Elsevier

Nutrition

Volume 30, Issue 6, June 2014, Pages 690-695
Nutrition

Applied nutritional investigation
Effects of smell loss (hyposmia) on salt usage

https://doi.org/10.1016/j.nut.2013.11.003Get rights and content

Abstract

Objective

Smell loss (hyposmia) inhibits flavor perception and influences food intake. To compensate for flavor loss, some patients with hyposmia appear to increase salt usage. The purpose of this study was to compare self-reported salt usage in patients with hyposmia with that in normal volunteers.

Methods

Salt usage was compared in 56 patients with hyposmia but with normal taste function with that in 27 normal volunteers. Salt usage was formulated with respect to 1) a standard quantitative salt intake scale, 2) salt addition related to food intake, 3) intake of foods and beverages with high salt content, and 4) salt intake related to presence or absence of hypertension.

Results

Eighteen (32%) of the 56 patients self-reported increased salt usage; they were labeled “increased users.” The other 38 hyposmic patients (68%) did not report increased salt usage; they were labeled “non-changers.” Increased users estimated their salt usage rose an average 2.8 times that experienced before their hyposmia onset. They also reported adding salt to their food before tasting it and ate more highly salted foods than did the non-changers. Salt usage was not increased further among increased users with hypertension but was increased further among non-changers with hypertension.

Conclusions

Salt usage is increased among some patients with hyposmia presumably to enhance flavor perception to compensate for diminished flavor perception related to loss of smell.

Introduction

Salt intake can activate neural, endocrine, paracrine, and vascular mechanisms that have the potential to increase arterial pressure, induce hypertension, and play a role in induction of cardiovascular disease (CVD) [1]. Because “taste loss” or decreased flavor perception is a common complaint among patients with smell loss (hyposmia) [2], the question of whether or not these individuals exhibit an increased salt preference or salt appetite is of importance as there may be as many as 21 million people in the United States with hyposmia [3].

To our knowledge, there are few reported data relating salt intake among patients with hyposmia. There are studies reporting that salt intake may decrease after olfactory bulbectomy in sheep [4] or in patients as they age [5], [6], [7], although other investigators did not find this latter event to occur [8]. Many studies, however, have reported that sodium deprivation in humans [6], [9] or in animals [10], [11] enhances intake and preference for sodium solutions and enhances the appeal of reduced sodium foods. Restricting exposure to salty foods has been reported to enhance the appeal of reduced sodium foods [12]. Genetic factors related to salt taste [13], [14] and the finding of specific salt receptors [15] have also allowed a greater physiological perspective on salt intake behaviors. Patients with smell loss have been previously reported to use larger quantities of salt, thereby increasing the risk for developing hypertension [16]. Odors have been reported to increase salt intensity by as much as 25% [17], suggesting that loss of odor perception may be associated with decreased perception of salt intensity.

We have observed a common, recurrent event among patients evaluated at The Taste and Smell Clinic in Washington, D.C., which suggested that hyposmia might be an important sensory abnormality altering salt usage. Patients with this symptom commonly said they increased their use of table salt and exhibited a profound craving for salty foods after the loss of smell. This increased salt usage appeared to occur without any consistent abnormality in taste, per se. At first glance, this seemed surprising because salt taste bears no direct relation to loss of smell. However, patients with hyposmia complained of a decreased ability to obtain flavor from food and said they increased salt usage as a way to compensate. In this way, they said, the additional salt gave more “taste” or flavor to otherwise perceived bland food. To test the validity of these observations, we quantitated the amount of salt reportedly consumed by patients with hyposmia and measured their use of table salt and the frequency of their consumption of salty foods.

We also studied the incidence of hypertension in these patients. Indeed, these latter studies were related to reports that hypertensive patients preferred more highly salted fluids than controls [18], [19], [20], were less sensitive to the taste of salt [21], and thereby consumed more salt [22]. There is considerable literature relating salt intake to hypertension. Although the association between salt intake and hypertension is not clear-cut and the mechanisms underlying this relationship are unclear, several aspects of this relationship have been emphasized in recent years including genetic, renal pathophysiological, and sensory factors [23], [24]. With respect to the latter aspect, salt taste sensitivity was initially considered to play a role in controlling salt consumption in animals [25] and humans [22]. Some investigators hypothesized that hypertensive individuals consumed more salt because they could not taste it as well as individuals with normal blood pressure [21], [26], [27], however, other studies did not agree with these results [8].

Section snippets

Participants

Participants in the study were 97 consecutive patients with hyposmia and 27 normal volunteers (control group). The patients were evaluated at The Taste and Smell Clinic in Washington, D.C. for taste and/or smell dysfunction [2]. The 56 patients selected for this study all had hyposmia (v.i.) and normal taste acuity (vide infra). The 41 patients excluded from the study either did not exhibit hyposmia (e.g., they had either hypogeusia or some form of dysgeusia or dysosmia [2], [28], [29]) or had

Results

Eighteen (32%) of the 56 patients reported increased salt use at the time they were evaluated for their hyposmia. These patients were labeled “increased users” to differentiate them from the majority of patients (68%) who did not report an increase in their salt usage. They were labeled “non-changers.”

Increased users estimated that their salt usage increased over a range from two to five times that before hyposmia onset with an estimated mean of 2.8.

The total salt score of increased users was

Discussion

The results of this study confirm our clinical observations that some patients with hyposmia (with normal taste acuity) increase their use of salt and consumption of salty foods after loss of smell. These patients had high salt scores, frequently salted their foods before tasting, frequently added salt to their food at the table, rated their salt use as moderate to heavy, and frequently consumed salty foods.

The mechanism(s) of this increased salt usage in the face of normal taste acuity is

Conclusion

Increased salt usage occurs in about one-third of patients with hyposmia putatively due to a compensatory mechanism by which adding more salt to food and eating more salt-laden foods increases their ability to obtain more food flavor.

Acknowledgment

The author acknowledges D. Mattes-Kulig for her major assistance in performance of this study.

References (40)

  • R.J. Contreras

    Salt taste and disease

    Am J Clin Nutr

    (1978)
  • F.C. Catalanotto et al.

    Preference for NaCl in the spontaneously hypertensive rat

    Life Sci I

    (1972)
  • R.I. Henkin et al.

    An open to label controlled trial of theophylline for treatment of patients with hyposmia

    Am J Med Sci

    (2009)
  • R.I. Henkin et al.

    Taste and smell function in chronic disease: A review of clinical and biochemical evaluation of taste and smell dysfunction in over 5000 patients at The Taste and Smell Clinic in Washington, DC

    Am J Otolaryngol

    (2013)
  • T.A. Kotchen et al.

    Salt in health and disease—a delicate balance

    New Engl J Med

    (2013)
  • R.I. Henkin

    Evaluation and treatment of human olfactory dysfunction

  • R.I. Henkin

    Report on a survey on smell in the US

    Olfact Rev

    (1987)
  • P.B. Grzegorczyk et al.

    Age-related differences in salt taste acuity

    J Gerontol

    (1979)
  • J. Mojet et al.

    Taste perception with age: Generic or specific losses in supra-threshold intensities of five taste qualities?

    Chem Senses

    (2003)
  • M. Bertino et al.

    Sodium depletion increases rats' preferences for salted food

    Behav Neurosci

    (1988)
  • Cited by (21)

    • The need for sensory nutrition research in individuals with smell loss

      2022, Clinical Nutrition Open Science
      Citation Excerpt :

      One way H/A individuals compensate for flavor loss is by enhancing the tastes (i.e. sweet, sour, salty, bitter, umami) in their food [16]. In particular, many studies indicate that individuals self-report adding more salt to their foods after losing their sense of smell [17,42], and develop a preference for salty [16,36] and sweet foods [36]. Another way H/A individuals compensate for flavor loss is by adding spices or hot sauce to their foods to enhance the chemesthesis aspect of flavor [16,19,36,43].

    • Cultural determinants of food attitudes in anosmic patients

      2020, Appetite
      Citation Excerpt :

      Similarly, more recent studies have stated even higher percentages of patients who have declared a modification to their eating habits since olfactory impairment. To date, dysosmic patients (which includes partial smell loss) have been shown to use more spices/condiments (Ferris & Duffy, 1989; Manesse et al., 2017; Mattes et al., 1990) and salt (Henkin, 2014), seek texture/chemesthesis (Croy et al., 2014; Ferris & Duffy, 1989; Merkonidis et al., 2015; Postma, De Graaf, & Boesveldt, 2019), and appearance (Ferris & Duffy, 1989; Merkonidis et al., 2015). However, many of these reports observed relatively few direct effects of dysosmia on food preferences or dietary intake compared to controls – this seems especially true for long-term anosmic patients (Doty, 1977; Ferris & Duffy, 1989; Mattes et al., 1990; Mattes & Cowart, 1994; Seo & Hummel 2009).

    • Associations of olfactory dysfunction with anthropometric and cardiometabolic measures: Findings from the 2013–2014 national health and nutrition examination survey (NHANES)

      2020, Physiology and Behavior
      Citation Excerpt :

      Individuals with olfactory dysfunction may make changes to their eating habits by implementing strategies to compensate for sensory changes [6]. Salt usage and/or intake of salty foods have been reported to be higher in persons with hyposmia when compared with those with normal olfactory function [7]. Other reports suggest olfactory dysfunction is associated with certain dietary patterns, such as lower preference for sour or bitter fruits and vegetables, lower micronutrient intake (folate, magnesium, and phosphorous), and higher intake of sweets [8-10].

    • The Effects of Short Sleep Duration and Deprivation on Gustation and Olfaction: Implications for Dietary Intake

      2020, Neurological Modulation of Sleep: Mechanisms and Function of Sleep Health
    • Effects of nutritional status and cognitive ability on olfactory function in geriatric patients

      2016, Auris Nasus Larynx
      Citation Excerpt :

      Nonetheless, the parameters that we used did not show any significant correlation with olfactory function test results except threshold score and BMI (Table 4). The threshold score of the KVSS II test showed significant negative correlation with BMI, and this result could be explained by the fact that older patients with decreasing olfactory function have compensatory strategies that may have already developed such as preference for foods with enhanced primary taste qualities (e.g., salty or sugary) [12,24]. These compensatory strategies could result in increased food intake and weight gain in the patients with olfactory dysfunction.

    View all citing articles on Scopus
    View full text