Nutr Res Pract.  2013 Feb;7(1):59-65.

Salt content of school meals and comparison of perception related to sodium intake in elementary, middle, and high schools

• Ahn S
• Park S
• Kim JN
• Han SN
• Jeong SB
• Kim HK

Abstract

Excessive sodium intake leading to hypertension, stroke, and stomach cancer is mainly caused by excess use of salt in cooking. This study was performed to estimate the salt content in school meals and to compare differences in perceptions related to sodium intake between students and staffs working for school meal service. We collected 382 dishes for food from 24 schools (9 elementary, 7 middle, 8 high schools) in Gyeonggi-do and salt content was calculated from salinity and weight of individual food. The average salt content from elementary, middle, and high school meals were 2.44 g, 3.96 g, and 5.87 g, respectively. The amount of salt provided from the school lunch alone was over 80% of the recommended daily salt intake by WHO. Noodles, stews, sauces, and soups were major sources of salt intake at dish group level, while the most salty dishes were sauces, kimchies, and stir-fried foods. Dietary knowledge and attitude related to sodium intake and consumption frequency of the salty dishes were surveyed with questionnaire in 798 students and 256 staffs working for school meal service. Compared with the staffs, the students perceived school meals salty and the proportions of students who thought school meals were salty increased with going up from elementary to high schools (P < 0.001). Among the students, middle and high school students showed significant propensity for the preference to one-dish meal, processed foods, eating much broth and dipping sauce or seasoning compared with the elementary students, although they had higher nutrition knowledge scores. These results proposed that monitoring salt content of school meals and consideration on the contents and education methods in school are needed to lower sodium intake.

Keyword

School meal; salt content; sodium intake; saltiness perception

MeSH Terms

Cooking
Eating
Humans
Hypertension
Lunch
Meals
Surveys and Questionnaires
Salinity
Seasons
Sodium
Stomach Neoplasms
Stroke
Sodium

Figure

• 

  Fig. 1 Salinity and contribution rate of individual dish group in school meals

Reference

1. Stamler J. The INTERSALT study: background, methods, findings, and implications. Am J Clin Nutr. 1997. 65:626S–642S.

2. Nagata C, Takatsuka N, Shimizu N, Shimizu H. Sodium intake and risk of death from stroke in Japanese men and women. Stroke. 2004. 35:1543–1547.

3. Joossens JV, Hill MJ, Elliott P, Stamler R, Lesaffre E, Dyer A, Nichols R, Kesteloot H. European Cancer Prevention (ECP) and the INTERSALT Cooperative Research Group. Dietary salt, nitrate and stomach cancer mortality in 24 countries. Int J Epidemiol. 1996. 25:494–504.

4. Intersalt Cooperative Research Group. Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. BMJ. 1988. 297:319–328.

5. Ministry of Health and Welfare, Korea Centers for Disease Control and Prevention. National Health Statistics - The 5th Korea National Health & Nutrition Examination Survey (KNHANES V). 2010. Cheongwon: Korea Centers for Disease Control and Prevention.

6. The Korean Nutrition Society. Dietary Reference Intakes for Koreans. 2010. Seoul: The Korean Nutrition Society.

7. Kannel WB. Blood pressure as a cardiovascular risk factor: prevention and treatment. JAMA. 1996. 275:1571–1576.

8. Midgley JP, Matthew AG, Greenwood CM, Logan AG. Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials. JAMA. 1996. 275:1590–1597.

9. He FJ, MacGregor GA. Effect of modest salt reduction on blood pressure: a meta-analysis of randomized trials. Implications for public health. J Hum Hypertens. 2002. 16:761–770.

10. Paik HY. Nutritional aspects for salt. Proceedings of the Korean Society of Food and Cookery Science Conference. 1987. 1987 April; 92–106.

11. Chauncey HH, Wallace S, Alman JE. Kare MR, Fregly MJ, Bernard RA, editors. Salivary chloride levels, taste thresholds for salt, and food ingestion. Biological and Behavioral Aspects of Salt Intake. 1980. New York: Academic Press;113–125.

12. Pangborn RM, Pecore SD. Taste perception of sodium chloride in relation to dietary intake of salt. Am J Clin Nutr. 1982. 35:510–520.

13. Hooper L, Bartlett C, Davey Smith G, Ebrahim S. Systematic review of long term effects of advice to reduce dietary salt in adults. BMJ. 2002. 325:628.

14. He J, Whelton PK, Appel LJ, Charleston J, Klag MJ. Long-term effects of weight loss and dietary sodium reduction on incidence of hypertension. Hypertension. 2000. 35:544–549.

15. Jung HR, Lee MJ, Kim KC, Kim JB, Kim DH, Kang SH, Park JS, Kwon KI, Kim MH, Park YB. Survey on the sodium contents of nursery school meals in Gyeonggi-do. J Korean Soc Food Sci Nutr. 2010. 39:526–534.

16. Lee H, Lee C, Lee K, Jung Y, Ha S, Jung Y, Kim D. Survey on sodium contents in meals of school foodservice and sodium intakes of students in Busan and Gyeongsangbuk-do. J Korean Soc Food Sci Nutr. 2010. 39:85–91.

17. Lee S, Chang E, Choi J, Bahn K, Kim M. Current assessment of sodium and potassium intakes in elementary and middle school students through school meals. Korean J Food Sci Technol. 2010. 42:578–585.

18. Yon M, Lee Y, Kim D, Lee J, Koh E, Nam E, Shin H, Kang BW, Kim JW, Heo S, Cho HY, Kim CI. Major sources of sodium intake of the Korean population at prepared dish level -based on the KNHANES 2008 & 2009-. Korean J Community Nutr. 2011. 16:473–487.

19. Clark MA, Fox MK. Nutritional quality of the diets of US public school children and the role of the school meal programs. J Am Diet Assoc. 2009. 109:S44–S56.

20. Park HR, Jeong GO, Lee SL, Kim JY, Kang SA, Park KY, Ryou HJ. Workers intake too much salt from dishes of eating out and food service cafeterias; direct chemical analysis of sodium content. Nutr Res Pract. 2009. 3:328–333.

21. National Academy of Agricultural Science [Internet]. 2012. cited 2012 October 1. Suwon: National Academy of Agricultural Science;Available from: http://koreanfood.rda.go.kr/fct/FctFoodSrch.aspx.

22. Jung YY, Shin EK, Lee HJ, Lee NH, Chun BY, Ann MY, Lee YK. Development and evaluation of a nutrition education program on sodium reduction in elementary school students. Korean J Community Nutr. 2009. 14:746–755.

23. Choi BS, Kim EJ, Park YS. Study on sodium intake and preference for salty taste in college women. J Korean Soc Food Sci Nutr. 1997. 26:154–160.

24. Kim KO, Hwang IK. A study on salt taste preference and food habits. Saenghwalgwahagyeongu. 1992. 17:61–64.