The Experimental And Clinical Research Of Effect Of Oligofructose On Essential Hypertension

BackgroundEssential hypertension (EH) as one of the important risk factors resulting cardiovascular diseases has high morbidity in China nowadays. It has been suggested that in our country 2,330,000 people die of cardiovascular events caused by hypertension. Prehypertension is an American classification for where a person's blood pressure is elevated above normal but not to the level considered to be hypertension, which blood pressure was read with a systolic pressure from 120 to 139 mm Hg or a diastolic pressure from 80 to 89 mm Hg. As soon as people were considered as prehypertension, non-drug therapy should be started to prevent development of hypertension. EH and prehypertension both have significant correlations with increase of crude death rate and mortality rate of cardiovascular diseases in our country. According to the epidemiology of EH that so many people have no awareness of their elevated blood pressure, non-drug treatment should be initiated when they were in prehypertension period.The therapy of EH include anti-hypertension drugs and non-drug treatment, which consists mainly of healthy dietary replacement and lifestyle change programme. Trials of lifestyle change programmes have shown worthwhile improvements in blood pressure. But the researches were rare on dietary treatment improving blood pressure. Dietary fiber is the indigestible portion of plant foods that is readily fermented in the colon into gases and physiologically active byproducts, which can improve body health. It can protect gut health and prevent colon cancer, decrease blood glucose and adjust lipid to lower morbidity of coronary heart diseases and protect caridiovascular system. American Hypertension Guideline suggests hypertension patients should choose Dietary Approaches to Stop Hypertension (DASH), which means they should have more fruits, vegetables and grain in daily dietary to increase dietary fiber intake. Prebiotics, as one kind of soluble dietary fiber, is a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health. Prebiotics were proved to be effective in obesity, diabetes and dyslipidemia. Oligofructose(OFS), one of the most popular prebiotics, was widely used in food industry as an ingredient for milk and biscuits, etc. Part1Effects of oligofructose on blood pressure and lipids in hypertension rat model induced by high-fructose dietaryObject:To prove the feasibility of hypertension rat modeling by means of high-fructose feeding. To observe the effects of oligofructose on blood pressure, blood lipids and blood glucose in hypertension rats by determining daily intake, weight, fat, blood glucose, blood lipids and insulin level.Methods:Thirty male Sprague-Dawley rats, weighting 110-120g, were the randomly assigned three groups included 10 rats:control group (standard feed, C group), high fructose group (high fructose feed, F group) and oligofructose group (high fructose feed with 10% oligofructose, OFS group). Weekly body weight and daily food intake were measured for 12 weeks. At the end of feeding period, the rats were sacrificed by anesthetizing with sodium pentobarbital (7ml/100g of body weight i.p.) after 12h of food deprivation. Hyperinsulinemic euglycemic clamp technique was performed to evaluate insulin sensitivity. Blood was collected and stored at-80℃for analysis. Blood plasma was stored at-20℃for fasting blood glucose, blood lipid (TG, TC, LDL, HDL) determination by automatic biochemical analyzer; plasma insulin and visfatin determination by ELISA; antioxidant enzyme activity and oxidation products level by colorimetry. The abdominal adipose tissues (perirenal, epididymal) were carefully removed using scissors and weighed for visceral fat index accouting and visfatin expression determination. Samples of kidney were kept in 10% formalin for pathological histology study.Results:Weight of rats in F group and OFS group were significant lower than in C group and the difference between these two groups were not statistically significant. Blood pressure increased in F group and OFS group, and BP in OFS group was lower than in F group(P<0.05). There were no difference of total feed intake, blood glucose and fasting insulin level. GIR in F and OFS group decreased significantly compared with C group, whereas GIR in OFS group was higher than in F group. Visceral fat index (VFI) of rats in F group and OFS group were significant higher than in C group and VFC of rats in OFS group was lower than in F group(P<0.01). Total triglyceride, total cholesterol and LDL in F group and OFS group were higher than in C group(P<0.05). TC and HDL had no significant difference in F group and OFS group. Plasma visfatin in F group was higher than in C group and OFS group. Visceral visfatin in F group was highest and in OFS group was higher in three groups. Visfatin was highly expression in F group and OFS group, but expression in OFS group was lower than in F group.Conclusion:1. High-fructose feeding can successfully construct hypertension rat model, which was characterized with increased blood pressure and insulin resistance. This modeling method was efficient with low death rate.2. Oligofructose has no significant effect on food intake and body weight.3. Oligofructose can improve blood pressure in hypertension rats.4. Oligofructose can decrease visceral fat accumulating and inflammatory factor level, which may improves insulin sensitivity in hypertension rats. It has effect on kidney protection which may acts by enhancing antioxidant capacity.5. Oligofructose is beneficial to blood lipid in hypertension rats.Part 2Effects of oligofructose supplementation on blood pressure and lipid metabolism in prehypertensive people:a randomized, controlled prospective trialObject:To observe the effect of oligofructose(OFS) supplementation on blood pressure and lipid metabolism in prehypertensive subjects.Methods:A randomized, double-blinded, placebo-controlled trial was designed in the present study. A total of 140 adults aged 20 to 70 years with prehypertension were recruited from the community in Shanghai. All the participants signed the informed consents. Subject received anti-hypertension drugs were also excluded because of the interference of medication effect on blood pressure. All the participants were randomly assigned by using computer-generated random numbers to either receive 20g OFS per day (OFS group, n=70) or receive maltodextrin (control group, n=70) in a blinded fashion for 12 weeks. During the period a manual based self-management programme was developed for all participants in order to homogenize the lifestyle. Compliance was monitored using serial contemporaneous food and lifestyle trackers. The participants were interviewed at 0 w,6 w,12 w during the trial. Blood samples were collected at 0 w and 12 w. Changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded as primary study outcomes. Secondary outcomes including blood total cholesterol, triglyceride and anthropometric data werecollected before and at the end of the treatment period.Results:Randomization was successful and there were no significant differences between groups in any of the baseline measures. No severe adverse reaction presents during the study period. In the 6th wk,3 participants quited the trial in control group and 2 in OFS group. In the 12th wk,1 quited and 2 failed to blood tests in control group.3 quited and 2 failed to blood tests in OFS group.The measured outcomes showed more beneficial changes in OFS group. At the end of intervention, SBP and DBP was significant lower in OFS group than in control group. The decrease value of SBP in OFS group was higher than in control group. Waist circumference and BMI in OFS group were lower than in control group during 2nd follow-up. Participants in OFS group also had significantly lowered blood total cholesterol, triglyceride and LDL in OFS group than in control group.Conclusion:1. Oligofructose is safe used as beneficial additional to usual diet.2. Oligofructose supplementation leads to a significant reduction in blood pressure in prehypertension subjects.3. Oligofructose can decrease blood cholesterol and triglyceride in prehypertension subjects, which may protect cardiovascular system.4. Oligofructose decreases waist circumference and BMI which may benefit to hypertension prevent and treatment.