I use this paper as an excuse to eat honey. My second and third references indicate that methylglyoxal mostly doesn't survive digestion.
Curr Aging Sci. 2010 Dec;3(3):239-41.
Honey, health and longevity.
Cooper RA, Fehily AM, Pickering JE, Erusalimsky JD, Elwood PC.
Abstract
Honey is a broad spectrum antimicrobial agent which can enhance wound healing. A beneficial effect in cancer has been shown in cell cultures and in animal studies and a number of further nutritional and physiological effects of relevance to health and function have been shown for honey. A representative sub-sample of 665 men within the Caerphilly Cohort kept a weighed dietary record for seven days. Risk factors for vascular and other diseases in 41 men who recorded eating honey suggest that these men were on the whole healthier than the 624 men who had not recorded honey consumption. All-cause mortality during 25 years of follow-up was considerably lower in the men who had consumed honey, the hazard ratio, adjusted for a number of possible confounding factors, being 0.44 (95% confidence limits 0.23, 0.86; P<0.017). Because of the small number of subjects and of deaths in this study, further data from other large cohorts will be required before any effect upon mortality and other health effects of honey consumption can be adequately evaluated.
PMID: 20735343
J Agric Food Chem. 2013 Oct 30;61(43):10253-60.
Metabolic transit of dietary methylglyoxal.
Degen J, Vogel M, Richter D, Hellwig M, Henle T.
Abstract
Methylglyoxal (MGO) is responsible for the pronounced antibacterial activity of manuka honey, in which it may reach concentrations up to 800 mg/kg. As MGO formed in vivo is discussed to play a role in diabetic complications, the metabolic transit of dietary MGO was studied within a 3 day dietary recall with four healthy volunteers. Determination of MGO in 24 h urine was performed with GC-MS after derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, and D-lactate was quantified enzymatically. Following a diet virtually free from MGO and other glycation compounds, a defined amount of MGO (500 μmol in manuka honey) was administered in the morning of day 2. Renal excretion was between 0.1 and 0.4 μmol/day for MGO and between 50 and 220 μmol/day for D-lactate. No influence on excretion of both compounds was observed following administration of MGO. To investigate the stability of MGO under physiological conditions, a simulated in vitro gastrointestinal digestion was performed with MGO-containing honey. After 8 h of in vitro digestion, only 5-20% of the initial methylglyoxal was recovered. This indicates that dietary MGO is rapidly degraded during the digestion process in the intestine and, therefore, exerts no influence on the MGO level in vivo.
PMID: 23451712
J Agric Food Chem. 2013 Mar 6;61(9):2140-5.
Influence of in vitro simulated gastroduodenal digestion on methylglyoxal concentration of Manuka ( Lectospermum scoparium ) honey.
Daglia M, Ferrari D, Collina S, Curti V.
Abstract
Manuka honey (MH) is a functional food that shows in vitro antimicrobial activity and to which wound healing properties, positive effects on oral health, and beneficial properties during the treatment of gastrointestinal infection diseases and upper gastrointestinal dyspepsia are assigned. The antibacterial activity of MH is mainly due to its high concentration of methylglyoxal (MGO), a highly bifunctional alkylating agent that can induce rapid nonenzymatic modifications of proteins. The aim of the present study was to investigate the influence of in vitro simulated gastric and gastroduodenal digestion on MGO content of MH. To this aim commercial MH samples, with different MGO concentrations, were submitted to digestion, and MGO was determined before and after digestion by a validated RP-HPLC-DAD method. Moreover, the role of MGO in causing carbonylation of the digestive proteins and influencing their enzymatic activities was investigated. The results showed that after digestion MGO concentration decreases because it reacts with digestive enzymes by carbonylating their free amino groups. Nevertheless, carbonylation of pepsin and pancreatin does not influence their physiological activity and therefore does not seem to interfere with the digestion process.
PMID: 23406199