Effects Of Brown Rice Products On Glucose And Lipid Metabolism And Insulin Resistance In Rats Fed With High Fat And High Sugar

Objective:To compare the changes of basic components,phenols,and dietary fiber contents and properties of brown rice products obtained by different processing methods and to investigate the effects of brown rice products on glucose and lipid metabolism and insulin resistance in rats fed high-fat and high-sugar diets and to explore possible mechanism.To provides a scientific basis for the prevention of metabolic disorders of glucose and lipids and the occurrence of insulin resistance,and also provides a theoretical basis for guiding scientific production,reasonable diet,and scientific consumption.Methods:Part 1: Comparison of the basic components of four kinds of rice products and their nutritional components.Indica brown rice after milling two times to obtain white rice,white rice and indica brown rice as raw material.Different rice processing methods were used to prepare brown rice noodles(half-dried process),brown rice instant porridge(extrusion processing technology),brown rice and white rice(hot processed steamed).The contents of moisture,ash,total protein,crude fiber,total starch,amylose and amylopectin were measured with the corresponding national standard.Extraction and determination of rice products free total phenols and bound content and compare its antioxidant activity.The dietary fiber of rice products was extracted by enzymatic chemical method,its antioxidant activity and physical properties were determined.The content of the fiber was determined by enzyme gravimetric method. Part 2: Effects of brown rice products on glucose and lipid metabolism and insulin resistance in rats fed with high fat and high sugar Sixty healthy SPF 4-5-week-old male SD rats were randomly divided into 6 groups.10 rats in each group: 1 Basic group;2 High-fat and high-sugar group;3~6 groups were fed with high-fat and high-sugar diets containing white rice,brown rice,brown rice noodles and brown rice instant porridge.Rats in each group eat and drink freely for 14 weeks.The body weight and food intake of rats were measured every week.Blood glucose was monitored before the experiment and on the 4th,6th,8th,10 th and 14 th weekend using the Roche glucose meter.OGTT experiments were performed on rats at the 8th week.The concentration of fasting insulin(FINS)was detected by enzyme-linked immunosorbent assay and its insulin resistance index and insulin sensitivity index were evaluated.The colorimetric method was used to determine the contents of ALT,AST,UA,BUN,TC,TG,HDL-C,LDL-C,and hepatic glycogen.The hepatic lobe was fixed with10% formalin and the histopathological changes were observed with Suspermine-Eosin staining.Part 3 :Mechanism of the effects of brown rice products on glycometabolism and insulin resistance in rats fed with high fat and high sugar T-AOC,T-SOD,GSH-Px,CAT activities and MDA levels in serum and liver homogenates were determined by colorimetry.The levels of serum interleukin-6,tumor necrosis factor,leptin,adiponectin and resistin were detected by ELISA.Result:Part 1: Comparison of the basic components of four kinds of rice products and their nutritional components.1.Basic components:The ash content of brown rice(1.40%),brown rice noodles(1.27%)and instant porridge(1.55%)is twice than that of white rice(0.71%).The crude fiber content of brown rice(1.31%),brown rice noodles(1.35%)and instant porridge(1.24%)is about 4 times than that of white rice(0.35%)(P<0.05).The amylose contents of white rice and brown rice were significantly higher than brown rice noodles and instant porridge(P<0.05).2.The content of total phenols: brown rice noodles(64.05mg/100g)>brown rice instant porridge(63.95mg/100g)>brown rice(50.70mg/100g)>white rice(20.27mg/100g).The content of total flavonoids: brown rice instant porridge(736.50mg/100g)>brown rice noodle(642.27mg/100g)>brown rice(581.17mg/100g)>white rice(186.81mg/100g).3.The total antioxidant capacity of the phenolic extracts of brown rice products were higher than that of white rice,and the order of eliminating DPPH and ABTS + free radicals was: brown rice instant porridge>brown rice noodle>brown rice>white rice(P<0.05).There was a significant correlation between the content of total phenols and flavonoids and the scavenging capacity of free radicals(P<0.01).The content of total free phenols and total flavonoids had a good correlation with the total antioxidative activity(r= 0.904,r= 0.824).4.The content of TDF,SDF and IDF of brown rice products were higher than those of white rice,and the contents of TDF and IDF were higher in brown rice(P<0.05).The content of SDF in brown rice instant porridge was higher(P<0.05).The characteristics of the comparison: holding power: brown rice/brown rice noodle>white rice/brown rice instant porridge(P<0.05).Swelling power: white rice/brown rice>brown rice instant porridge>brown rice noodle(P<0.05).Adsorption of fatty acids of fasting porridge dietary fiber is about 2 times than that of rice(P<0.05).Antioxidant activity: brown rice dietary fiber were higher than white rice;Clearing DPPH capacity of brown rice instant porridge is more than 2 times than that of rice noodles,more than 2 times than that of rice.The removal ABTS + capacity of instant porridge and rice noodles is 3 to 4 times than that of rice.Part 2: Effects of brown rice products on glucose and lipid metabolism and insulin resistance in rats fed with high fat and high sugar1.General condition: After 4 weeks,the body weight of rats fed the high-fat,high-sugar group and the three kinds of brown rice products was significantly higher than that of the basic group(P<0.05).However,the weight of white rice group was higher than that of basic group eight weeks ago(P<0.05),but the difference was not statistically significant after eight weeks(P>0.05).The food intake of five high fat and sugar diet rats was significantly lower than that of the basic group(P<0.05),while that of the brown rice noodle group was not significantly different from the basic group after 9 weeks(P>0.05).Food intake was the lowest in high fat and white rice group(P<0.05).After six weeks,the feed-to-weight ratio of five groups of high fat and sugar group was significantly lower than that of the basic group(P<0.05).The weight of brown rice instant porridge group higher than the other four model groups after 11 weeks(P<0.05).2.Oral glucose tolerance test: Blood glucose reached the highest after 30 minutes in six groups of rats.The blood sugar of the basic group dropped to 6.61 mmol/L after 60 minutes and the rate of decline was the fastest.The high fat and sugar group and the white rice group dropped slowest(P<0.05).After 2h,the blood glucose level of the basic group returned to normal level.The blood glucose levels of five high fat and sugar group were higher than those of the basic group(P<0.05).Compared with the AUC of the basic group rat,the other five groups were significantly higher(P<0.05).The AUC of the high fat and sugar group and the white rice group was slightly higher than that of the brown rice product group.3.Blood glucose and liver glycogen content: The blood glucose level in high fat and sugar group,white rice group and brown rice group in the fourth week and the tenth week were higher than those in the basic group,the brown rice noodle group and the brown rice instant porridge group(P<0.05).In the results of glycogen analysis,the content of hepatic glycogen in the basal group,brown rice noodle group and brown rice instant porridge group was significantly lower than that of the high fat and sugar group,the white rice group and the brown rice group(P<0.05).4.Fasting insulin content: The fasting insulin levels and insulin resistance index of brown rice fast food porridge group and the basic group was significantly lower than the other four groups(P<0.05).The insulin sensitivity index of brown rice instant porridge group and the basic group is relatively high,brown rice noodles slightly lower than the first two groups,followed by brown rice group,the lowest is white rice and high fat and sugar group(P<0.05).5.Blood lipid content :The content of TC in high fat and sugar group was higher than that in basic group and four kinds of products group(P<0.05).The LDL-C content of six groups was not statistically significant(P>0.05).Compared with the basal group,the content of HDL-C in brown rice instant porridge group was lower,and those of the other four groups was the lowest(P<0.05).6.Visceral index: The ratio of spleen to body of rats in the high-fat,high-sugar group and white rice group was significantly higher than that in the basic group,and the brown rice products were between the first three groups(P<0.05).The liver weight and liver/body ratio of the five high-fat and high-sugar diet groups were significantly higher than that of the basic group(P<0.05).The liver-to-body ratio was highest in the white rice group and the high-fat and high-sugar group.The visceral fat and visceral fat index of rats fed brown rice porridge were significantly lower than those of the other four groups(P<0.05).7.General anatomy of the liver: Compared with the basic group,the livers of the rats fed with high-fat and high-sugar diet had different degrees of hyperplasia,the elasticity weakened and fatty liver appeared.The histomorphology also showed five groups of rat liver cells exhibited varying degrees of steatosis,with the most severe being the white rice group,followed by the brown rice group,the brown rice noodle group and the brown rice instant porridge group showing very slight steatosis.Part 3 : Mechanism of the effects of brown rice products on glucose and lipid metabolism and insulin resistance in rats fed with high fat and high sugar1.Oxidative stress parameters: the difference of serum T-AOC level in six groups of rats was not significant(P>0.05).The MDA content of high fat and sugar group and white rice group was significantly higher than the basic group and brown rice products(P<0.05).The contents of T-SOD in brown rice instant porridge group and basic group were higher than those in the other four groups(P>0.05)and those in white rice group and high fat and sugar group were the lowest(P<0.05).The contents of CAT and GSH-PX in serum of high fat and sugar group were lower than the other five groups(P<0.05).2.Inflammatory factors: The content of IL-6 in brown rice products and basal group was lower than those in white rice group and high fat and sugar group(P<0.05)and lower than the other four groups(P<0.05). 3.Fatty factor: the difference of serum leptin levels of the six groups did not show statistical significance(P>0.05).The level of adiponectin in the brown rice group was the highest,followed by the brown rice noodle group and brown rice instant group,the lowest is the basal group,high-fat and high-sugar group and white rice group(P<0.05).The content of resistin in the five groups fed high fat and sugar diet groups was higher than that of the basic group,the white rice group was the highest,followed by the high fat and sugar group and finally the three brown rice products group(P<0.05).Conclusion:1.The antioxidant activity,the content of phenols as well as the ability of dietary fiber to absorb oil of brown rice products are higher than the white rice.Brown rice instant porridge and brown rice noodles compared to rice products has higher phenolic content,higher water-soluble dietary fiber and dietary fiber has a strong ability to absorb oil and free radical scavenging capacity.2.Long-term intake of high-fat and high-sugar diets will lead to disorders of lipid metabolism,increased body weight and visceral fat,decreased appetite,insulin resistance,abnormal lipid metabolism,and fatty liver.3.Three kinds of brown rice products can improve the state of glucose and lipid metabolism disorders and insulin resistance in rats caused by high-fat and high-sugar diet to varying degrees,but the effect on body weight is not obvious.Compared with brown rice,brown rice instant porridge and brown rice noodles can significantly improve glucose and lipid metabolism disorders,insulin resistance and fatty liver state,while refined white rice does not have an improved effect.4.Brown rice products may regulate their glucose and lipid metabolism and improve their insulin resistance by reducing the inflammatory response of rats,reducing their oxidative stress and resistin levels and increasing adiponectin levels.