Dietary interventions have a considerable impact on the prevention, progression and treatment of obesity and insulin resistance, through a range of mechanisms including intestinal microbiome modification. In fact, the microbiome has been proposed as a potential therapeutic target for a wide range of pathologies, including obesity and insulin resistance.
Diet supplementation with fish-derived oil containing omega 3 fatty acids has been shown to possess beneficial effects in diabetes and obesity and studies have indicated that fish collagen may exert a beneficial effect on diet-induced obesity. Yet, the contribution of fish extracts on the gut microbiome has not been investigated, and neither has the combination of fish collagen with fish-derived extracts on type 2 diabetes, obesity, and the microbiome.
In the present study, a murine model of high-fat diet (HFD)-induced obesity and type 2 diabetes was utilized to examine the effects of fish-derived nutritional supplements on obesity and diabetes and determine changes in the gut microbiome.
Mice were fed for nine weeks with a high-fat diet supplemented with 5% w/w fish-derived supplements. Cod Powder (CP) and Fish Complex (FC), which consists of Codfish, Coalfish and Haddock, and contains higher concentrations of the health-promoting minerals Calcium, Phosphorus and Zinc, were tested individually or in combination.
Fecal samples were collected, DNA was extracted, and a metagenome analysis was performed by 16S rRNA gene sequencing analysis.
A Principal Component Analysis (PCoA) was conducted based on the identified OTUs, to assess genetic clustering of the different diet groups. Overall, 1,463,319 quality filtered sequences were generated that were assigned to 7137 unique OTUs.
According to the PCoA, three distinct groups were formed; one including the lean diet-fed mice (ND), one including the groups supplemented with collagen-containing diets (collagen from the Seagarden company in Norway), and one tight cluster containing the high-fat diet-fed, FC, CP and FC+CP groups.
The PCoA showed significant differences between the lean (ND) and HFD groups. Interestingly, the groups supplemented with collagen-containing diets clustered together, in great distance from the other complexes, pointing to a differentiated bacterial niche within the gut microbiome.
Although FC and FC+CP promoted insulin sensitivity in high-fat diet-fed mice, they exhibited no profound differences in the gut microbiome as demonstrated by the identified OTUs. The same applied for mice fed with CP.
The ND-fed group was also found to be the most diverse group in terms of species richness, counting on average 1303 unique OTUs, whereas groups supplemented with collagen-containing diets were proven to be the least diverse, counting on average 731 unique OTUs.
The researchers conclude that nutritional supplements containing Fish Complex (FC), Fish Complex combined with Cod Powder (FC + CP), or Cod Powder combined with Collagen (CP + C,) improved glucose intolerance, independent of abdominal fat accumulation, in a mouse model of diet-induced obesity and type 2 diabetes. In addition, collagen-containing supplements distinctly modulate the gut microbiome in high-fat induced obesity in mice.
They say their results suggest that fish-derived supplements suppress diet-induced type 2 diabetes, which may be partly mediated through changes in the gut microbiome. Thus, fish-derived supplements and particularly the ones containing fish collagen have potential beneficial properties as dietary supplements in managing type 2 diabetes and metabolic syndrome via modulation of the gut microbiome.
"Herein, we demonstrate that fish-derived nutritional supplements suppress glucose intolerance in a model of high-fat diet-induced obesity and type 2 diabetes in mice and specifically nutritional supplements containing fish complex, fish complex combined with cod powder and cod powder combined with collagen.
"In addition, nutritional supplements containing fish-derived collagen modulated the gut microbiome in obese mice, inducing colonization of beneficial bacteria, known to have beneficial properties in suppressing metabolic inflammation and diabetes. Thus, our results suggest that fish-derived extracts may suppress type 2 diabetes and that this action may be partly due to collagen-induced modulation of the gut microbiome."
Source: Marine Drugs
Axarlis, K.; Daskalaki, M.G.; Michailidou, S.; Androulaki, N.; Tsoureki, A.; Mouchtaropoulou, E.; Kolliniati, O.; Lapi, I.; Dermitzaki, E.; Venihaki, M.; Kousoulaki, K.; Argiriou, A.; Marsni, Z.E.; Tsatsanis, C.
"Diet Supplementation with Fish-Derived Extracts Suppresses Diabetes and Modulates Intestinal Microbiome in a Murine Model of Diet-Induced Obesity"