| Background and purpose:Hypertension is the leading risk factor for cardiovascular and cerebrovascular diseases and has become an important public health problem in the world.The incidence of hypertension has increased year by year,causing huge socioeconomic and medical burdens.In 2016,Lewington S et al.analyzed the cohort of nearly 500,000 people in China and found that up to one-third of adults in China were suffered from hypertension.The rates of diagnosis,treatment,and control in Chinese hypertensive patients are quite lower than those in Western populations and are significantly associated with higher mortality.It is estimated that around 750,000 cases of cardiovascular disease deaths are caused by non-compliance of hypertension control in China,and is has become the first cause of cardiovascular death in China.Numerous epidemiological studies have shown that high-salt diet is an important risk factor for high blood pressure and is closely related to cardiovascular events such as atherosclerosis,stroke,and myocardial infarction.Reducing salt intake can effectively decrease the potential risks for hypertension and other cardiovascular events.China has great and traditional food cultures,and the salt added in home-made cooking foods is the main source of salt for the residents.Reducing the amount of salt usage will greatly affect the taste of food and thus affect the effectiveness of salt restriction.Taste is the most important determinant of what and how much we eat.Earlier studies by Fallis N et al.had confirmed that compared with normotensive people,salt taste sensitivity of hypertensive patients is significantly reduced and the salt taste supra-threshold is significantly higher.At the same time,patients with lower salt taste sensitivity in the hypertensive population showed higher blood pressure levels.Despite a large amount of evidences show that the daily salt intake in the world far exceeds the physiological requirement(which is about 3g),it is still unclear what causes the high salt intake behavior and its molecular basis.Studies have confirmed that high-salt diet can lead to a decrement of salt taste sensitivity,but whether it will cause the changes in bitter taste sensitivity and thus reduce aversion reactions of high salt and promote high-salt eating habits is still unclear.The purpose of this study was to compare the differences in bitter taste sensitivity,salt taste sensitivity,and blood pressure levels between hypertensive patients with low-salt intake or high-salt intake,by testing their taste sensitivity and estimating the daily salt intake through 24-hour urinary sodium excretion;and to clarify the influence of the high salt intake habit on the sensitivity of bitter taste.By comparing with normal subjects,to explore the change in bitter taste sensitivity of hypertensive patients and its correlation with salt intake,blood pressure,etc.,as well as the features of hypertension-related target organs damage under different bitter taste sensitivity status.This study investigates the change in bitter taste sensitivity and its relationship with salt intake and cardiac remodeling in hypertensive patientsand try to provide a new target for gustatory intervention for salt restriction strategies.Subjects:From February 2017 to August 2017,82 inpatients with primary hypertension of the Department of Hypertension and Endocrinology of the Third Affiliated Hospital of Army Medical University were enrolled.Among them,39 were male and 43 were female,and the average age was 55.8±10.0 years old.From July 2017 to March 2018,31 volunteers consist of family members or cares of patients were recruited in the Department of Hypertension and Endocrinology,the Third Affiliated Hospital of Army Medical University.Among them,11 were male and 20 were female,and the average age was 54.5±9.4 years old.Research methods:The hypertension group met the definition of hypertension in the "Chinese Hypertension Prevention Guidelines 2010"(below).Definition of hypertension: When hypotensor is not used,blood pressure is measured three times in different days,systolic blood pressure is ?140 mmHg and/or diastolic blood pressure is ?90 mmHg;or patients with previous history of hypertension and is now using hypotensor,even their blood pressure is lower than 140/90 mmHg,also were diagnosed as hypertension.Exclusion criteria: age less than 18 years old;secondary hypertension;upper respiratory tract infections,chronic rhinitis,sinusitis,mouth ulcers or inflammation;diseases affecting water and sodium metabolism;history of brain trauma,history of brain surgery,trigeminal nerve pain,intracranial occupancy,etc.;Cardiovascular diseases such as severe arrhythmia,acute coronary syndrome;Pregnant or lactating women;Pulmonary disease;Severe liver disease;Mental illness;Type 1 diabetes,special type of diabetes;Cancer patients;drugs such as narcotic drugs and hormones are being used.Examination items: collect patients' general information,such as age,gender,course of hypertension,smoking history,past history,current disease history,blood pressure,height,weight,body mass index;collect blood lipids,renal function,liver function,glycosylated hemoglobin,24 h urine biochemistry,echocardiography.Taste sensitivity test: different concentrations of taste test solutions(0,25,50,75,and 100umol/L quinine solution;10,30,50,70,500,750,1000,and 1500mmol/L sodium chloride solution)were prepared for the test.(1)The test was conducted in a quiet,ventilated,odor-free room.The subjects' mouths were rinsed with deionized water before and after tasting the solution,and they should not swallow the test solution.(2)The test solution prepared before the test was tasted,and the subject was tested from low concentration to high concentration.Before the test,the patient did not know any taste and concentration of the solution.(3)About 5ml of the different concentrations of quinine test solution was tasted.Each time the taste was taken,it was required to pause in the oral cavity for about 5 seconds.After the tasting,the Subject was required to inform the practitioner of the taste characteristic of the solution.Test carry on when no taste is detected by tasting 0mmol/L quinine solution.When the subject correctly answers the taste of the test solution,the test is repeated with the same concentration solution again to ensure accurate results.If a test subject needs to try again,try the same concentration solution again.Before and after tasting a solution,their mouths were rinsed with deionized water.The two tests are separated by about one minute,(4)record the lowest concentration of The quinine solution which can be recognized as the subject's bitter taste sensitivity.(5)After the bitter taste test was completed,the salt taste sensitivity test was performed 3 minutes later with 10 mmol/L,30 mmol/L,50 mmol/L,and 75 mmol/L sodium chloride solution.The salt taste sensitivity test procedure is similar to the bitter taste sensitivity test.(6)After the salt taste sensitivity test was over,mouthwash was performed again and salt taste supra-threshold was tested 3 minutes later.the test was also started from a lower concentration(start from 500mmol/L).About 5ml of different concentrations of sodium chloride solution was tasted,each time the subject needs to keep the solution about 5 seconds in the oral cavity before spits it out.After the tasting,the subject needs to answer a question "Do you think this solution is too salt to Tolerate," if the subject answered "intolerable"(Or similar answers),the current concentration of sodium chloride solution was used as his/her salt taste supra-threshold,if the subject answered "tolerable",the next concentration of sodium chloride solution was tested,Until his/her answer was "intolerable";then the test was stopped and the last tested concentration was used as his/her salt taste supra-threshold.Statistical analysis and mapping were performed by using SPSS 22.0 and GraphPad Prism 7.0 software.All measurement data were tested for normal distribution and homogeneity of variance.The comparison between two groups of samples was performed using an independent sample t-test.The composition ratio and grade data were tested using chi-square test.A bilateral P<0.05 was considered statistically significant.Result:According to the lowest concentration of quinine solution that tasted bitter,subjects were divided into bitter taste sensitive group(can recognize bitter taste with concentration of quinine solution ?50umol/L)and bitter taste insensitivity group(can only recognize bitter taste with concentration of quinine solution ?75umol/L).According to the perception of the lowest concentration of salt solution,subjects were divided into salt taste sensitive group(can recognize ?30mmol/L sodium chloride solution),salt taste insensitive group(can only recognize ?50mmol/L sodium chloride solution).According to the intolerable concentration of the high concentration salt solution,subjects were divided into low salt supra-threshold group(cannot tolerate 500mmol/L sodium chloride solution),and high salt supra-threshold group(can tolerate 500mmol/L and above concentration of sodium chloride solution).According to the amount of daily salt intake,subjects were divided into high salt group(salt intake ? 9g/day),and low salt group(salt intake<9g/day).1.Compared with the low-salt hypertensive patients,the high-salt hypertensive patients have lower sensitivity to bitter taste(P=0.017),lower salt taste sensitivity which is represented by the lower salt taste perception(P=0.011)and higher salt taste supra-threshold(P=0.001),the differences were statistically significant.2.Based on the sensitivity of bitter taste,all hypertensive patients enrolled were divided into: bitter taste sensitive group(n=40,male 17 cases,mean age 54.8±10.4 years),and bitter taste insensitive group(n=42,male 22 cases,mean age 56.8±9.5 years).Compared with the bitter taste-insensitive group,the salt intake of hypertensive patients in the bitter taste-sensitive group was reduced by approximately 2.2 g/day(7.9 ± 4.0 g/day vs.10.1 ± 4.0 g/day,P=0.0137).At the same time,we observed the dual effects of salt intake and bitter taste sensitivity on blood pressure.We found that although there was no significant difference,patients with high salt and low sensitivity to bitter taste had higher systolic blood pressure than patients with high salt intake and high bitter sensitivity(systolic blood pressure: 150±23 mmHgv.140±23 mmHg,P=0.265.Diastolic pressure: 80±15 mmHg vs.78±17 mmHg,P=0.719).The above results suggest that the sensitivity to bitter taste is closely related to salt intake and may be related to the increase of blood pressure.3.Compared with the normal blood pressure group,hypertensive patients had a decreased sensitivity to bitter taste(P=0.019)and decreased sensitivity to salt perception(P=0.021).The difference was statistically significant,but there was no statistical difference in salt taste supra-threshold.4.A comparison of different groups of bitter taste sensitivity in hypertensive patients showed that the thickness of interventricular septum was significantly increased in hypertensive patients in the bitter taste insensitivity group(11.1±1.4 mm vs 10.5±1.3 mm,P=0.007),and the left ventricular mass index was also significant increased(99.2 ± 22.4 g/m2 vs 92.2 ± 19.5 g/m2,P = 0.049).Conclusion:1.Sensitivity to bitter taste and salt taste decreased in hypertensive patients with long-term high-salt diet.Reduced bitter taste sensitivity is associated with a significant increase in salt intake.It suggests that changes in bitter taste sensitivity play an important role in high salt intake and improving taste may help to reduce salt intake.2.Compared with normotensive persons,hypertensive patients have a reduced bitter taste sensitivity and salt taste sensitivity.Hypertensive patients with insensitivity to bitter taste have heavier cardiac damage,suggesting that there may be an interaction between them,and it is necessary to further research. |
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