Estimating Glycemic Index of Rice-Based Mixed Meals by Using Predicted and Adjusted Formulae

The estimation of glycemic index(GI) of rice-based mixed meal either by using predicted GI(GI_(pred)) or adjusted GI(GI_(adj)) formula is unclear.This study aimed to determine the glycemic response of rice in rice alone or mixed meals and to identify the appropriate formula for estimating the GI of rice-based mixed meals.The glycemic responses produced by the rice alone(red rice,fragrant white rice or parboiled rice) and the rice-based mixed meals(fried red rice,fried fragrant white rice or fried parboiled rice) which provided 25 g available carbohydrate were assessed in 11 healthy individuals.To determine the measured GI(GImeasured) of rice alone and rice-based mixed meals,participants underwent three repeated tests of a reference food(Glucolin~?).Tests were performed in random order on nine separate visits after an overnight fasting for at least 8 h.Capillary glucose at baseline(0 min),15,30,45,60,90 and 120 min from starting the meals was assessed and used to determine the incremental area under the curve(iAUC_(120)).The agreement between GImeasured and the estimation formulae(GI_(pred) or GI_(adj)) were determined using Bland-Altman analysis.The iAUC_(120) after consuming rice alone was significantly higher than the rice-based mixed meals except for fried fragrant rice,which was comparable to the rice alone(P > 0.05).The GI_(measured) values of rice were categorized as medium(61 for parboiled rice,67 for fragrant white rice,and 68 for red rice).GI_(pred)(r = 0.40,P < 0.01) and GI_(adj)(r = 0.41,P < 0.01) were significantly correlated with iAUC_(120).The agreement between GI_(measured) and GI_(adj) is apparent suggesting the usefulness of GI_(adj) in estimating meal GI of rice-based mixed meals.

Brewers' rice modulates oxidative stress in azoxymethanemediated colon carcinogenesis in rats

AIM: To investigate the mechanistic action of brewers' rice in regulating the Wnt/nuclear factor-kappa B(NF-κB)/Nrf2-signaling pathways during colon carcinogenesis in male Sprague-Dawley rats.METHODS: Male Sprague-Dawley rats were randomly divided into the following five groups(six rats in each group):(G1) normal,(G2) azoxymethane(AOM) alone,(G3) AOM + 10%(weight(w)/weight(w)) brewers' rice,(G4) AOM + 20%(w/w) brewers' rice, and(G5) AOM + 40%(w/w) brewers' rice. They were intraperitoneally administered 15 mg/kg body weight of AOM in saline once weekly over a twoweek period and treated with an American Institute of Nutrition(AIN)-93 G diet containing 10%, 20%, and 40%(w/w) brewers' rice. The m RNA levels of glycogen synthase kinase 3β(GSK 3β), β-catenin, key inflammation markers, nuclear factor E2-related factor 2(Nrf2), and heme oxygenase-1(HO-1)-dependent transcriptional activity were assessed by quantitative real-time polymerase chain reaction analyses. The colon superoxide dismutase, malondialdehyde, and nitric oxide levels were also analyzed to assess the antioxidant effect of these treatments. The results were analyzed using one-way analysis of variance(ANOVA), and a P value of < 0.05 was considered significant.RESULTS: The overall analyses demonstrated that the dietary administration of brewers' rice in AOM-induced rat colon carcinogenesis resulted in the transcriptional upregulation of GSK 3β, inducible nitric oxide synthase(i NOS), Nrf2, and HO-1. We discovered that the dietary administration of brewers' rice downregulated the β-catenin and NF-κB m RNA levels. A significant reduction in β-catenin expression was found in the groups administered with 20%(0.611 ± 0.034) and 40%(0.436 ± 0.045)(w/w) brewers' rice compared with that of the group treated with AOM alone(1.000 ± 0.064)(P < 0.05). The NF-κB expression was significantly lower between the AOM-alone group(1.000 ± 0.048) and those groups fed with diets containing 10%(w/w) brewers' rice(0.255 ± 0.022), 20%(w/w) brewers' rice(0.450 ± 0.045), or 40%(w/w) brewers' rice(0.541 ± 0.027)(P < 0.05). Brewers' rice improved the antioxidant levels, indicating that brewers' rice can enhance effective recovery from oxidative stress induced by AOM.CONCLUSION: Our results provide evidence that brewers' rice can suppress colon cancer via the regulation of Nrf2 expression and the inhibition of the Wnt/NF-κB signaling pathways.