Fucoidan is a polysaccharide isolated from brown algae. It has multiple healing properties, such as antitumor and antioxidant benefits. Although there are many reports on the prebiotic effects of polysaccharides on the host, there are few that relate the results of Fucoidan on biochemical blood indices, gut microbiota, and metabolic function in healthy hosts. The gut microbiota is a complex microbial ecosystem whose homeostasis is essential for host health, and studies have linked the gut microbiota to many diseases, including intestinal inflammation, metabolic syndrome, and cancer.
Thus, I would like to share the results of the study “Microbiome-Metabolomics Reveals Prebiotic Benefits of Fucoidan Supplementation in Mice” by Jingyi Yuan et al.
First, they applied 16S rRNA gene amplicon sequencing and LC-MS/MS metabolomics to assess changes in gut microbiota and metabolite profiles as mice were under fucoidan treatment over ten weeks. (See Figure. A1)
In this study, fucoidan supplementation reduced mice’s serum TG and TC levels. Higher TG and TC levels represent impaired lipid metabolism. High TC and TG levels increase the risk of pancreatitis and cardiovascular disease. Additionally, correlation analysis showed that Lactobacillus gasseri and Lactobacillus animals were negatively correlated with TG levels. These two species were also significantly enriched with Fucoidan. Lactobacillus gasseri reduced weight gain and improved glucose tolerance in rats by promoting energy expenditure. Gasseri supplementation also significantly decreased visceral fat weight. The TG concentration in the liver of KK-Ay mice (an animal model of type 2 diabetes) was fed a high-fat diet. It was shown that the decrease in TG levels after fucoidan administration may be associated with the enrichment of Lactobacillus gasseri and Lactobacillus animalis populations.
Tryptophan produced by gut microbes is a key signaling molecule in host-microbe interactions and may contribute to metabolic homeostasis, including the gut-endocrine system and glucose metabolism. In the above-mentioned study, the concentrations of tryptophan-related metabolites indoleacetic acid, 3-indoleacetic acid, and 5-hydroxytryptamine in mouse feces were significantly increased after fucoidan supplementation, and the attention of these three metabolites was considerably more significant than those of lactophenol. Thus, there was a positive correlation between populations of Bacillus animalis and Lactobacillus gasseri. Lactobacillus reuteri has been reported to improve constipation by regulating serum 5-hydroxytryptamine levels in patients with functional constipation.
The study also showed that Indole acrylic acid can be absorbed through the intestinal epithelium, enter the systemic circulation, and exert antioxidant and anti-inflammatory effects. In addition, 5-hydroxytryptamine has been shown to alleviate intestinal inflammation, such as dextran sodium sulfate-induced colitis in mice. In addition, indoleacetic acid and 5-hydroxytryptamine reduced proinflammatory cytokines in macrophages and inhibited cell migration toward chemokines. This study suggests that fucoidan supplementation may ameliorate host injury and inflammatory responses by enhancing tryptophan-related metabolites, supported by Lactobacillus enrichment in mice.
On the other hand, Histidine is an essential amino acid during childhood and plays a vital role in host homeostasis. This study found that after fucoidan supplementation, Histidine concentration in the feces of mice increased by 61.77% compared to the control group. Histidine-related Metabolites Histidine dipeptides, such as carnosine, are considered scavengers of reactive carbonyl species (RCS) that have a potential pathogenic role in obesity and related metabolic disorders. Essentially, the study observed that Histidine is associated with malignant tumor progression. A histidine-rich diet enhanced the inhibitory efficiency of low-dose methotrexate on solid tumors in mice and reduced methotrexate toxicity.
Branched-Chain Amino Acids (BCAAs), such as leucine, isoleucine, and valine, are essential in regulating energy homeostasis, nutrient metabolism, gut health, and immune responses in animal and human subjects. As per the results, Fucoidan significantly increased the content of leucine, isoleucine, and valine when the fucoidan supplement was taken.
Moreover, previous studies have shown that the leucine- and valine-related products 3-hydroxybutyrate and β-aminoisobutyrate play a role in signaling molecules, including activation of protein synthesis and insulin secretion. Leucine supplementation stimulated muscle protein synthesis. It also activates the mTOR signaling pathway that regulates gene transcription and protein synthesis, which in turn regulates cell proliferation and immune cell differentiation. Hence, it also plays an essential role in tumor metabolism.
In conclusion, Fucoidan employs prebiotic effects in healthy mice through lipid regulation and reduced endotoxemia. It could be related to their ability to modulate the gut microbiota of species such as Lactobacillus animalis, Lactobacillus gasseri, and Lactobacillus reuteri—Metabolomics such as tryptophan-related metabolites. (See Figure A8) Through this study, it is discovered that Fucoidan can provide a healthy dietary strategy.
Source: J. Mar. Sci. Eng. 2021, 9(5), 505; https://doi.org/10.3390/jmse9050505