Alginate, an algal polysaccharide, is widely used in the food industry as a stabilizer, or as a thickening or emulsifying agent. As an indigestible polysaccharide, alginate may also be viewed as a source of dietary fiber. Previous work has suggested that dietary fibres may protect against the onset and continuation of a number of cardiovascular and gastrointestinal diseases. This article aims to examine what is currently understood about the fiber-like activities of alginate, particularly its effects on intestinal absorption and the colon, and therefore aims to gauge the potential use of alginate as a dietary supplement for the maintenance of normal health, or the alleviation of certain cardiovascular or gastrointestinal diseases.

Recommendations for whole-grain (WG) intake are based on observational studies showing that higher WG consumption is associated with reduced CVD risk. No large-scale, randomised, controlled dietary intervention studies have investigated the effects on CVD risk markers of substituting WG in place of refined grains in the diets of non-WG consumers. A total of 316 participants (aged 18–65 years; BMI>25 kg/m²) consuming < 30 g WG/d were randomly assigned to three groups: control (no dietary change), intervention 1 (60 g WG/d for 16 weeks) and intervention 2 (60 g WG/d for 8 weeks followed by 120 g WG/d for 8 weeks). Markers of CVD risk, measured at 0 (baseline), 8 and 16 weeks, were: BMI, percentage body fat, waist circumference; fasting plasma lipid profile, glucose and insulin; and indicators of inflammatory, coagulation, and endothelial function. Differences between study groups were compared using a random intercepts model with time and WG intake as factors. Although reported WG intake was significantly increased among intervention groups, and demonstrated good participant compliance, there were no significant differences in any markers of CVD risk between groups. A period of 4 months may be insufficient to change the lifelong disease trajectory associated with CVD. The lack of impact of increasing WG consumption on CVD risk markers implies that public health messages may need to be clarified to consider the source of WG and/or other diet and lifestyle factors linked to the benefits of whole-grain consumption seen in observational studies.

Cereal-based foods are key components of the diet and they dominate most food-based dietary recommendations in order to achieve targets for intake of carbohydrate, protein and dietary fibre. Processing (milling) of grains to produce refined grain products removes key nutrients and phytochemicals from the flour and although in some countries nutrients may be replaced with mandatory fortification, overall this refinement reduces their potential nutritional quality. There is increasing evidence from both observational and intervention studies that increased intake of less-refined, whole-grain (WG) foods has positive health benefits. The highest WG consumers are consistently shown to have lower risk of developing CVD, type 2 diabetes and some cancers. WG consumers may also have better digestive health and are likely to have lower BMI and gain less weight over time. The bulk of the evidence for the benefits of WG comes from observational studies, but evidence of benefit in intervention studies and potential mechanisms of action is increasing. Overall this evidence supports the promotion of WG foods over refined grain foods in the diet, but this would require adoption of standard definitions of ‘whole grain’ and ‘whole-grain foods’ which will enable innovation by food manufacturers, provide clarity for the consumer and encourage the implementation of food-based dietary recommendations and public health strategies.

Alginates are comprised of mannuronic (M) and guluronic acid (G) and have been shown to inhibit enzyme activity. Pancreatic lipase is important in dietary triacylglycerol breakdown; reducing pancreatic lipase activity would reduce triacylglycerol breakdown resulting in lower amounts being absorbed by the body. Lipase activity in the presence of biopolymers was assessed by enzymatic assay using natural and synthetic substrates. Alginate inhibited pancreatic lipase by a maximum of 72.2% (±4.1) with synthetic substrate (DGGR) and 58.0% (±9.7) with natural substrate. High-G alginates from Laminaria hyperborea seaweed inhibited pancreatic lipase to a significantly higher degree than High-M alginates from Lessonia nigrescens, showing that inhibition was related to alginate structure. High-G alginates are effective inhibitors of pancreatic lipase and are used in the food industry at low levels. They could be included at higher levels in foods without altering organoleptic qualities, potentially reduce the uptake of dietary triacylglycerol aiding in weight management.