Several attempts to decrease sugar demand by introducing stevioside as a sugar substitute in children's food products have been made, but safety issues were concerned. This exploratory study investigated the effects of stevioside low dose (SL), high dose (SH) and low dose with inulin (SL + I) for 12 weeks on the body weight, organ relative weight, hematological and biochemical parameters and enzyme activities of young male rats. The SL dose used in this study was 15 mg kg(-1) per day and the SH dose was 100-fold the low dose. Enormous similarities in most parameters were observed with no significant differences between SL, SL + I and control except in the lipid profile. Total lipid reduction in SL and SL + I and significant high-density lipoprotein increase in SL + I were observed, which may be considered as clinically beneficial. Significant decreases in serum tartrate-resistant acid phosphatase activity were also observed in all treatments. Treatment with SH caused significant changes in all investigated toxicological parameters. The results indicated that, although the SL dose was higher than the stevioside temporary accepted daily intake (5.0 mg kg(-1) body weight), no toxicological effects were observed in SL or SL + I on body weight, organ relative weight, hematological and biochemical parameters or enzyme activities investigated in this study, whereas stevioside high dose (1500 mg kg(-1) per day) may be considered as a toxic dose for the same biological parameters in young male rats. However, the effects of SL, SH and SL + I on serum tartrate-resistant acid phosphatase activity need more investigation.

Over the years, there has been concern about the changes taking place in heated oils and the effects on individuals consuming them. The present study investigated the effects of a diet containing thermally oxidized soybean oil (TO) or TO supplemented with probiotic Bifidobacteria (TO+Pro) on the serum lipid profile and oxidative stress biomarkers of male rats. The data showed several indicators of oil deterioration after thermal processing, including high levels of % free fatty acid (FFA; 15-fold), acid value (AV; 14-fold), peroxide value (8-fold), p-anisidine value (AnV; 39-fold), total oxidation value (TOTOX; 19-fold), thiobarbituric acid-reactive substances (TBARS) value (8.5-fold), and trans-FA (TFA) isomers (2.5-fold) compared to the control. The rats that were fed a diet containing TO showed a significant (p < 0.05) decrease in body weight gain, food efficiency values, and liver weight. Furthermore, the total cholesterol and low-density lipoprotein (LDL) levels were increased, while the high-density lipoprotein (HDL) level was decreased in blood serum samples. High levels of TBARS, superoxide dismutase (SOD), and glutathione reductase (GR) activities were also detected in the livers, kidneys, testes, and brains of rats. Interestingly, a diet containing TO+Pro restored all biological parameters to their control values. The present data suggested that Bifidobacteria may ameliorate the serum lipid profile and oxidative stress biomarkers that are generated in animals that are fed a TO diet.

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The effect of green tea (GT) and green tea with olive oil (GT+OL) as antioxidants on the formation and mutagenic activity of heterocyclic aromatic amines (HCAs) extracted from beef shawerma, grilled chicken and fried beef liver was examined. HCAs were extracted by blue rayon, analyzed as spiked and unspiked samples with high-performance liquid chromatography and its mutagenic response was assessed by Sallmonela typhimurium 100 in the Ames test. Surprisingly, GT and GT+OL augmented HCAs measured in beef shawerma and grilled chicken but total HCAs measured in GT+OL were less than GT treatment. Both treatments altered the HCA profile as imidazoquinoline type became the most abundant. In control and GT+OL fried beef liver no HCAs were detected, but Trp-P1 was detected in GT treatment. Generally, the mutagenic response of HCAs measured in GT+OL was less than GT in beef shawerma and grilled chicken. However, the mutagenic response of control and 2% GT+OL fried liver was negative. These data suggest that GT concentrations used in this study may induce free radical formation during the Millared reaction due to its pro-oxidative effect, which augmented the HCAs formed and its mutagenic response. In order to optimize both safety and quality of our diets, more need to be done to fully understand the risk of HCAs in food.

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