Intensity of Salt Taste and Prevalence of Hypertension Are Not Related in the Beaver Dam Offspring Study

Salty taste test for a low-salt diet to control blood pressure

BACKGROUND

Reducing salt intake helps prevent complications of cerebrovascular disease. To help patients accept a low-sodium diet, the salty taste test is used to evaluate how much salt an individual actually consumes. The aim of this study was to help patients with hypertension reduce their salt intake by helping them recognize the difference between their subjective perception of saltiness and the objective test results.

METHODS

We enrolled workers who visited a local occupational health institution in the period from April to August 2019. Demographic and physical characteristics were recorded. Blood pressure measurement and use of medication were also recorded. A questionnaire was used to investigate whether people liked or disliked salty food, i.e., preference for saltiness, and whether they usually ate salty, normal, or fresh food, i.e., the subjective perception of saltiness. Subsequently, the taste determination kit provided by the Ministry of Food and Drug Safety was used to objectively test saltiness at various salty taste concentrations. The Ministry of Food and Drug Safety program (No. 10-093760) was used as the salty taste judgment tool.

RESULTS

A total of 86 workers were surveyed. Eleven of 18 workers (61.1%) who reported usually eating fresh food actually ate normal or salty food. Thirteen of 37 workers (35.1%) who reported eating normal food actually ate salty food. Thirteen of 31 workers (41.9%) who reported eating salty food actually ate fresh or normal food. Of 46 workers who reported disliking salty food, 14 (30.4%) actually ate salty food, while 20 (43.5%) ate normal food. The subjective perception and preference for saltiness were not significantly correlated with the objective test results (P = ​​0.085 and P = 0.110, respectively). As for the subjective perception and preference for saltiness, Cohen's weighted kappa for the taste judgment result were 0.23 and 0.22, respectively, indicating a low degree of agreement.

CONCLUSIONS

In dietary counseling to prevent cerebrovascular and cardiovascular diseases, rather than relying on the subjective perception of saltiness, a salty taste test should be performed such that people can recognize their salty food eating habits through objective evaluation.

Associations between chronic cigarette smoking and taste function: Results from the 2013-2014 national health and nutrition examination survey

We identified associations between cigarette-smoking and taste function in the U.S. NHANES 2013-2014. Adults ≥ 40 years (n = 2849, nearly half former or current smokers) rated whole-mouth and tongue-tip bitter (1 mM quinine) and salt (1 M NaCl, 0.32 M NaCl) intensities and reported smoking history (pack years, PY), dependence (time to first cigarette, TTFC) and menthol/non-menthol use. Perceived intensity on the tongue-tip averaged just below moderate for quinine and moderate to strong for 1 M NaCl. Current chronic smokers (≥ 20 PY) reported lower bitter and salty intensities on the tongue-tip (β: -2.0, 95% CI: -3.7 to -0.4 and β: -3.6, 95% CI: -6.9 to -0.3, respectively) than never smokers. Similarly, compared to never smokers, dependent current smokers (TTFC ≤ 30 min) and dependent chronic smokers (≥ 20 PY, TTFC ≤ 30 min) rated less bitter (β: -2.0, 95% CI: -4.0 to 0.1 and β: -2.9, 95% CI: -4.5 to -1.3, respectively) and salty (β: -5.3, 95% CI: -9.3 to -1.4 and β: -4.7, 95% CI: -8.6 to -0.7, respectively) intensities on the tongue-tip. Depressed tongue-tip intensity in dependent smokers (with/without chronicity) versus never smokers was significant in younger (40-65 years), but not older (> 65 years) adults. Former smokers, non-chronic/less dependent smokers, and menthol smokers were more likely to report elevated whole-mouth quinine and 1 M NaCl intensities. Tongue-tip and whole-mouth taste intensity concordance varied between smokers and never smokers-current dependent smokers were more likely to rate tongue-tip quinine and NaCl lower than their respective whole-mouth tastants (OR: 1.8, 95% CI: 1.0 to 3.1 and OR: 1.8, 95% CI: 1.1 to 2.8, respectively). In summary, these U.S. nationally-representative data show that current smoking with chronicity and/or dependence associates with lower tongue-tip intensity for bitter and salty stimuli. Smokers with greater exposure to nicotine and/or dependence showed greater risk of taste alterations, with implications for diet- and smoking-related health outcomes.

The Association between Salt Taste Perception, Mediterranean Diet and Metabolic Syndrome: A Cross-Sectional Study

Metabolic syndrome (MetS) is a widespread disorder and an important public health challenge. The purpose of this study was to identify the association between salt taste perception, Mediterranean diet and MetS. This cross-sectional study included 2798 subjects from the general population of Dalmatia, Croatia. MetS was determined using the Joint Interim Statement definition, and Mediterranean diet compliance was estimated using Mediterranean Diet Serving Score. Salt taste perception was assessed by threshold and suprathreshold testing (intensity and hedonic perception). Logistic regression was used in the analysis, adjusting for important confounding factors. As many as 44% of subjects had MetS, with elevated waist circumference as the most common component (77%). Higher salt taste sensitivity (lower threshold) was associated with several positive outcomes: lower odds of MetS (OR = 0.69; 95% CI 0.52–0.92), lower odds for elevated waist circumference (0.47; 0.27–0.82), elevated fasting glucose or diabetes (0.65; 0.45–0.94), and reduced HDL cholesterol (0.59; 0.42–0.84), compared to the higher threshold group. Subjects with lower salt taste threshold were more likely to consume more fruit, and less likely to adhere to olive oil and white meat guidelines, but without a difference in the overall Mediterranean diet compliance. Salt taste intensity perception was not associated with any of the investigated outcomes, while salty solution liking was associated with MetS (OR = 1.85, CI 95% 1.02–3.35). This study identified an association between salt taste perception and MetS and gave a new insight into taste perception, nutrition, and possible health outcomes.

Impairment of Bitter Taste Sensor Transient Receptor Potential Channel M5-Mediated Aversion Aggravates High-Salt Intake and Hypertension

Excessive salt consumption leads to cardiovascular diseases. Despite various measures designed to reduce salt intake, daily salt intake remains at a high level. Appropriate salt intake is balanced by salt taste preference triggered by epithelium sodium channel and salt taste aversion evoked by bitter taste sensor, transient receptor potential channel M5 (TRPM5). However, the behavioral mechanism of excessive salt intake remains largely elusive. In this study, wild type and TRPM5^-/- mice were applied to study the influence of high-salt administration on epithelium sodium channel/TRPM5 and the associated behavior to salt consumption. We found that long-term high-salt intake impaired the aversive behavior to high-salt stimulation but did not alter the preference to low salt in mice. The mechanistic evidence demonstrated that high-salt intake blunted the TRPM5-mediated aversive behavior to noxious salt stimulation through inhibiting PKC (protein kinase C) activity and PKC-dependent threonine phosphorylation in the tongue epithelium but did not affect the epithelium sodium channel-dependent salt taste preference. Inhibition of TRPM5 also resulted in an impaired aversive response to high salt, with reduced taste perception in bitter cortical field of mice. TRPM5^-/- mice showed a lowered aversion to high-salt diet and developed salt-induced hypertension. The impaired perception to bitter taste evoked by high-salt intake also existed in hypertensive patients with high-salt consumption. We demonstrate that long-term high-salt consumption impairs aversive response to concentrated salt by downregulating bitter taste sensor TRPM5. It suggests that enhancing TRPM5 function might antagonize excessive salt intake and high salt-induced hypertension.

The salt-taste threshold in untreated hypertensive patients

Background

The salt-taste threshold can influence the salt appetite, and is thought to be another marker of sodium intake. Many studies have mentioned the relationship between the sodium intake and blood pressure (BP). The aim of this study was to evaluate the relationship between the salt-taste threshold and urinary sodium excretion in normotensive and hypertensive groups.

Methods

We analyzed 199 patients (mean age 52 years, male 47.3%) who underwent 24-h ambulatory BP monitoring (ABPM). Hypertension was diagnosed as an average daytime systolic BP of ≥135 mmHg or diastolic BP of ≥85 mmHg by the ABPM. We assessed the salt-taste threshold using graded saline solutions. The salt-taste threshold, 24-h urinary sodium and potassium excretion, and echocardiographic data were compared between the control and hypertensive groups.

Results

The detection and recognition threshold of the salt taste did not significantly differ between the control and hypertensive groups. The 24-h urinary sodium excretion of hypertensive patients was significantly higher than that of the control group (140.9 ± 59.8 vs. 117.9 ± 57.2 mEq/day, respectively, p = 0.011). Also, the urinary sodium-potassium ratio was significantly higher in the hypertensive patients. There was no correlation between the salt-taste threshold and 24-h urinary sodium excretion.

Conclusions

The salt-taste threshold might not be related to the BP status as well as the 24-h urinary sodium excretion.

Influence of salty food preference on daily salt intake in primary care

PURPOSE

A salt preference questionnaire may be a convenient and cost-effective method for predicting salt intake; however, the influence of salt preference on daily salt intake is unclear. This study aimed at revealing the effectiveness of the salt preference question in determining the daily salt intake in primary care outpatients.

PATIENTS AND METHODS

This cross-sectional study included 1,075 outpatients (men, n=436, 40.6%) at six primary care institutions in Japan. Primary outcomes included a salty food preference assessed by using one question and a daily salt intake, assessed using early morning second urine samples. Multivariate analyses determined the relationships between the salt intake and the two salt preference levels.

RESULTS

The mean age was 67.6±14.6 years, and 594 (55.3%) preferred salty foods. The daily salt intake was 12.3±4.0 g per day and 11.4±3.7 g per day in the salt preference and nonsalt preference groups, respectively (P<0.001). A salt intake <10 g per day was consumed by 169 (28.5%) and 181 (37.6%) patients (P=0.001), respectively, and <6 g salt per day was consumed by 28 (4.7%) and 26 (5.4%) patients (P=0.606), respectively. The patients who preferred salty foods consumed a significantly larger amount of salt per day than those who did not prefer salty foods (β coefficient, 0.621; 95% confidence interval [CI], 0.146-1.095). There was no difference in the number of patients who consumed <10 g salt per day (adjusted odds ratio [ad-OR], 1.29; 95% CI, 0.99-1.69) or <6 g salt per day (ad-OR, 1.39; 0.90-1.69) between the groups.

CONCLUSION

Preference for salty foods was positively associated with daily salt intake. However, daily salt intake was not always appropriate, even in the patients who did not prefer salty foods. Behavioral interventions for salt restriction after an assessment of daily salt intake are necessary for primary care patients, regardless of their preference for salty foods.