| Objective:With the aggravation of aging,the incidence of cardiovascular diseases is increasing,and high salt intake is the main risk factor for hypertension.Due to poor dietary salt restriction compliance in the elderly,it may be an effective salt restriction measure to change the salt taste sensitivity of the elderly.Animal experiments have shown that capsaicin can affect the central circuit of salt taste in mice.By changing the neural processing of salt taste in the brain,the salt preference of mice can be significantly reduced as well as salt taste perception,thus the salt taste sensitivity can be enhanced,finally reduce the daily salt intake.The purpose of this study was to observe the correlation between salt taste and salt intake of the elderly in northeast China and explore whether capsaicin can enhance salt taste sensitivity in the elderly by adding capsaicin to salt solution.Methods: From April 2017 to September 2018,115 elderly inpatients aged 60-95 years old in the department of cardiovascular medicine of the first affiliated hospital of China medical university were selected as the study subjects.The urine of 90 patients was completely retained for 24 h that was measured for 24 h sodium to calculate the salt intake.Salt taste test was used to determine the salt threshold and salt preference of the elderly with different concentrations of Na Cl solution.Then the salt solution added with 0.5μmol/L of capsaicin(Na Cl+CAP)was used to determine the salt preference again,and the increase of salt taste sensitivity was observed by the decrease of salt preference.Meanwhile,the paired difference test of Na Cl+CAP salt solution was conducted on subjects with salt threshold≥50mmol/L to observe whether Na Cl+CAP salt solution increased the subjects’ perception of salt taste.Results: A total of 115 subjects met the inclusion and exclusion criteria,including 73 males and 42 females.The average age was 79.4±9.5 years.The salt threshold of the elderly was more than 50mmol/L,a total of 53 cases(46.1%).The preference of salt was mostly 75mmol/L and 100mmol/L,with a total of 66 cases(57.4%).The salt threshold of 50mmol/L,30mmol/L and 10mmol/L showed statistical differences in age,history of hypertension,malnutrition risk and decline in daily living ability(P<0.05),and the salt preference of 50-100mmol/L and 150-250mmol/L also showed statistical differences in age,history of hypertension,malnutrition risk and decline in daily living ability(P<0.05).The median level of 24 h sodium of 90 patients was 89.2(64.9-113.7)mmol/24 h,and the corresponding salt intake was 7.3(5.8-9.8)g/d.There were statistically significant differences in salt intake among subjects aged60-70,71-80 and >80(p<0.05).The salt intake of the elderly is higher than the 6g/d salt intake standard recommended by China’s guidelines,and the salt uptake compliance rate is less than 50%.Spearman rank correlation analysis showed no correlation between salt threshold,salt preference and salt intake(p>0.05).The median levels of salt preferences before and after the addition of capsaicin were 100(75-150)mmol/L and 75(50-150)mmol/L,respectively,with statistically significant differences in salt preferences(P<0.01).There was a statistically significant difference in the number of people with decreased salt preference between the groups of50-100mmol/L and 150-250mmol/L(p<0.05).Through paired difference test,it was found that among the subjects with a salt threshold of 50mmol/L,19(63.3%)indicated that Na Cl+CAP solution had a salinity intensity greater than that of Na Cl solution alone.Among the subjects with a salt threshold of 75mmol/L,17(73.9%)indicated that Na Cl+CAP solution had a stronger salt taste than Na Cl solution alone.The salt threshold of 50mmol/L and 75mmol/L showed no statistically significant difference in the salt taste perception of Na Cl+CAP solution between the two groups(p>0.05).Conclusion: The salt threshold of the elderly was more than 50mmol/L,Salt preference was 75mmol/L and 100mmol/L of the elderly in northeast China.People with higher salt threshold and salt preference were older,had a higher risk of malnutrition,were less capable of daily living,and lacked self-care and the ability to live alone.The salt intake of the elderly was >6g/d,and the salt uptake compliance rate of men and women was less than 50%.In this study,there was no correlation between salt preference and salt intake.In the elderly,Salt threshold and salt preference are not simple methods for assessing salt intake in elderly patients with cardiovascular disease.0.5μmol/L capsaicin can significantly increase the perception of salt taste,reduce salt preference and increase salt taste sensitivity.Adding spicy supplements such as capsaicin to foods represents a new type of lifestyle intervention that can be applied to the elderly,so it may be an effective alternative to reducing salt intake in the elderly. |
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