein 2, accompanied by a decrease in the expression of genes associated with inflammation. Fucoidan also reduced the synthesis of ROS and lipid accumulation in the cells.
Source: Source: Mar Drugs. 2016 Mar; 14(3): 60. doi: 10.3390/md14030060