Increased fish consumption has been suggested to improve the metabolic syndrome (MetS) and to reduce the incidence of type 2 diabetes (T2D) and cardiovascular disease (CVD) in obese subjects. While it is well documented that marine long chain polyunsaturated fatty acids (n-3 PUFA) decrease CVD risk by improving the plasma lipid profile and reducing inflammation, the beneficial effects of n-3 PUFA on glucose homeostasis and insulin sensitivity in humans remains highly controversial. Animal and human studies carried out by the group of investigators over the past 20 years have shown that fish proteins can improve the plasma lipid profile, enhance insulin sensitivity and reduce obesity-linked inflammation. The investigators also reported that a salmon protein hydrolysate reduces body fat and increases insulin sensitivity via its calcitonin content and they observed that protein hydrolysates from salmon and other fish sources reduced inflammation in visceral adipose tissue in rodents. The investigators therefore decided a few years ago to focus on the identification of bioactive peptides from fish proteins to explore the potential of increasing the efficacy of fish muscle protein hydrolysates to prevent/treat the MetS. The investigators hypothesized that it was the peptides produced from gastrointestinal digestion that were responsible for the remarkable bioactive effects of fish proteins on the MetS. The investigators have also confirmed that a small peptides fraction (SPF) from salmon protein markedly reduces the development of T2D and inflammation in a high-fat diet (HFD)-induced, obese, atherosclerosis-prone mouse LDLr knockout (KO). These findings are very promising and suggest that fish protein-derived peptides or amino acids may also explain the beneficial effects of dietary fish intake on the MetS, T2D and CVD. Additional studies are required to validate these observations, delineate the mechanisms, and assess their direct impact in human clinical trials.~Subjects will take an oral dose of 15 g of SPF or comparator per day (powder mixed with water) in the first intervention phase (6 weeks), then 7.5 g of SPF or comparator per day (powder mixed with water) in the second intervention phase (6 weeks).
The overall goal of this study is to verify the safety of 15g of salmon peptide fraction (SPF), and to test the effects on metabolic syndrome risk factors of two doses of SPF (7.5g and 15g) in overweight-obese men and women. Transcriptomic, metabolomic and metagenomic approaches will be used to study the physiological effects of SPF and to discover the potential mechanism underlying these effects.