According the study the creatine and the methylhistidine in the serum; and urine are the potential biomarkers of cod and salmon intake; a randomizing study in adults with overweight or obesity. To identify the biomarkers to assess participants compliance; in an intervention study with high intake of cod or salmon, comparing to a fish free diet.
The risk of developing type 2 diabetes and cardiovascular disease have in some studies been showing to be reducing; whereas others have finding no association; and some have shown that fish intake may increase the risk for developing type 2 diabetes. the long-chain n-3 PUFAs can be measured in isolated phospholipids from serum or plasma or in isolated red blood cells.
The potential biomarkers
However, these methods are time consuming, expensive, require a relatively large sample volume; and can only be used as biomarkers for intake of fatty fish. Compounds associated with fish muscle proteins measured in blood or urine may be better biomarkers for assessing intake of both lean and fatty fish. By investigating the use of plasma and urine concentrations of trimethylamine N-oxide, creatine, 1-methylhistidine and 3-methylhistidine as biomarkers of fish or fish protein intake and these results demonstrating that rats fed cod protein or salmon fillet had higher urine concentrations of TMAO, creatine.
The primary outcome of the present study was changes in serum and urine concentrations of TMAO, creatine, 1-MeHis and 3-MeHis after a weekly intake of 750 g fillet from either cod or salmon for 8 weeks. But the secondary outcomes were changes in amino acids and amino acid metabolites measuring in the serum and urine. The efects of high intake of cod and salmon fllets on four potential biomarkers of fsh intake, that is, TMAO, creatine, 1-MeHis and 3-MeHis, in serum and urine from adults with overweight/ obesity.
Metabolites in serum and urine
The study investigating the efects of high intake of cod and salmon fllets on the amounts of free amino acids; and amino acid metabolites in serum and urine. Reliable biomarkers of dietary intake are valuable for assessing compliance in clinical trials; where participants are responsible for administering the intervention themselves.
However, the increasing serum arginine concentration after salmon intake is in line with fndings in obese; where the most pronounced diference in amino acids; was an almost six times higher concentration of circulating arginine in them fed salmon comparing to other fed control diet; possibly as a consequence of better renal function; and thus higher arginine production in proximal tubule comparing to controls.