Na and K Content and Na/K Ratio of Ramen Dishes Served in Ramen Restaurants in Kyoto City, Japan
1
Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
2
Kirindo Co., Ltd., 4-5-36 Miyahara, Yodogawa-ku, Osaka 532-0003, Japan
3
The Research Institute of Strategy for Prevention, 10-14 Tomizawa-cho, Nihonbashi, Chuo-ku, Tokyo 103-0006, Japan
*
Author to whom correspondence should be addressed.
Dietetics 2025, 4(2), 21; https://doi.org/10.3390/dietetics4020021
Submission received: 24 January 2025
/
Revised: 14 February 2025
/
Accepted: 16 May 2025
/
Published: 3 June 2025
Abstract
:Salt intake, specifically NaCl, should be reduced to prevent hypertension. Ramen often contains high-NaCl soup in Japan, but there are no reports of the actual sodium (Na) or potassium (K) contents. We visited ramen restaurants in Kyoto that had received high ratings on review sites and sampled the soups and toppings (n = 52). The Na and K concentrations were measured using ion electrodes, and the NaCl and K contents per serving and Na/K ratio were calculated. The results were compared among different types of “tare” (thick seasonings) (salt, soy sauce, and miso) and different types of broth (chicken, pork bone, and fish). The average NaCl and K contents per serving were 6.53 ± 1.48 g and 448 ± 141 mg, respectively, and Na/K was 10.7 ± 4.3 mmol/mmol. Considering the different broths, the Na/K ratio was the lowest for fish (9.6 ± 5.2), followed by chicken (10.0 ± 3.1) and pork bone (13.2 ± 4.8). Ramen dishes were high in both Na and the Na/K ratio. The low Na/K of fish soup ramen was thought to be due to the higher K content extracted from dried fish. Depending on the broth, it is possible to reduce the Na/K ratio.
1. Introduction
High salt (NaCl) intake is prevalent in many countries, which may lead to hypertension and cardiovascular diseases [1,2]. However, the decreasing trend of salt intake of individuals is not clear in recent decades [3]. In many industrialized countries, the consumption of restaurant meals and processed foods is increasing while the consumption of home-cooked meals is decreasing [4,5]. Restaurant meals and processed foods are likely to contain high salt content in anticipation of customer preferences, whereas the use of high-salt condiments can be adjusted in home cooking. The reduction in salt content in restaurants and processed foods remains an important issue.
Although Japanese diets are often considered healthy because of their low fat content, they comprise higher salt contents than Western diets [6,7]; the average salt intake of adults was 9.8 g/day per capita in Japan in 2023 [8]. A previous study examining the association between 24 h urinary sodium (Na) excretion and food intake in Japan showed that people with higher urinary Na excretion were more likely to have a Japanese diet (i.e., higher rice and miso soup intake) [9]. Noodle intake, typically served in bowls with soup, known as ramen, soba, and udon, was also higher in the group with a higher urinary Na excretion. Notably, ramen restaurants are common in Japan, and although there are few survey results, the number of ramen restaurants in Japan was estimated to be around 15,000 to 25,000 [10,11]. A positive association between the number of ramen restaurants per capita and age-adjusted stroke mortality rate among prefectures in Japan was previously reported [12]. For people who habitually eat ramen, the salt content of the ramen may affect their salt intake, but there are few reports on the actual salt content. The salt content of miso soup, which is often eaten with Japanese food and contributes to salt intake in Japanese [9], was surveyed and reported to be 1.51% in the 1950s [13], and in a recent study, it was reported to be 1.0% [14]. It is also necessary to check the salt content of ramen.
Ramen noodles are served with toppings and soaked in soup, usually consumed alone without other dishes. Hence, ramen dishes generally contain insufficient amounts of vegetables, which are an important source of potassium (K) and recommended for hypertension prevention [15]. Furthermore, the average intake of K is lower in Japanese populations than in Western countries [6,7]; the average intake for Japanese adults was reported to be 2275 mg/day in 2023 [8], which has gradually been decreasing in recent years [16]. A previous study evaluating 24 h urinary K excretion found that people with lower K excretion were associated with higher noodle consumption [17]. To make the appropriate dietary choices, it is necessary to know the amount of K in foods. The foods that are high in K are vegetables, fruits, dairy products, and soy products [17], but there is little information about the amount of K in ramen served in restaurants.
In the present study, we estimated the Na and K contents per serving, as well as the Na/K ratio, based on measurements of the Na and K concentrations of ramen sampled from ramen restaurants in Kyoto City, Japan.
2. Materials and Methods
2.1. Selection of the Ramen Restaurants and Sampling
We used the online restaurant review website Tabelog.com provided by Kakaku.com, Inc. (Tokyo, Japan) to search for reputable ramen restaurants in Kyoto City (between July and December 2023). We visited the most reputable restaurants and bought soups and toppings from the restaurants that agreed to be measured, bringing these samples back to the laboratory. If ramen with different flavored soups was served, each ramen soup was obtained. We did not obtain noodles because they are starchy and difficult to measure using blended suspensions.
2.2. Measurements of Na and K
After separately weighing each serving of soup and topping, approximately 3 times the amount of water was added, and they were thoroughly ground in a blender. The aqueous component was obtained after centrifugation at 1500× g for 5 min and subjected to measurement using ion electrodes (LAQUAtwin Na-11 and LAQUAtwin K-11, Horiba, Ltd., Kyoto, Japan); calibrations were performed for each sample using standard solutions. Each sample was preliminarily diluted within the range of a suitable concentration for the measurement (300–500 ppm), and the concentration was determined using the recovery method. Each sample was measured twice, and the average values were used to calculate the NaCl and K contents per serving, as well as the Na/K ratio. For the calculations, 23.0, 39.1, and 35.5 were used as the atomic weights of Na, K, and Cl, respectively.
2.3. Statistics
At ramen restaurants, each restaurant makes the broth by boiling the ingredients. When serving ramen to customers, a soup is made by mixing “tare” (a high-salt seasoning) with broth. For the analysis, soups were classified according to the tare (salt, soy sauce, or miso) and the broth (chicken, pork bone, or fish). The classification of the ramen was determined by checking the menu or asking the restaurant staff. The distribution of the categorical variable was tested using Fisher’s exact test. The mean values of continuous variables were compared by analysis of variance with Bonferroni post hoc analysis. A p-value < 0.05 (two-sided) was considered significant. All statistical analyses were performed using SPSS V25 (IBM Japan Corp., Tokyo, Japan).
3. Results
A total of 34 ramen restaurants were visited and asked to participate. Among them, 24 agreed to cooperate, and we obtained 53 ramen samples (including soups and toppings). One sample could not be measured properly, and, thus, the results of 52 ramen measurements were used for the analysis. Table 1 shows the types of tare and soup broths. Soy sauce was the most common type of tare used (63.5%), whereas salt (29.2%) and miso (15.4%) were used less frequently. Chicken was the most common type of broth used (46.2%), followed by pork bone (34.6%) and fish (19.2%). There were no differences between the combinations of tare and broth (p = 0.192).
When all ramen samples (soup and topping) were averaged, the mean ± SD values for the NaCl (g) per serving, K (mg) per serving, and Na/K ratio (mmol/mmol) were 6.53 ± 1.48, 448 ± 141, and 10.7 ± 4.3, respectively. Table 2 shows the average NaCl and K contents, as well as the Na/K ratio, of the ramen soups and toppings according to the type of tare. Although the miso soup contained a higher amount of NaCl per serving (6.76 ± 1.76), there was no significant difference in the mean K content or the mean Na/K ratio among the three types of tare.
When classified according to the type of soup broth, significant differences were observed in the mean NaCl and K contents, as well as the Na/K ratio (Table 3). The mean NaCl per serving of pork bone soup (6.80 ± 1.36 g) was significantly higher than that of chicken soup (5.57 ± 1.26 g, p = 0.011) and fish soup (5.09 ± 1.01 g, p = 0.004). The mean K concentration was higher for fish soup (144 ± 79 mg/100g) than for pork bone soup (86 ± 32 mg/100g, p = 0.042) and chicken soup (93 ± 40.4 mg/100g, p = 0.109). The total amount of soup and topping per serving was the largest for pork bone ramen (460 ± 91 g), followed by chicken ramen (407 ± 57 g) and fish ramen (383 ± 51 g). The mean NaCl per serving of the total ramen (soup and toppings) was observed in the same order, with 7.56 ± 1.4, 6.12 ± 1.28, and 5.68 ± 1.06 g in each serving of pork bone-, chicken-, and fish-based ramen, respectively. Similarly, the Na/K ratio was the highest for pork bone ramen (13.2 ± 4.8), followed by chicken (10.0 ± 3.1) and fish (8.2 ± 3.8).
4. Discussion
This study focused on ramen, a popular dish among both Japanese citizens and foreigners visiting Japan, to determine the NaCl and K contents of the food served at restaurants. The average NaCl content per serving of ramen (soup and topping) was 6.53 g, which is higher than the target values reported by the World Health Organization (WHO; < 5 g/day) [18] and the Dietary Reference Intake for Japanese (DRIJ; < 6 g/day) [19]. The average K content was 448 mg/serving, which is lower than one-third, or one meal’s worth, of the target intake recommended by the WHO (3510 mg/day) [20] and DRIJ (3000 mg/day for men and 2600 mg/day for women) [19]. The average Na/K (mmol/mmol) of ramen was 10.7, which is higher than the average dietary Na/K of Japanese adults (2.9), calculated from results reported in the National Health and Nutrition Survey Japan in 2023 [8]. Overall, ramen is high in NaCl and has a high Na/K ratio; people who eat ramen may want to consider leaving the soup and eating dishes rich in K, such as vegetables, to help improve their Na/K ratio.
Herein, the ramen soups were classified into three categories according to tare and three categories according to broth. No difference in NaCl content or Na/K was observed based on the type of tare. However, there were differences in the NaCl content and Na/K of the soup depending on the broth. The NaCl concentration was higher in pork bone soup than in fish soup and chicken soup, and the K concentration was higher in fish soup. Differences in K concentrations may be related to differences in the broth ingredients. In fish broth, fish flakes, dried fish, and scraps are used, whereas pork bone broth and chicken broth are made from bones with bone marrow and a small amount of fatty tissue and skeletal muscle attached [21]. The K concentration is high in the intracellular fluid and is more abundant in muscle tissue than in adipose tissue in animals. Therefore, the use of fish flakes, dried fish, and scraps may have resulted in a higher K concentration in the fish broth. In addition, fish soup exhibited a lower NaCl concentration than other soups.
In recent years, large-scale intervention studies have been conducted using K-substitute salts, in which the NaCl is partially replaced with K-based salt, showing a blood pressure-lowering effect and cardiovascular disease prevention effect [22,23]. In these studies, using K-substitute salt may have made it possible to reduce the Na intake without making the food taste less salty, owing to the similar salty flavor of K-based salts [24]. In the present study, the NaCl concentration of the fish soup was lower than in other soups and the K concentration was higher, potentially because the saltiness of K-based compounds in the fish soup reduces the need for much salt. Previously, it was reported that using a strong bonito broth could reduce the salt content of miso soup [25], in which a simple conductivity meter was used, and the K concentration was not measured. The umami of bonito broth is often said to complement the saltiness, but bonito broth may have a high K concentration, and this may contribute to its flavor.
The use of K-substitute salts has been effective in intervention studies, and K substitution in other high-salt seasonings may also be effective. In Japan, a pilot intervention study was conducted on home-cooked meals using K-substitute seasonings (low-Na/K seasonings) for soy sauce and miso, and a significant decrease in the urinary Na/K ratio was reported [26]. Notably, ramen is a popular dish throughout Japan, and it is also one of the main menu items found in company and student cafeterias. In many cases, the ramen served in these cafeterias uses pre-made ramen soup produced by seasoning manufacturers. A previous study reported that using low-Na/K soy sauce and miso, as well as low-Na/K noodle soup, in Japanese company cafeterias may help reduce the intake of Na, increase the intake of K, and reduce the dietary Na/K ratio [27]. If even a partial amount of low-Na/K seasoning is used in the ramen soup at a ramen restaurant, it is possible to provide ramen that is more considerate of the customer’s health.
In this study, the noodles were not examined due to the difficulty in measuring their contents because of their high starch content. In ramen restaurants, they boil the raw ramen noodles in hot water without added salt, drain the water, and soak them in the soup. Raw ramen noodles contain a certain amount of NaCl (1.0 g/100 g) and K (350 mg/100 g) [28], but most of this dissolves into the hot water during the boiling process. Raw ramen noodle is commonly delivered to restaurants in bundles of one portion (usually 130g), and the one bundle of noodles is used for one serving of ramen dish. Thus, there should be no significant difference in the amount of noodles for one serving among ramen restaurants. The amount of NaCl and K contained in one portion of boiled ramen noodle (200 g) was estimated to be 0.4 g and 120 mg, respectively [28]. In this study, the amount of Na and K in the boiled noodles was not considered.
The soups and toppings contained a certain amount of fat depending on the ramen, but when the ground and diluted samples were centrifuged to collect the aqueous component for measurement, the oily part was not considered. Therefore, considering the potential fat content, the NaCl and K concentrations may be higher than the present estimates. However, this difference occurred equally across the measurements of Na and K in a given sample, and it should not affect the resulting Na/K ratio.
In 1950, regional differences in NaCl intake in Japan were significant, with 26 g/day reported for the northeast region and 14 g/day reported for the western region [29]. Although the difference has narrowed, there may still be a difference of around 1 g [30]. In prefectures with high NaCl intake [30], the age-adjusted mortality rate from stroke is relatively high [31], and these areas also correspond to areas with a high number of ramen restaurants per capita [12]. In the present study, we surveyed ramen restaurants in Kyoto City, often considered the gateway to western Japan, which is said to prefer relatively light flavors, but the potential differences among regions remain to be clarified. In each region of Japan, some types of ramen dishes are more popular, and most regions have a unique style, but the basic format (soup, toppings, and noodles) is the same. Hence, it should be possible to compare the amount of NaCl and K in a standardized way by obtaining the soup and toppings. If there are differences in the average NaCl content depending on the region, this may indicate the saltiness preferences of the people who live there.
In this study, we found that a single serving of ramen served in restaurants contains excessive salt and insufficient K and, therefore, may not be good for preventing hypertension. Furthermore, depending on the restaurant and the menu, some dishes may contain a lot of high-energy, saturated fatty acids, such as roasted pork or pork back fat. These characteristics may also affect blood pressure through obesity and atherosclerosis [32].
One of the strengths of this research is that we obtained actual dishes from ramen restaurants and directly measured the Na and K concentrations, considering that nutritional facts are not provided in most cases, except for large chain restaurants. In many reports concerning local NaCl reduction activities, the NaCl contents of miso soup have often been determined using a simple conductivity meter, and, therefore, the measurements were affected by other ions, such as K+ and Ca2+. Herein, we used ion electrode methods to selectively measure Na+ and K+, and we estimated the amount of NaCl and K per serving, as well as the Na/K ratio. One limitation of this study is that we chose ramen restaurants that had received high ratings on review sites. The results may have differed if we had included other ramen restaurants in the evaluation. Nonetheless, our results may reflect the saltiness preferences of the local people who eat at highly rated ramen restaurants. Furthermore, we did not consider the fat content of the soup or toppings. Given that fat intake is related to obesity and blood pressure elevation, further studies should consider fat content along with Na and K contents. Moreover, people do not always drink all of the soup in their ramen, and, thus, the actual amount of salt consumed by users may be less than the amount measured in this study.
5. Conclusions
The average NaCl content of a single serving of ramen from restaurants in Kyoto was as high as the daily target recommended by the WHO, and the Na/K ratio was also high. Comparing the different types of broth, the Na/K ratio of the fish soup was lower than that of the pork bone and chicken soups, likely due to the high K concentration of the fish-related ingredients. To help suppress the risk of elevated blood pressure, it may be effective to consider the type of broth, use low-Na/K seasonings, or increase the consumption of foods high in K. The amount of Na and K in other high-salt restaurant foods, such as udon noodles, also needs to be investigated in future research.
Author Contributions
Conceptualization, N.O. and A.O.; methodology, A.O.; formal analysis, N.O.; investigation, H.K.; data curation, N.O.; writing—original draft preparation, N.O.; writing—review and editing, T.N. and A.O.; supervision, A.O.; project administration, N.O.; funding acquisition, N.O. All authors have read and agreed to the published version of the manuscript.
Funding
This research was partially funded by a grant-in-aid for Scientific Research (C) from the Japan Society for the Promotion of Science (JSPS KAKENHI Grant Number 20K10510).
Institutional Review Board Statement
Not applicable.
Data Availability Statement
Data are available upon reasonable request.
Acknowledgments
The authors would like to thank the ramen restaurants that agreed to participate in the study and the late Kazuyoshi Itai for his support in planning the study.
Conflicts of Interest
The authors declare no conflicts of interest. Authors H.K. and A.O. are employed by companies Kirindo Co., Ltd. and The Research Institute of Strategy for Prevention, respectively. Authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Abbreviations
The following abbreviations are used in this manuscript:
| WHO | World Health Organization |
| DRIJ | Dietary Reference Intake for Japanese |
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Table 1.
Types of tare and broths used for the ramen soups.
| Type of Broth | p | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Chicken | Pork Bone | Fish | |||||||
| n | (%) | n | (%) | n | (%) | n | (%) | ||
| Type of tare | |||||||||
| Soy sauce | 15 | (62.5) | 12 | (66.7) | 6 | (60.0) | 0.192 | 33 | (63.5) |
| Salt | 7 | (29.2) | 1 | (5.6) | 3 | (30.0) | 11 | (21.2) | |
| Miso | 2 | (8.3) | 5 | (27.8) | 1 | (10.0) | 8 | (15.4) | |
| Total | 24 | (100.0) | 18 | (100.0) | 10 | (100.0) | 52 | (100.0) | |
p-value obtained using Fisher’s exact test.
Table 2.
NaCl and K content and Na/K ratio of ramen according to type of tare used for the soups.
| Soy Sauce (a) | Salt (b) | Miso (c) | p * | p ** | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| (n = 33) | (n = 11) | (n = 8) | a vs. b | b vs. c | a vs. c | |||||
| Mean | (SD) | Mean | (SD) | Mean | (SD) | |||||
| Soup | ||||||||||
| Amount per serving (g) | 331 | (50) | 290 | (51) | 329 | (52) | 0.067 | 0.070 | 0.285 | 1.000 |
| NaCl (g) | ||||||||||
| per 100 g | 1.83 | (0.44) | 1.75 | (0.28) | 2.06 | (0.40) | 0.240 | 1.000 | 0.302 | 0.494 |
| per serving | 5.95 | (1.23) | 5.10 | (1.46) | 6.76 | (1.61) | 0.034 | 0.223 | 0.031 | 0.398 |
| K (mg) | ||||||||||
| per 100 g | 91 | (39) | 107 | (45) | 101 | (29) | 0.467 | 0.725 | 1.000 | 1.000 |
| per serving | 294 | (120) | 309 | (138) | 331 | (103) | 0.731 | 1.000 | 1.000 | 1.000 |
| Na/K ratio (mmol/mmol) | 16.6 | (11.4) | 13.0 | (6.1) | 15.9 | (9.6) | 0.595 | 0.934 | 1.000 | 1.000 |
| Topping | ||||||||||
| Amount per serving (g) | 102 | (56) | 77 | (19) | 114 | (47) | 0.217 | 0.414 | 0.332 | 1.000 |
| NaCl (g) | ||||||||||
| per 100 g | 0.69 | (0.34) | 0.89 | (0.49) | 0.70 | (0.35) | 0.309 | 0.397 | 0.869 | 1.000 |
| per serving | 0.60 | (0.27) | 0.64 | (0.36) | 0.81 | (0.63) | 0.332 | 1.000 | 0.888 | 0.418 |
| K (mg) | ||||||||||
| per 100 g | 156 | (59) | 201 | (70) | 128 | (40) | 0.029 | 0.110 | 0.033 | 0.681 |
| per serving | 145 | (60) | 149 | (49) | 139 | (57) | 0.930 | 1.000 | 1.000 | 1.000 |
| Na/K ratio (mmol/mmol) | 3.3 | (2.3) | 3.1 | (1.7) | 3.9 | (2.1) | 0.687 | 1.000 | 1.000 | 1.000 |
| Total (soup and topping) | ||||||||||
| Amount per serving (g) | 433 | (72) | 366 | (62) | 443 | (75) | 0.021 | 0.027 | 0.069 | 1.000 |
| NaCl (g) | ||||||||||
| per 100 g | 1.53 | (0.31) | 1.56 | (0.24) | 1.72 | (0.34) | 0.320 | 1.000 | 0.803 | 0.402 |
| per serving | 6.55 | (1.29) | 5.74 | (1.41) | 7.57 | (1.83) | 0.026 | 0.309 | 0.022 | 0.216 |
| K (mg) | ||||||||||
| per 100 g | 103 | (37) | 127 | (36) | 108 | (26) | 0.165 | 1.000 | 1.000 | 1.000 |
| per serving | 439 | (154) | 459 | (126) | 471 | (106) | 0.826 | 1.000 | 1.000 | 1.000 |
| Na/K ratio (mmol/mmol) | 11.1 | (4.2) | 9.0 | (3.5) | 11.6 | (5.1) | 0.293 | 0.461 | 0.553 | 1.000 |
*, obtained by analysis of variance; **, obtained by Bonferroni post hoc analysis.
Table 3.
NaCl and K content and Na/K ratio of ramen according to the type of broth used for the soups.
Table 3.
NaCl and K content and Na/K ratio of ramen according to the type of broth used for the soups.
| Chicken (a) | Pork Bone (b) | Fish (c) | p * | p ** | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| (n = 24) | (n = 18) | (n = 10) | a vs. b | b vs. c | a vs. c | |||||
| Mean | (SD) | Mean | (SD) | Mean | (SD) | |||||
| Soup | ||||||||||
| Amount per serving (g) | 322 | (55) | 335 | (52) | 298 | (42) | 0.108 | 1.000 | 0.240 | 0.706 |
| NaCl (g) | ||||||||||
| per 100 g | 1.76 | (0.42) | 2.04 | (0.36) | 1.6 | (0.56) | 0.026 | 0.087 | 0.148 | 1.000 |
| per serving | 5.57 | (1.26) | 6.80 | (1.36) | 5.09 | (1.01) | 0.006 | 0.011 | 0.004 | 0.944 |
| K (mg) | ||||||||||
| per 100 g | 93 | (40) | 86 | (32) | 144 | (79) | 0.001 | 1.000 | 0.042 | 0.109 |
| per serving | 290 | (111) | 284 | (110) | 411 | (192) | 0.027 | 1.000 | 0.212 | 0.225 |
| Na/K ratio (mmol/mmol) | 14.9 | (7.3) | 19.8 | (13.9) | 9.6 | (5.2) | 0.028 | 0.329 | 0.056 | 0.711 |
| Topping | ||||||||||
| Amount per serving (g) | 85 | (41) | 125 | (61) | 85 | (23) | 0.018 | 0.025 | 0.101 | 1.000 |
| NaCl (g) | ||||||||||
| per 100 g | 0.71 | (0.38) | 0.74 | (0.39) | 0.77 | (0.40) | 0.926 | 1.000 | 1.000 | 1.000 |
| per serving | 0.55 | (0.29) | 0.79 | (0.46) | 0.59 | (0.22) | 0.090 | 0.100 | 0.008 | 1.000 |
| K (mg) | ||||||||||
| per 100 g | 184.2 | (59.4) | 117.3 | (37.3) | 185.5 | (67.9) | < 0.001 | 0.001 | 0.008 | 1.000 |
| per serving | 149.1 | (58.2) | 135.1 | (56.9) | 152.2 | (53.5) | 0.663 | 1.000 | 1.000 | 1.000 |
| Na/K ratio (mmol/mmol) | 2.7 | (1.4) | 4.2 | (2.2) | 3.3 | (3.0) | 0.067 | 0.063 | 0.725 | 1.000 |
| Total (soup and topping) | ||||||||||
| Amount per serving (g) | 407 | (57) | 460 | (91) | 383 | (51) | 0.013 | 0.055 | 0.023 | 1.000 |
| NaCl (g) | ||||||||||
| per 100 g | 1.51 | (0.25) | 1.68 | (0.4) | 1.49 | (0.29) | 0.051 | 0.213 | 0.339 | 1.000 |
| per serving | 6.12 | (1.28) | 7.56 | (1.4) | 5.68 | (1.06) | < 0.001 | 0.003 | 0.002 | 1.000 |
| K (mg) | ||||||||||
| per 100 g | 109.8 | (35.0) | 92.9 | (26.2) | 136.3 | (39.5) | 0.041 | 0.328 | 0.005 | 0.116 |
| per serving | 438.8 | (132.3) | 419.6 | (121.0) | 522.3 | (177.9) | 0.164 | 1.000 | 0.197 | 0.344 |
| Na/K ratio (mmol/mmol) | 10.0 | (3.1) | 13.2 | (4.8) | 8.2 | (3.8) | 0.004 | 0.036 | 0.006 | 0.661 |
*, obtained by analysis of variance; **, obtained by Bonferroni post hoc analysis.
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MDPI and ACS Style
Okuda, N.; Kojima, H.; Nagahata, T.; Okayama, A. Na and K Content and Na/K Ratio of Ramen Dishes Served in Ramen Restaurants in Kyoto City, Japan. Dietetics 2025, 4, 21. https://doi.org/10.3390/dietetics4020021
AMA Style
Okuda N, Kojima H, Nagahata T, Okayama A. Na and K Content and Na/K Ratio of Ramen Dishes Served in Ramen Restaurants in Kyoto City, Japan. Dietetics. 2025; 4(2):21. https://doi.org/10.3390/dietetics4020021
Chicago/Turabian StyleOkuda, Nagako, Hiroko Kojima, Tomomi Nagahata, and Akira Okayama. 2025. "Na and K Content and Na/K Ratio of Ramen Dishes Served in Ramen Restaurants in Kyoto City, Japan" Dietetics 4, no. 2: 21. https://doi.org/10.3390/dietetics4020021
APA StyleOkuda, N., Kojima, H., Nagahata, T., & Okayama, A. (2025). Na and K Content and Na/K Ratio of Ramen Dishes Served in Ramen Restaurants in Kyoto City, Japan. Dietetics, 4(2), 21. https://doi.org/10.3390/dietetics4020021
