Comparative effects of glucose-lysine versus glucose-methionine Maillard reaction products consumption: in vitro and in vivo calcium availability.

The influence of glucose-lysine and glucose-methionine Maillard reaction products (MRPs) on calcium availability was studied in rats and in Caco-2 cells. Equimolar glucose/lysine and glucose/methionine mixtures (40% moisture) were heated (150 degrees C, 30 or 90 min) to prepare samples (GL30, GL90, GM30, and GM90, respectively). For 21 days, the rats were fed the AIN-93G diet (control group) or diets containing separately 3% of the heated mixtures (GL30, GL90, GM30, and GM90 groups, respectively). In the last week of the trial, a calcium balance was performed. On day 21, the animals were sacrificed and their livers and femurs removed for analysis of calcium levels. The GL30 and GM30 samples and the corresponding raw mixtures were used for Caco-2 cells experiments. Fecal excretion of calcium decreased and urinary elimination increased in the GM30 and GM90 groups. In accordance, increased calcium transport in Caco-2 cells was found in the presence of the GM30 sample, compared with the raw sample. Bone calcium concentration was lower among the animals consuming MRP diets, compared with the control group. The possible long-term effects of MRP intake on calcium deposition in the bone should be further studied to ascertain the implications on related diseases.