Repeated Exposure to Low-Sodium Cereal Affects Acceptance but Does not Shift Taste Preferences or Detection Thresholds of Children in a Randomized Clinical Trial

Nuala Bobowski; Julie A Mennella

doi:10.1093/jn/nxz014

. 2019 Apr 22;149(5):870–876. doi: 10.1093/jn/nxz014

Repeated Exposure to Low-Sodium Cereal Affects Acceptance but Does not Shift Taste Preferences or Detection Thresholds of Children in a Randomized Clinical Trial

Nuala Bobowski ^1,^2,^✉, Julie A Mennella ¹

PMCID: PMC6862934 PMID: 31006818

ABSTRACT

Background

Although salt taste preference is malleable in adults, no research to date has focused on children, whose dietary sodium intake exceeds recommended intake and whose salt taste preferences are elevated.

Objective

This proof-of-principle trial determined whether 8-wk exposure to low-sodium cereal (LSC) increased children's acceptance of its taste and changed their salty and sweet taste preferences.

Methods

Children (n = 39; ages 6–14 y; 67% female) were randomly assigned to ingest LSC or regular-sodium cereal (RSC) 4 times/wk for 8 wk. The cereals, similar in sugar (3 g/cup compared with 2 g/cup) and energy content (100 kcal/cup) yet different in sodium content (200 mg sodium/cup compared with 64 mg sodium/cup), were chosen based on taste evaluation by a panel of children. Mothers completed daily logs on children's cereal intake. At baseline and after the exposure period, taste tests determined which cereal children preferred and measured children's most preferred amount of salt (primary outcomes), and most preferred amount of sucrose and salt taste detection thresholds (secondary outcomes). Repeated measures ANOVAs were conducted on primary and secondary outcomes, and generalized estimating equations were conducted on amount of cereal ingested at home over time.

Results

Both treatment groups accepted and ate the assigned cereal throughout the 8-wk exposure. There were no group × time interactions in salt detection thresholds (P = 0.32) or amount of salt (P = 0.30) and sucrose (P = 0.77) most preferred, which were positively correlated (P = 0.001). At baseline and after the exposure, the majority in both groups preferred the taste of the RSC relative to LSC (P > 0.40).

Conclusions

Children showed no change in salt preference but readily ate the LSC for 8 consecutive weeks. Findings highlight the potential for reducing children's dietary salt intake by incorporating low-sodium foods in the home environment without more preferred higher-salt versions of these foods. This trial was registered at clinicaltrials.gov as NCT02909764.

Keywords: children, salt, sodium, taste detection threshold, taste preference, repeated exposure, cereal, ingestive behavior

Introduction

Like their parents, American children consume sodium at amounts far exceeding recommendations of the Dietary Guidelines for Americans (<2300 mg/d) (1). Not accounting for salt added at the table, 6–18-y-old American children consume on average about 3300 mg sodium/d (2). Not only is sodium an essential mineral, but it renders a preferred taste and plays important functional roles in cooking and food processing, including blocking bitter tastes, controlling fermentation, adding texture, and preserving food (3–6). Consequently, manufactured foods are the largest contributors to sodium in the diet of children and adults (2, 7).

Once considered a disease of adulthood, hypertension—in part a consequence of high sodium intake—has increased in prevalence among the pediatric population (8). Because high blood pressure tracks from childhood into adulthood (9), interventions to reduce salt intake among children remain a public health priority (4). However, reducing dietary salt presents a considerable challenge among people of all ages because of the strong appeal of salty taste, and among children in particular because preference for salty taste, similar to that for sweet taste, is elevated during periods of growth (10, 11).

Two lines of research suggest that salt taste preference is a malleable trait. Conducted >35 y ago, 1 line of research focused on the effects of lowering intake of sodium in the overall diet by 30–50% for 5 mo (12) to 1 y (13, 14). Although the immediate response was to dislike the taste of low-sodium foods (15), these intervention trials showed that adults acclimated over time. After the diet intervention, participants perceived foods that contained higher amounts of salt as tasting too salty and gave higher pleasantness ratings for the taste of low-sodium soup, low-sodium crackers, or both when compared to ratings given before the intervention (12–14).

The second line of research focused on the sensory effects of repeated ingestion of lower amounts of salt (79–100%) in a single food [e.g., soup (16)] or beverage [e.g., tomato juice (17, 18) over 2 wk (16) or 16 wk (17)], and within the context of a diet otherwise unchanged. Repeated ingestion of the lower-sodium food increased liking for its taste (16), and repeated ingestion of the lower-sodium beverage increased the number of subjects who gave higher liking ratings to the low-sodium version after the exposure period (17). Repeated exposure to a lower-sodium (less salty) food may acclimate the individual to a new appropriate amount of saltiness for that particular food (16).

Despite the current higher-than-recommended salt intakes among children and evidence that children, as a group, most prefer greater salty and sweet tastes than do adults (11), no research to date has focused on the effects of lowering salt intake among pediatric populations. To this end, we conducted a proof-of-principle study to determine whether repeated exposure to a low-sodium food for 8 wk would increase children's relative preference for that food and reduce the salt taste most preferred. Breakfast cereals were selected as the test food because grain products are regularly consumed by children (19) and are significant contributors to children's overall sodium intake (2), and because there is wide variation in sodium content among different cereal brands (20). Because repeated exposure is an effective strategy to increase children's liking of initially novel and/or disliked foods and flavors (21–24), we hypothesized that increasing children's familiarity with the taste of a low-sodium cereal (LSC) would result in 1) increased acceptance of its taste and intake over time,2) shifts in relative preference for the LSC over the regular-sodium cereal (RSC), and 3) shifts in the most preferred saltiness in a different food, broth (primary outcomes). Secondary outcomes included salt taste detection thresholds [i.e., the lowest concentration of a taste detected by an individual relative to water (25)], which are unrelated to taste hedonics (26). If there was an intervention-induced shift in amount of salt most preferred, detection threshold data would allow us to determine whether it was independent of changes in the taste sensitivity to salt (12–14, 27). Given the concordance of most preferred amount of salty and sweet tastes among children (11), and because breakfast cereals geared for children are typically sweetened (28), we also phenotyped the children for their most preferred amount of sweetness as another secondary outcome.

Methods

Participants

Mothers were recruited from a list of past participants who asked to be contacted for future studies. Dyads were eligible if the child regularly consumed cereal, did not have any food allergies, was not taking any medications known to affect taste, and if the child's mother agreed not to purchase any cereals during the 8-wk period in which the child would be participating in the study. Demographic and household data were collected by maternal interview, and children were weighed (kg; model 439 physical scale, Detecto Scale Company) and measured for height (cm) wearing light clothing and no shoes, to calculate age- and sex-specific BMI z scores (EpiInfo 3.5). The Office of Regulatory Affairs at the University of Pennsylvania approved all procedures, and written informed consent from each mother and assent from each child who was aged ≥7 y were obtained before the start of the study. The trial was registered at clinicaltrials.gov as NCT02909764.

Sensory panel pilot study: choice of food stimuli

To determine which pairs of cereals to use in the trial, we conducted a pilot study on children (30 girls, 17 boys) who were between the ages of 6 and 14 (mean ± SEM: 10 ± 0.3) y. As shown in Supplemental Table 1, we identified 5 different pairs of cereals. Although the pairs of cereals were similar in flavor, size, shape, and caloric content, 1 cereal in the pair had significantly lower sodium content, which ranged from a 37% to 67% difference on a weight-by-weight basis. Serving sizes, indicated by the manufacturer for each cereal, ranged from 28 to 59 g. One cereal within each pair met the FDA requirements for a “low-sodium” nutrient content claim [≤140 mg sodium/serving, assuming a reference amount customarily consumed of >30 g, an amount determined by the FDA and used by manufacturers to establish serving size) (29)], and is hereafter referred to as the LSC. The other cereal within the pair had a sodium content of 160–210 mg sodium/serving, which is on par with cereals typically marketed to children (30), and is hereafter referred to as the RSC. During the taste test, children were individually presented with pairs of cereals (5 g each), in randomized and counterbalanced order and, after tasting each, were asked to point to the cereal they liked better, rinsing their mouth with water before and after each tasting. Children were then asked whether they would be willing to eat each cereal for 8 wk. The percentage of children who preferred the RSC or LSC within each pair was determined and a binominal test was used to determine relative preference. Chi-square analyses were used to compare the proportion of children who were willing to consume the RSC rather than the LSC within each pair.

As shown in Supplemental Table 1, children preferred the taste of the RSC over the LSC for 4 of the 5 pairs of cereals (all P ≤ 0.02); for the remaining pair, children were no more likely to prefer the RSC than they were the LSC (P = 0.77). When asked whether they would be willing to ingest the individual cereals, there was no difference in children's willingness to eat the LSC or RSC within 4 of the 5 pairs (all P ≥ 0.11); however, most children indicated that they were not willing to eat low-sodium Barbara's Brown Rice Crisps (P < 0.01). We selected corn flakes as the food stimuli for the trial for 2 reasons. First, children were as willing to eat low-sodium Barbara's corn flakes (57%) as they were regular-sodium Kellogg's corn flakes (62%; P = 0.67). Second, the difference in sodium content between these 2 cereals (67%) was considerably higher than the just-noticeable difference for salt (∼12%) (31), although the manufacturer serving size differed between cereals [serving size was 1.5 cups (40 g) for the LSC and 1 cup (28 g) for the RSC]. Because children were proffered 1-cup scoops (237 mL by volume) of the cereals during the at-home exposure period, which were equivalent to 27 g LSC and 28 g RSC, we compared the salt, sugar, and caloric content per cup of cereal. As shown in Supplemental Table 1, per cup, the cereals were similar in sugar and caloric content (LSC: 2 g sugar, 100 kcal compared with RSC: 3 g sugar, 100 kcal), but differed in sodium content (64 compared with 200 mg).

Proof-of-principle intervention trial overview

We conducted an 8-wk trial in which children were randomly assigned to eat either low-sodium corn flakes (64 mg sodium, 100 kcal per 27 g/1 cup; LSC) or regular-sodium corn flakes (200 mg sodium, 100 kcal per 28 g/1 cup; RSC). The number of children randomly assigned to each cereal treatment group (LSC group, n = 20; RSC group, n = 19) was determined based on published data of an increase in adults’ liking for a no-salt-added soup following repeated exposure to the soup (16), with a sample size of 19 powered at 84% and 5% significance. At the baseline and 4-wk (midway) study visits, mothers were given a 4-wk supply of the assigned cereal for their child, along with a 1-cup scoop to measure the amount of cereal to offer their child each day, and data sheets to record what the child ate. Completed data sheets were returned by mothers after week 4 and then again after week 8. All cereal was removed from packaging to ensure mothers and children were blind to cereal brand and nutrition information, and mothers were provided with enough cereal to account for children requesting more cereal than the 1-cup scoop. A period of 8 wk was selected because this was the length of time after which adults began to rate the taste of a low-sodium broth and low-sodium crackers as more pleasant while following a low-sodium diet (12).

Mothers were instructed to first offer their child 1 cup, eaten either plain or with milk only, at least 4 times/wk on 4 separate days during the 8-wk trial, and were told that their child was allowed to consume as much or as little as the child wished. If children requested more cereal, mothers provided additional scoop(s) of cereal. If children were not interested in eating the cereal, mothers were asked to prompt their child to “take a taste,” because research in children has shown repeated tastings of a food increases liking and acceptance over time (21–24). On the provided food logs, mothers recorded the time of day their child ate the cereal; the amount ingested, and whether it was eaten alone or with milk. From these records, we determined the amount of cereal (in g) that the child ingested each day of the exposure period. To encourage compliance, mothers received reminder calls twice weekly. After the trial, mothers were contacted and asked whether they encountered any problems getting the children to taste/eat the cereal during the at-home exposure period.

Testing procedures were identical for all children, each of whom was tested privately in a room specifically designed for sensory testing. Mothers were instructed that their children should not consume any food or drink other than water for at least 1 h before taste testing at Monell. The primary outcome measures were the salty taste most preferred and liking of the LSC over time. Children were also phenotyped for salty taste detection thresholds and the sweet taste most preferred (secondary outcomes; see below). The taste stimuli for the sweet preference test and salty taste detection thresholds were prepared in solution with deionized water, and stimuli for salt preference tests were prepared by adding varying amounts of salt to low-sodium vegetable broth (Campbell Soup Co). All solutions were refrigerated at 4°C in amber glass bottles and prepared every week, or more frequently as needed. Water solutions were equilibrated to room temperature 2 h before testing, and broth was heated in a water bath set at 40°C. The psychophysical procedures used to measure preferences and detection threshold follow.

Amount of salt and sucrose most preferred

Children's most preferred amounts of salt and sucrose were determined separately using a 2-series, paired-comparison, forced-choice tracking procedure [see reference for more details (32)]. In brief, participants were presented with pairs of broths (5 mL each) with varying concentrations of added salt (0.16, 0.24, 0.38, 0.61, 1.05 M) (17) or pairs of sucrose solutions (5 mL each) of varying concentrations (0.09, 0.18, 0.35, 0.70, 1.05 M). The first pair of broths (0.24 and 0.61 M salt) or sucrose solutions (0.18 and 0.70 M sucrose) presented were from the middle range of concentrations. Children were instructed to taste each sample within a pair for 5 s, to rinse between tastings, and then to point to the sample they liked better. A 1-min period during which children rinsed their mouth with water separated each pair of samples. Each subsequent pair of samples presented contained the concentration selected by the participant paired with an adjacent stimulus concentration. This pattern continued until the participant either chose the same concentration when paired with both a lower and higher concentration in 2 consecutive pairs or chose either the highest or the lowest concentration twice consecutively.

The entire task was repeated after a 3-min break, with stimulus pairs presented in reverse order (i.e., weaker stimulus presented first in the first series; stronger stimulus first in the second series). This method controls for position bias and enables researchers to determine objectively whether the child understands the task or is responding by pointing to whatever is presented to the right or left; if responding at random, the most preferred concentration in series 1 would be ≥3 steps apart from the most preferred concentration in series 2. The geometric mean of the 2 concentrations chosen in the first and second series was calculated to determine the most preferred amounts of salt and sucrose.

Salt taste detection thresholds

Detection thresholds were measured via a 2-alternative forced-choice procedure developed at the Monell Center and adapted for use for pediatric populations [see reference (33) for details]. Salt solutions (N = 18) ranged in concentration from 0.56 × 10⁻⁴ to 1.0 M NaCl and were made through a quarter-log serial dilution of the 1.0 M NaCl solution. Before testing, children were trained to become familiar with the method and to assess whether they understood the detection threshold task.

During testing, children were presented with pairs of solutions, 1 of which was distilled water and the other the salt solution. Children tasted each sample within a pair for 5 s, rinsed between tastings, and then pointed to the sample that had a taste, as was done in the training task. The first pair offered included water and a 1.0 × 10⁻³ M NaCl solution. The concentration of the solution presented in the subsequent pair was increased after a single incorrect response (i.e., participant pointed to water) and decreased after 2 consecutive correct responses (i.e., participant pointed to the solution containing salt). A reversal occurred when the concentration sequence changed direction (i.e., incorrect response followed by 2 correct responses or vice versa). The mean of the log values of the last 4 reversals was the measured salt detection threshold. Measuring detection thresholds in children using this method takes <15 min.

Forced-choice cereal taste test

In randomized and counterbalanced order, children were presented with 5 g each of the LSC and RSC. After tasting and ingesting each cereal in counterbalanced order and rinsing their mouth with water twice between tastings, they were instructed to point to the cereal they liked better.

Statistical analyses

Data were analyzed using SPSS (version 24; SPSS Inc.), and Stata version 12 (StataCorp LP). Depending on the data, independent t tests or chi-square analyses were used to determine whether there were differences in baseline characteristics and the completion of each of the psychophysical tasks between the 2 treatment groups (LSC compared with RSC).

Repeated-measures ANOVAs were conducted on the most preferred amount of salt (primary outcome), most preferred amount of sucrose, and salt detection thresholds (secondary outcomes), and included cereal treatment group (LSC, RSC) as the between-subjects factor and time as the within-subject factor. Generalized estimating equations were conducted on the amount of cereal ingested during the home-exposure period. The generalized estimating equations approach accounts for the repeated measurements of outcomes over time for each child and examines whether the slopes of the lines created differ between the treatment groups. Yates's χ² analyses were used to determine which of the 2 cereals children in each group preferred at baseline and after the 8-wk exposure period, and whether the number of children who shifted preference from the RSC at baseline to the LSC after the exposure period differed between groups. Finally, Pearson correlation coefficients were conducted to determine associations among psychophysical measures (i.e., most preferred amount of salt, most preferred amount of sucrose, salty taste detection thresholds); mean values for each outcome (i.e., most preferred amount of salt, most preferred amount of sucrose, salt detection thresholds) were used in the correlational analyses unless the child completed the task on only 1 study visit (Supplemental Table 2). All summary statistics are presented as means ± SEM or percentage of the group; statistical significance level was set at P < 0.05 (2-tailed).

Results

Participant characteristics and task performance

As illustrated in Figure 1, we enrolled and randomized 39 children, and 100% completed the 8-wk trial. The groups did not differ in age, sex ratio, demographics, or anthropometric measures at baseline (all P ≥ 0.14; Table 1). The vast majority completed and understood the psychophysical tasks that determined their most preferred salty and sweet tastes, preferred cereal, and salt detection thresholds (Supplemental Table 2). There were no differences between the cereal treatment groups in their comprehension and completion of each of these tasks (all P ≥ 0.63).

Trial profile. LSC, low-sodium cereal; RSC, regular-sodium cereal.

TABLE 1.

Participant characteristics at baseline¹

		Cereal treatment group
Characteristic	All children	LSC (n = 20)	RSC (n = 19)	P value²
Age, y	11.3 ± 0.4	11.3 ± 0.5	11.4 ± 0.5	0.86
Race, % (n)				0.58
Black	69.2 (27)	80.0 (16)	57.9 (11)
White	12.8 (5)	10.0 (2)	15.8 (3)
Other	17.9 (7)	10.0 (2)	26.3 (5)
Hispanic ethnicity, % (n)	25.6 (10)	25.0 (5)	26.3 (5)	0.93
Female, % (n)	66.7 (26)	65.0 (13)	68.4 (13)	0.82
BMI z score	0.23 ± 0.2	0.45 ± 0.3	−0.004 ± 0.3	0.30
Socioeconomic characteristics of family
Family income, % (n)³				0.14
<$15,000	30.8 (12)	35.0 (7)	26.3 (5)
$15,000–34,999	23.1 (9)	5.0 (1)	42.1 (8)
$35,000–74,999	35.9 (14)	40.0 (8)	31.6 (6)
≥$75,000	7.7 (3)	15.0 (3)	0 (0)
Mother's highest grade of education, % (n)³				0.26
High school	33.3 (13)	35.0 (7)	31.6 (6)
Trade school	15.4 (6)	10.0 (2)	21.1 (4)
College	35.9 (14)	25.0 (5)	47.4 (9)
Graduate school	12.8 (5)	25.0 (5)	0 (0)

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¹Values are means ± SEMs or percentages (frequencies). LSC and RSC means differ, P < 0.05. LSC, low-sodium cereal; RSC, regular-sodium cereal.

² P values for main effect of treatment group, obtained from Yates's χ² test or independent t tests with group as the between-subject factor.

³Some values do not sum to total because of missing data.

Cereal taste tests and home exposure acceptance of cereal

At baseline, the majority of children in both cereal treatment groups [LSC: 75% (15 of 20); RSC: 84% (16 of 19)] preferred the taste of the RSC over the LSC [Yates's χ² (2) = 0.10, P = 0.75]. During the 8-wk home exposure period, each mother reported that she removed all other cereals from the home environment, that her child tasted and ate the cereal without difficulty, and that they complied with study protocol. From the daily logs, we found that children ingested, on average, 21 g of cereal on each exposure day, ranging from a taste to several cups of cereal. As shown in Figure 2, there was no significant group × time interaction for the amount of cereal ingested during the home exposure period (P = 0.88), but there was a tendency for a group effect (P = 0.07). Although the LSC group accepted and ate the LSC each consecutive day for 8 wk, they tended to ingest less cereal overall than the RSC group (16.7 ± 3.7 compared with 25.6 ± 3.3 g).

Cereal intake (g) during the home exposure period by cereal treatment group (LSC, RSC). Values are means ± SEM; n = 20 LSC and n = 19 RSC. LSC, low-sodium cereal; RSC, regular-sodium cereal.

Although children ate the cereal as instructed during the home-exposure period, the intervention had no impact on cereal preference post intervention. When given a choice between the LSC and RSC, the majority of children in both groups continued to prefer the RSC at the end of the intervention (LSC group: 80%, RSC group: 63%; Yates's χ² (1) = 0.66, P = 0.41). In addition, of the 31 children who preferred the RSC at baseline, only 8 shifted their relative preference to the LSC after the home-exposure period: 13% (2 of 15) of the LSC group and 38% (6 of 16) of the RSC group [Yates's χ² (1) = 1.62, P = 0.20].

Taste preferences and detection threshold

Focusing on children who completed both baseline and postexposure psychophysical testing (see Supplemental Table 2), we found no significant group, time, or group × time effects for the salty (P = 0.30; Figure 3A) and sweet (P = 0.77) tastes most preferred (Figure 3B), and there were no group differences over time in salty taste detection thresholds (P = 0.32; Figure 3C). The relation between the child's most preferred amount and detection threshold for salt was not significant at baseline [r(30df) = 0.29; P = 0.10] nor after the 8-wk exposure period [r(29df) = 0.21; P = 0.27]; however, the amount of salt most preferred was significantly correlated with the amount of sucrose most preferred both at baseline [r(32df) = 0.40, P = 0.04] and after the exposure period [r(34df) = 0.37, P = 0.03]. Regardless of cereal treatment group, the higher the child's average most preferred amount of salt, the higher the most preferred amount of sucrose [r(37df) = 0.51; P = 0.001; Figure 4].

The amount of salt (M) most preferred (A; n = 16 LSC and 16 RSC), amount of sucrose (M) most preferred (B; n = 20 LSC and 19 RSC), and detection thresholds (M) for salt (C; n = 15 LSC and 16 RSC) at baseline and after 8-wk exposure period by cereal treatment group (LSC, RSC). Values are means ± SEM. LSC, low-sodium cereal; RSC, regular-sodium cereal.

The relation between each child's most preferred salty taste and most preferred sweet taste. Values are means of 2 test sessions, n = 16 LSC and 15 RSC; or 1 test session, n = 4 LSC and 4 RSC. LSC, low-sodium cereal; RSC, regular-sodium cereal.

Discussion

The current proof-of-principle trial explored whether repeated exposure, a strategy shown to be effective both for shifting adults’ liking for salt in a food (16, 17) and for enhancing the acceptance of novel foods among children (21–24), would enhance the acceptance of a LSC over time. Children and their mothers complied with study protocol with excellent retention rates. Those children randomly assigned the LSC ate and therefore accepted the cereal throughout the 8-wk home exposure, a finding consistent with prior research on children's acceptance of cereals lower in sugar (34). Taken together, these findings illustrate children's willingness to ingest healthier cereals when offered no other option (34). However, when given a choice, most children preferred the RSC over the LSC even after repeated exposure to the latter, and their most preferred salty taste remained unchanged.

Childhood is a time when preference for the taste of salt (and sweet) is heightened (11), driven in part by a need for sodium (and calories) during periods of growth (10, 11). Based on this taste biology, we present several hypotheses, not mutually exclusive, to account for the present findings.

First, the length of the trial may not have been sufficient to shift children's salt taste preference either in cereal or in another food (broth). We exposed children to the cereal for 8 wk based on the length of time required for adults to prefer lower concentrations of salt in broth and crackers after eating a low-sodium diet (12). However, children prefer higher amounts of salt than adults (11, 35), so they may require longer periods of time before changes become evident.

Second, the strategy of repeated exposure to a single low-sodium food within the context of a diet otherwise unchanged may not be effective for children. In the present study, we repeatedly exposed children to a LSC without otherwise manipulating the sodium content of their diet. Changing children's salt preferences may require an overall low-sodium diet, similar to the strategy used in adults by Bertino and colleagues (12), which would, in turn, repeatedly expose children to a variety of low-sodium foods simultaneously.

Third, the type of food chosen for the home-exposure period may have contributed to the lack of change in relative preference for the LSC. Although grain products such as cereal are major contributors to children's overall dietary salt intake (2), salt is typically “hidden”—added for its functional properties [e.g., to improve flavor, texture (3–6)] and not necessarily to increase salty taste. As such, children's relative lower intake of the LSC may not have been based on less saltiness per se, but instead on changes to overall sensory profile as a result of its reduced salt, including increased perception of unpleasant tastes (e.g., bitterness) and off-flavors (6, 36, 37). Whether repeated exposure to a low-sodium version of a characteristically “salty” food such as soup would yield different findings is an important area for future research. In the adult intervention studies, repeated exposure to a low-sodium soup (16) or low-sodium tomato juice (17, 18) resulted in increased liking for those foods. In those studies, liking ratings of individual foods were made on Likert scales, which allowed determination of any changes in how much each food was liked over time. In the present study, we used a forced-choice procedure such that children had to pick which cereal tasted better. Although the children in the LSC group accepted and ate the LSC, when they were given the choice, the vast majority preferred the taste of the RSC both before and after the intervention. Future investigations should include measurements of liking using age-appropriate scales [e.g., facial hedonic scales (38)].

Fourth, the concordance in children's most preferred salty and sweet tastes, a finding consistent with prior research (11), suggests that reducing dietary salt alone may not be effective for children. Although the test cereals were matched for and relatively low in sugar content, we hypothesize that a more effective approach may require reductions in both saltiness and sweetness (e.g., added sugars, low-calorie sweeteners) in the overall diet, given the association between children's sweet and salty taste preferences as demonstrated herein. However, identifying foods and beverages to include in such strategies will likely present a considerable challenge given that the current food environment is rich in manufactured foods and beverages high in both added sweeteners and salt.

In Strategies to reduce sodium intake in the United States (4), the Institute of Medicine outlined a series of recommendations to reduce dietary salt intake of Americans, which largely focused on the malleability of adults’ salty taste preferences, including gradual stepwise reduction of salt in processed foods, which would in turn allow the population to adapt to the taste of a less salty diet without impacting acceptance of lower-sodium foods. In making such recommendations, the Institute of Medicine made special note regarding pediatric populations: “It is likely that during infancy and childhood, the salt environment—and any changes in it that result from lowering the overall salt level in the food environment—will have the most profound effects” (4).

In the present study, although children in the LSC group did not shift their relative preference to the LSC, they were no less likely than those in the RSC group to comply with the study protocol. In other words, children were willing to ingest the LSC when it was the only option available, a finding that highlights the importance of creating an environment for children in which low-sodium foods are accessible, and 1 that largely supports national efforts to reduce salt in processed foods. This proof-of-principle study holds promise that such research can be conducted in children. Research to determine what strategies are most effective to accomplish this goal remains a public health priority.

Supplementary Material

nxz014_supplemental_files

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Acknowledgments

We acknowledge the expert technical assistance of Naomi Pressman, Ashley Reiter, Loma Inamdar, and Loran Daniels, and insightful comments of Dr. Jennifer Orlet Fisher on an earlier version of the manuscript. The authors’ responsibilities were as follows—NB and JAM: designed the research, analyzed data, and wrote the manuscript; NB: conducted research; and all authors: read and approved the final paper.

Notes

Supported by National Research Service Award F32 DC15172 and R01 grants (R01DC01128, R01DC016616) from the National Institute of Deafness and Other Communication Disorders. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funding agencies had no role in the design and conduct of the study; in the collection, analysis, or interpretation of the data; or in the preparation, review, or approval of the manuscript.

Author disclosures: NB, JAM, no conflicts of interest.

Supplemental Tables 1 and 2 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/jn.

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8. Leyvraz M, Chatelan A, da Costa BR, Taffé P, Paradis G, Bovet P, Bochud M, Chiolero A. Sodium intake and blood pressure in children and adolescents: a systematic review and meta-analysis of experimental and observational studies. Int J Epidemiol. 2018;47(6):1796–810. [DOI] [PubMed] [Google Scholar]
9. Chen X, Wang Y. Tracking of blood pressure from childhood to adulthood: a systematic review and meta-regression analysis. Circulation. 2008;117(25):3171–80. [DOI] [PMC free article] [PubMed] [Google Scholar]
10. Coldwell SE, Oswald TK, Reed DR. A marker of growth differs between adolescents with high vs. low sugar preference. Physiol Behav. 2009;96(4–5):574–80. [DOI] [PMC free article] [PubMed] [Google Scholar]
11. Mennella JA, Finkbeiner S, Lipchock SV, Hwang L, Reed DR. Preferences for salty and sweet tastes are elevated and related to each other during childhood. PLoS One. 2014;9(3):e92201. [DOI] [PMC free article] [PubMed] [Google Scholar]
12. Bertino M, Beauchamp GK, Engelman K. Long-term reduction in dietary sodium alters the taste of salt. Am J Clin Nutr. 1982;36(6):1134–44. [DOI] [PubMed] [Google Scholar]
13. Elmer PJ. The effect of dietary sodium reduction and potassium-chloride supplementation on sodium-chloride taste perceptions in mild hypertensives [dissertation]. Minneapolis (MN): University of Minnesota; 1989. [Google Scholar]
14. Blais CA, Pangborn RM, Borhani NO, Ferrell MF, Prineas RJ, Laing B. Effect of dietary sodium restriction on taste responses to sodium chloride: a longitudinal study. Am J Clin Nutr. 1986;44(2):232–43. [DOI] [PubMed] [Google Scholar]
15. Bertino M, Beauchamp GK, Riskey DR, Engelman K. Taste perception in three individuals on a low sodium diet. Appetite. 1981;2(1):67–73. [DOI] [PubMed] [Google Scholar]
16. Methven L, Langreney E, Prescott J. Changes in liking for a no added salt soup as a function of exposure. Food Qual Prefer. 2012;26(2):135–40. [Google Scholar]
17. Bobowski N, Rendahl A, Vickers Z. A longitudinal comparison of two salt reduction strategies: acceptability of a low sodium food depends on the consumer. Food Qual Prefer. 2015;40(Part B):270–8. [Google Scholar]
18. Bobowski N, Rendahl A, Vickers Z. Preference for salt in a food may be alterable without a low sodium diet. Food Qual Prefer. 2015;39:40–5. [Google Scholar]
19. Albertson AM, Thompson DR, Franko DL, Holschuh NM. Weight indicators and nutrient intake in children and adolescents do not vary by sugar content in ready-to-eat cereal: results from National Health and Nutrition Examination Survey 2001–2006. Nutr Res. 2011;31(3):229–36. [DOI] [PubMed] [Google Scholar]
20. Gillespie C, Maalouf J, Yuan K, Cogswell ME, Gunn JP, Levings J, Moshfegh A, Ahuja JKC, Merritt R. Sodium content in major brands of US packaged foods, 2009. Am J Clin Nutr. 2014;101(2):344–53. [DOI] [PMC free article] [PubMed] [Google Scholar]
21. Birch LL. Development of food preferences. Annu Rev Nutr. 1999;19(1):41–62. [DOI] [PubMed] [Google Scholar]
22. Anzman-Frasca S, Savage JS, Marini ME, Fisher JO, Birch LL. Repeated exposure and associative conditioning promote preschool children's liking of vegetables. Appetite. 2012;58(2):543–53. [DOI] [PubMed] [Google Scholar]
23. Mennella JA, Reiter AR, Daniels LM. Vegetable and fruit acceptance during infancy: impact of ontogeny, genetics, and early experiences. Adv Nutr. 2016;7(1):219S. [DOI] [PMC free article] [PubMed] [Google Scholar]
24. Sullivan SA, Birch LL. Pass the sugar, pass the salt: experience dictates preference. Dev Psychol. 1990;26(4):546. [Google Scholar]
25. Mattes RD. Salt taste and hypertension: a critical review of the literature. J Chronic Dis. 1984;37(3):195–208. [DOI] [PubMed] [Google Scholar]
26. Jayasinghe SN, Kruger R, Walsh DC, Cao G, Rivers S, Richter M, Breier BH. Is sweet taste perception associated with sweet food liking and intake?. Nutrients. 2017;9(7):750. [DOI] [PMC free article] [PubMed] [Google Scholar]
27. Bertino M, Beauchamp GK, Engelman K. Increasing dietary salt alters salt taste preference. Physiol Behav. 1986;38(2):203–13. [DOI] [PubMed] [Google Scholar]
28. Walker RW, Goran MI. Laboratory determined sugar content and composition of commercial infant formulas, baby foods and common grocery items targeted to children. Nutrients. 2015;7(7):5850–67. [DOI] [PMC free article] [PubMed] [Google Scholar]
29. Food and Drug Administration. Code of Federal Regulations Title 21, nutrient content claims for the sodium content of food. [Internet]. [cited 27 August 2018]. Washington (DC)2017. Available from: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.61. [Google Scholar]
30. Schwartz MB, Vartanian LR, Wharton CM, Brownell KD. Examining the nutritional quality of breakfast cereals marketed to children. J Am Diet Assoc. 2008;108(4):702–5. [DOI] [PubMed] [Google Scholar]
31. Bobowski N, Vickers Z. Determining sequential difference thresholds for sodium chloride reduction. J Sens Stud. 2012;27(3):168–75. [Google Scholar]
32. Mennella JA, Lukasewycz LD, Griffith JW, Beauchamp GK. Evaluation of the Monell forced-choice, paired-comparison tracking procedure for determining sweet taste preferences across the lifespan. Chem Senses. 2011;36(4):345–55. [DOI] [PMC free article] [PubMed] [Google Scholar]
33. Bobowski NK, Mennella JA. Disruption in the relationship between blood pressure and salty taste thresholds among overweight and obese children. J Acad Nutr Diet. 2015;115(8):1272–82. [DOI] [PMC free article] [PubMed] [Google Scholar]
34. Harris JL, Schwartz MB, Ustjanauskas A, Ohri-Vachaspati P, Brownell KD. Effects of serving high-sugar cereals on children's breakfast-eating behavior. Pediatrics. 2011;127(1):71–6. [DOI] [PubMed] [Google Scholar]
35. Beauchamp GK, Cowart BJ. Preference for high salt concentrations among children. Dev Psychol. 1990;26(4):539. [Google Scholar]
36. Liem DG. Infants’ and children's salt taste perception and liking: a review. Nutrients. 2017;9(9):1011. [DOI] [PMC free article] [PubMed] [Google Scholar]
37. Gillette M. Flavor effects of sodium chloride. Food Technol. 1985;39(6):47–50. [Google Scholar]
38. Chen AW, Resurreccion A, Paguio LP. Age appropriate hedonic scales to measure food preferences of young children. J Sens Stud. 1996;11(2):141–63. [Google Scholar]

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[bib12] 12. Bertino M, Beauchamp GK, Engelman K. Long-term reduction in dietary sodium alters the taste of salt. Am J Clin Nutr. 1982;36(6):1134–44. [DOI] [PubMed] [Google Scholar]

[bib13] 13. Elmer PJ. The effect of dietary sodium reduction and potassium-chloride supplementation on sodium-chloride taste perceptions in mild hypertensives [dissertation]. Minneapolis (MN): University of Minnesota; 1989. [Google Scholar]

[bib14] 14. Blais CA, Pangborn RM, Borhani NO, Ferrell MF, Prineas RJ, Laing B. Effect of dietary sodium restriction on taste responses to sodium chloride: a longitudinal study. Am J Clin Nutr. 1986;44(2):232–43. [DOI] [PubMed] [Google Scholar]

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[bib17] 17. Bobowski N, Rendahl A, Vickers Z. A longitudinal comparison of two salt reduction strategies: acceptability of a low sodium food depends on the consumer. Food Qual Prefer. 2015;40(Part B):270–8. [Google Scholar]

[bib18] 18. Bobowski N, Rendahl A, Vickers Z. Preference for salt in a food may be alterable without a low sodium diet. Food Qual Prefer. 2015;39:40–5. [Google Scholar]

[bib19] 19. Albertson AM, Thompson DR, Franko DL, Holschuh NM. Weight indicators and nutrient intake in children and adolescents do not vary by sugar content in ready-to-eat cereal: results from National Health and Nutrition Examination Survey 2001–2006. Nutr Res. 2011;31(3):229–36. [DOI] [PubMed] [Google Scholar]

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[bib21] 21. Birch LL. Development of food preferences. Annu Rev Nutr. 1999;19(1):41–62. [DOI] [PubMed] [Google Scholar]

[bib22] 22. Anzman-Frasca S, Savage JS, Marini ME, Fisher JO, Birch LL. Repeated exposure and associative conditioning promote preschool children's liking of vegetables. Appetite. 2012;58(2):543–53. [DOI] [PubMed] [Google Scholar]

[bib23] 23. Mennella JA, Reiter AR, Daniels LM. Vegetable and fruit acceptance during infancy: impact of ontogeny, genetics, and early experiences. Adv Nutr. 2016;7(1):219S. [DOI] [PMC free article] [PubMed] [Google Scholar]

[bib24] 24. Sullivan SA, Birch LL. Pass the sugar, pass the salt: experience dictates preference. Dev Psychol. 1990;26(4):546. [Google Scholar]

[bib25] 25. Mattes RD. Salt taste and hypertension: a critical review of the literature. J Chronic Dis. 1984;37(3):195–208. [DOI] [PubMed] [Google Scholar]

[bib26] 26. Jayasinghe SN, Kruger R, Walsh DC, Cao G, Rivers S, Richter M, Breier BH. Is sweet taste perception associated with sweet food liking and intake?. Nutrients. 2017;9(7):750. [DOI] [PMC free article] [PubMed] [Google Scholar]

[bib27] 27. Bertino M, Beauchamp GK, Engelman K. Increasing dietary salt alters salt taste preference. Physiol Behav. 1986;38(2):203–13. [DOI] [PubMed] [Google Scholar]

[bib28] 28. Walker RW, Goran MI. Laboratory determined sugar content and composition of commercial infant formulas, baby foods and common grocery items targeted to children. Nutrients. 2015;7(7):5850–67. [DOI] [PMC free article] [PubMed] [Google Scholar]

[bib29] 29. Food and Drug Administration. Code of Federal Regulations Title 21, nutrient content claims for the sodium content of food. [Internet]. [cited 27 August 2018]. Washington (DC)2017. Available from: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.61. [Google Scholar]

[bib30] 30. Schwartz MB, Vartanian LR, Wharton CM, Brownell KD. Examining the nutritional quality of breakfast cereals marketed to children. J Am Diet Assoc. 2008;108(4):702–5. [DOI] [PubMed] [Google Scholar]

[bib31] 31. Bobowski N, Vickers Z. Determining sequential difference thresholds for sodium chloride reduction. J Sens Stud. 2012;27(3):168–75. [Google Scholar]

[bib32] 32. Mennella JA, Lukasewycz LD, Griffith JW, Beauchamp GK. Evaluation of the Monell forced-choice, paired-comparison tracking procedure for determining sweet taste preferences across the lifespan. Chem Senses. 2011;36(4):345–55. [DOI] [PMC free article] [PubMed] [Google Scholar]

[bib33] 33. Bobowski NK, Mennella JA. Disruption in the relationship between blood pressure and salty taste thresholds among overweight and obese children. J Acad Nutr Diet. 2015;115(8):1272–82. [DOI] [PMC free article] [PubMed] [Google Scholar]

[bib34] 34. Harris JL, Schwartz MB, Ustjanauskas A, Ohri-Vachaspati P, Brownell KD. Effects of serving high-sugar cereals on children's breakfast-eating behavior. Pediatrics. 2011;127(1):71–6. [DOI] [PubMed] [Google Scholar]

[bib35] 35. Beauchamp GK, Cowart BJ. Preference for high salt concentrations among children. Dev Psychol. 1990;26(4):539. [Google Scholar]

[bib36] 36. Liem DG. Infants’ and children's salt taste perception and liking: a review. Nutrients. 2017;9(9):1011. [DOI] [PMC free article] [PubMed] [Google Scholar]

[bib37] 37. Gillette M. Flavor effects of sodium chloride. Food Technol. 1985;39(6):47–50. [Google Scholar]

[bib38] 38. Chen AW, Resurreccion A, Paguio LP. Age appropriate hedonic scales to measure food preferences of young children. J Sens Stud. 1996;11(2):141–63. [Google Scholar]

PERMALINK

Repeated Exposure to Low-Sodium Cereal Affects Acceptance but Does not Shift Taste Preferences or Detection Thresholds of Children in a Randomized Clinical Trial

Nuala Bobowski

Julie A Mennella