Prebiotics from Seaweeds: An Ocean of Opportunity?

Abstract

Seaweeds are an underexploited and potentially sustainable crop which offer a rich source of bioactive compounds, including novel complex polysaccharides, polyphenols, fatty acids, and carotenoids. The purported efficacies of these phytochemicals have led to potential functional food and nutraceutical applications which aim to protect against cardiometabolic and inflammatory risk factors associated with non-communicable diseases, such as obesity, type 2 diabetes, metabolic syndrome, cardiovascular disease, inflammatory bowel disease, and some cancers. Concurrent understanding that perturbations of gut microbial composition and metabolic function manifest throughout health and disease has led to dietary strategies, such as prebiotics, which exploit the diet-host-microbe paradigm to modulate the gut microbiota, such that host health is maintained or improved. The prebiotic definition was recently updated to “a substrate that is selectively utilised by host microorganisms conferring a health benefit”, which, given that previous discussion regarding seaweed prebiotics has focused upon saccharolytic fermentation, an opportunity is presented to explore how non-complex polysaccharide components from seaweeds may be metabolised by host microbial populations to benefit host health. Thus, this review provides an innovative approach to consider how the gut microbiota may utilise seaweed phytochemicals, such as polyphenols, polyunsaturated fatty acids, and carotenoids, and provides an updated discussion regarding the catabolism of seaweed-derived complex polysaccharides with potential prebiotic activity. Additional in vitro screening studies and in vivo animal studies are needed to identify potential prebiotics from seaweeds, alongside untargeted metabolomics to decipher microbial-derived metabolites from seaweeds. Furthermore, controlled human intervention studies with health-related end points to elucidate prebiotic efficacy are required.

Characterization and Application of an Alginate Lyase, Aly1281 from Marine Bacterium Pseudoalteromonas carrageenovora ASY5

“…Some studies have shown that AOS can lower blood sugar and blood lipid levels [8] and display anti-tumor [9] and anti-viral [10] abilities. Moreover, they can be used as prebiotic to promote the growth of probiotics, such as Bifidobacterium bifidum, Bifidobacterium longum [11], and Lactobacilli [12].…”

Seaweeds in Pig Nutrition

“…For details and information on the monosaccharide composition of the different polysaccharides mentioned, some excellent reviews are available [34,35].…”

Potential Use of Marine Seaweeds as Prebiotics: A Review

“…In vitro batch fermentation of laminarin for 24 h promoted an increase in Bifidobacterium and Bacteroides, and propionate and butyrate production [42]. Contradicting results by other researchers indicated that laminarin was not selectively fermented by Lactobacillus and Bifidobacterium, but could modify the composition, secretion and metabolism of the jejunal, ileal, caecal and colonic mucosa to protect against bacterial translocation [32]. In addition, laminarin increased the presence of Clostridium spp.…”

“…Green seaweeds contain mostly sulphated structural polysaccharides, like ulvans (the most abundant, representing 8-29% of dry weight) and sulphated galactans, xylans and mannans. These polymers are composed mainly of rhamnose, xylose, glucose, glucuronic acid and sulphates, with smaller amounts of mannose, arabinose and galactose [31,32]. These polysaccharides are not fully fermented by the human GM [33,34].…”

“…Furthermore, although several works investigated the effects of seaweeds in livestock gut microbiota, they are more oriented to study the effects of seaweeds in animal production and welfare. An elegant review was recently published where they can be checked [32].…”