Marine algal polysaccharides may help prevent CVD via gut microbiota modulation: China review
Recent studies have found a link between gut microbiota and CVD, the number one cause of death globally. In China, for instance, around 40% of deaths are attributed to CVD — higher than the death rate from other diseases, including cancer. This has led to research into MAPs, which are natural sources of diverse bioactive compounds whose pharmaceutical activities include antioxidant, anti-inflammatory, immunomodulatory and anti-diabetic effects.
It should be noted that most MAPs are not utilised in the upper gastrointestinal tract but are fermented by intestinal flora. As such, a number of CVD studies have focused on the connection between MAPs and intestinal microbiota.
Based on this, researchers at Guangdong Ocean University and Shantou University conducted a review to emphasize the key action through which MAPs have been found to affect CVDs and how they can be applied to prevention strategies against CVDs.
From the gut to the heart
Gut microbiota dysbiosis is typically linked to gastrointestinal disorders, which then affect immune response. According to emerging evidence, there is likely “an interaction between the gut microbiome and CVDs” such as hypertension, peripheral artery disease, myocardial fibrosis and heart failure.
Additionally, numerous studies have reported changes in gut bacteria composition and diversity in CVD sufferers. For instance, obesity (a CVD risk factor) is involved in the development of dysbiotic gut micriobiota, while the growth of the bacterium Akkermansia muciniphila in the gut has been found useful in preventing metabolic syndromes like type 2 diabetes and obesity.
The review included several Chinese studies that supported these findings. One study reported that Enteromorpha clathrata polysaccharides “dramatically elevated the relative abundance of Akkermansia muciniphila in the gut”, as well as that of two other species of bacteria — Bifidobacterium spp. and Lactobacillus spp. The latter two are widely used probiotics that have been proven to improve and modulate intestinal flora and help to prevent CVD through cholesterol removal.
Another study found that alginate oligosaccharide regulated intestinal microbiota in mice that had been placed on a high-fat diet to induce gut dysbiosis, and resulted in improved fat metabolism and reduced inflammation. Other researchers in China also reported that the polysaccharide Undaria pinnatifida markedly lowered fasting blood glucose levels, alleviated glucose intolerance and improved insulin resistance in diabetic rats by promoting the growth of beneficial bacteria.
MAP-ping out a prevention strategy
The aforementioned evidence provides a good indicator that, like oligosaccharides and other polysaccharides, MAPs have the potential to help prevent CVD by way of gut microbiota modulation. The review noted the short-chain fatty acids (SCFAs) — which improve gut health by supporting intestinal barrier integrity and protecting against inflammation — were the main products of MAPs fermentation by the large intestine’s intestinal flora.
It added that SCFA regulation of blood pressure and increased lipid metabolism were possibly direct effects of CVD risk modulation, and that according to in-vitro and in-vivo experiments, MAPs were a “good source for increasing SCFA concentration”.
Furthermore, the review posited that MAPs could be instrumental in reconstructing the intestinal micro-environment, restoring gut microbiota composition and potentiating heart failure management. In addition, intestinal microbiota can ferment undigested MAPs for their growth and the production of SCFAs.
Apart from MAPs gut health benefits, they are also a “potential sustainable source for the production of functional foods or nutraceutical products for preventing or treating CVD”. This is due to marine algae being much more abundant than other ocean resources, as well as its own abundance of nutrients that include polysaccharides, proteins, peptides, amino acids, mineral salts, lipids and polyphenols.
Numerous studies have demonstrated that MAPs’ cardio-protective effects include normalised lipid metabolism, decreased oxidative stress and improved immune response. The review stated that the relationship between MAPs and intestinal flora could offer fresh insights into MAPs’ beneficial impact on CVD.
It further said that in-depth studies in future should support MAPs being developed as “a potential prevention strategy for CVD” by targeting gut health, adding that the significant differences in gut microbiota composition necessitated a detailed structural characterisation of MAPs and their cardio-protective effects.
“A Comprehensive Review of the Cardioprotective Effect of Marine Algae Polysaccharide on the Gut Microbiota”
Authors: Kit-Leong Cheong, et al.