Influence of rice with different amylose contents on postprandial glycemic response / Journal of Rural Medicine

Objective: Clinical studies suggest that maintaining a lower postprandial glycemic response is important for improvement and prevention of metabolic syndrome and type 2 diabetes mellitus. Amylose, an ingredient in many food grains, is a major factor for the lowering of postprandial glycemic and insulinemic response. The aim of the present study was to determine the influence of rice with different level of amylose on postprandial glycemic and insulinemic response in mice and humans.Materials and Methods: The two types of rice used in the study contained 29 wt% (high amylose rice) or 17 wt% (low amylose rice) amylose. In mice and humans, postprandial glycemic and insulinemic responses were measured and then the area under the response curves of both rice groups were compared.Results: In mice, comparisons of postprandial glycemic response showed high amylose rice was lower than that for low amylose rice in all time points. Notably postprandial glycemic responses for high amylose rice at 15, 30, 45 and 60 min were significantly lower (19%, 31%, 16% and 17% respectively). The area under the glycemic response curve for high amylose rice was a remarkably 16% less than for the low amylose rice. In humans, postprandial glycemic response at 30 min and insulinemic response at 60 min for high amylose rice were significantly lower than for low amylose rice (15% and 40% lower, respectively). Furthermore, general linear measurement multivariate analysis after adjustment for eating time and hemoglobin A1c at baseline showed that postprandial glycemic response at 30 and 60 min and insulinemic response at 60 min, and the area under the glycemic response curve for high amylose rice were significantly lower than for low amylose rice in human.Conclusion: The higher amylose content of the rice lowered the postprandial glycemic and insulinemic response, demonstrating the potential to prevent or improve metabolic syndrome and type 2 diabetes mellitus.

Enriched n-3 polyunsaturated fatty acids of dense LDL subfraction in Japanese women with small, dense LDL categorized by non-denaturing gradient gel electrophoresis / Journal of Rural Medicine

;Small, dense low density lipoprotein (LDL) has been suggested to be highly atherogenic as a result of their low-binding affinity to LDL receptors, their prolonged plasma half-life and low resistance to oxidative stress. Although marine n-3 polyunsaturated fatty acids (PUFAs) have beneficial effects for the prevention of cardiovascular diseases, there is little information on detailed fatty acid composition in LDL particles. In the present study, LDL subfractions were isolated from the plasma of 45 clinically healthy Japanese women by density gradient ultracentrifugation using a light fraction of 1.025-1.034 g/ml (LDL-I), an intermediate fraction of 1.034-1.044 g/ml (LDL-II), and a dense fraction of 1.044-1.060 g/ml (LDL-III). A clear relationship between the frequency of fish intake and increases in plasma n-3 PUFAs was apparent. Although plasma n-3 PUFAs in women with small-sized LDL using non-denaturing gradient gel electrophoresis (GGE) did not show a significant difference, n-3 PUFAs and n-3 PUFAs/n-6 PUFAs in dense LDL-III subfraction increased in the small-sized LDL group using GGE, compared to those with buoyant LDL particles. The result of enriched n-3 PUFAs in dense LDL subfraction suggests that n-3 PUFAs may help prevent atherosclerosis in the arteries of Japanese women with small-sized LDL.

Dietary Antioxidants for Prevention of Cardiovascular Disease / Journal of Rural Medicine

The traditional Japanese diet with its high intake of fruits and vegetables that are rich in antioxidants is believed to effectively ward off cardiovascular disease. Oxidative stress, related to reactive oxygen and nitrogen species produced by aerobic organisms, is responsible for the pathogenesis of most chronic diseases. Oxidative low density lipoprotein (LDL) is thought to play a key role in the pathogenesis of early atherosclerosis. There has been increasing interest in antioxidant substances derived from edible plants. It has been suggested that the measurement of LDL antioxidant activity is physiopathologically more important and informative for screening antioxidant activity to prevent atherosclerosis than other methods. We assessed by LDL oxidation assay the antioxidant characteristics of various edible plants from rural areas. The mulberry (Morus alba L.) leaf showed comparatively high antioxidant activity. We identified the antioxidant compounds and investigated compound levels in the mulberry leaf and found the antioxidant activity of mulberry leaves to be mainly attributable to quercetin 3-(6-malonylglucoside) (Q3MG). Dietary consumption of mulberry leaves and/or Q3MG may enhance resistance to oxidative modification of LDL and attenuated atherosclerotic lesion development. However, the outcome of intervention trials suggested that a single antioxidant had little effect on the risk of developing cardiovascular disease. The synergic effect of certain combinations may determine outcome. We need to widen our understanding of the synergic effect of diets and nutrient-gene interactions related to nutrient/disease risk.