Investigation of the methylglyoxal scavenging kinetics of different food matrices under simulated intestinal conditions

Studies on the Reaction of Dietary Methylglyoxal and Creatine during Simulated Gastrointestinal Digestion and in Human Volunteers

The reactive 1,2-dicarbonyl compound methylglyoxal (MGO) is consumed with food and its concentrations decrease during digestion. In the present paper, the reaction of MGO with creatine, arginine, and lysine during simulated digestion, and its reaction with creatine during the digestion in human volunteers, was studied. Therefore, simulated digestion experiments with a gastric and an intestinal phase were performed. Additionally, an intervention study with 12 subjects consuming MGO-containing Manuka honey and creatine simultaneously or separately was conducted. Derivatization with o-phenylenediamine and HPLC–UV was used to measure MGO, while creatine and glycated amino compounds were analyzed via HPLC–MS/MS. We show that MGO quickly reacts with creatine and arginine, but not lysine, during simulated digestion. Creatine reacts with 56% of MGO to form the hydroimidazolone MG-HCr, and arginine reacted with 4% of MGO to form the hydroimidazolone MG-H1. In the intervention study, urinary MG-HCr excretion is higher in subjects who consumed MGO and creatine simultaneously compared to subjects who ingested the substances separately. This demonstrates that the 1,2-dicarbonyl compound MGO reacts with amino compounds during human digestion, and glycated adducts are formed. These contribute to dietary glycation products consumed, and should be considered in studies investigating their physiological consequences.

Modulation of 1,2-Dicarbonyl Compounds in Postprandial Responses Mediated by Food Bioactive Components and Mediterranean Diet

Glycoxidative stress with the consequent generation of advanced glycation end products has been implied in the etiology of numerous non-communicable chronic diseases. During the postprandial state, the levels of 1,2-dicarbonyl compounds can increase, depending on numerous factors, including characteristics of the subjects mainly related to glucose metabolism disorders and nutritional status, as well as properties related to the chemical composition of meals, including macronutrient composition and the presence of dietary bioactive molecules and macromolecules. In this review, we examine the chemical, biochemical, and physiological pathways that contribute to postprandial generation of 1,2-dicarbonyl compounds. The modulation of postprandial 1,2-dicarbonyl compounds is discussed in terms of biochemical pathways regulating the levels of these compounds, as well as the effect of phenolic compounds, dietary fiber, and dietary patterns, such as Mediterranean and Western diets.

Safety and efficacy of a feed additive consisting of guanidinoacetic acid for all animal species (Alzchem Trostberg GmbH)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of guanidinoacetic acid (GAA) when used as nutritional additive in feed and water for drinking for all animal species. The FEEDAP Panel concludes that GAA at 1,200 mg/kg complete feed is safe for chickens for fattening, piglets and pigs for fattening. This concentration in complete feed would correspond to maximum concentrations in water of 600 mg GAA/L for chickens for fattening, piglets and pigs for fattening. The Panel is not in a position to conclude on a safe level of GAA in laying/reproductive birds. In the absence of data on ruminants and salmonids, the FEEDAP Panel cannot conclude on the safety of GAA for all animal species. There is no concern on consumer safety resulting from the use of GAA in feed for poultry and pigs at the proposed conditions of use. The limited data do not allow to conclude on the safety for the consumer when the additive is used in feed for ruminants or fish. GAA is not toxic by inhalation, it is not an irritant to skin and eyes, and it is not a dermal sensitiser. The FEEDAP Panel concludes that the use of GAA as feed additive is not expected to pose a risk to the environment. The use of the additive under assessment in animal nutrition at the proposed conditions of use has the potential to be efficacious in all growing avian, Suidae and ruminant (except for preruminants) species; in growing fin fish other than salmonids and in frog. It is not possible to conclude on the efficacy of the additive in other species, and in reproductive animals.