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Sandwiches Are Major Contributors of Sodium in the Diets of American Adults: Results from What We Eat in America, National Health and Nutrition Examination Survey 2009-2010

Published:October 05, 2014DOI:https://doi.org/10.1016/j.jand.2014.07.034

      Abstract

      Efforts to sharpen the focus of sodium reduction strategies include identification of major food group contributors of sodium intake. Although sandwiches are a staple of the American diet, previous examinations of their contribution to sodium intake captured only a small subset of sandwiches. One day of dietary intake data from 5,762 adults aged 20 years and older in What We Eat in America, National Health and Nutrition Examination Survey 2009-2010 was analyzed. Sandwiches were defined in a manner that more accurately reflected their frequency of consumption. Two-sided t tests were used to compare percentages of men and women reporting sandwiches; contributions of sandwiches to energy and sodium intakes (amounts in kilocalories and milligrams, respectively, and percent of daily totals) by sex; and total energy, total sodium, and sodium density (mg/1,000 kcal) by sandwich reporting status (reporter/nonreporter). On any given day, 49% of American adults ate sandwiches. A significantly higher percentage of men than women reported sandwiches (54% vs 44%, respectively; P<0.001), and sandwiches accounted for higher percentages of men’s total energy and sodium intakes. Compared with individuals who did not report a sandwich on the intake day, sandwich reporters had significantly higher energy and sodium intakes; however, sodium density of the diet did not vary by sandwich reporting status. Although much national attention is appropriately focused on reducing sodium in the food supply, consumer choices still play a vital role. Due to sandwiches’ frequent consumption and considerable contributions to sodium intake, substituting lower-sodium for higher-sodium ingredients in sandwiches could significantly influence sodium intakes.

      Keywords

      Sodium intake by Americans is considerably higher than national recommendations.
      • Sebastian R.S.
      • Wilkinson Enns C.
      • Steinfeldt L.C.
      • Goldman J.D.
      • Moshfegh A.J.
      Monitoring sodium intake of the US population: Impact and implications of a change in What We Eat in America, National Health and Nutrition Examination Survey dietary data processing.

      US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans 2010. 7th ed. Washington, DC: US Government Printing Office; 2010.

      The Institute of Medicine determined that achieving lower sodium intakes in the US population is a critical public health focus necessitating new government standards for sodium intake, reductions in the sodium content of foods by manufacturers and restaurants, and efforts to support consumers in making behavior changes.
      Institute of Medicine Committee on Strategies to Reduce Sodium Intake
      To inform public health efforts by increasing understanding of eating behavior, researchers have identified food categories that make significant contributions to sodium intake of different populations.
      • Fischer P.W.
      • Vigneault M.
      • Huang R.
      • Arvaniti K.
      • Roach P.
      Sodium food sources in the Canadian diet.
      • Anderson C.A.
      • Appel L.J.
      • Okuda N.
      • et al.
      Dietary sources of sodium in China, Japan, the United Kingdom, and the United States, women and men aged 40 to 59 years: The INTERMAP study.
      • Hoy M.K.
      • Goldman J.D.
      • Murayi T.
      • Rhodes D.G.
      • Moshfegh A.J.
      Sodium Intake of the U.S. Population: What We Eat In America, NHANES 2007-2008.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Drewnowski A.
      • Rehm C.D.
      Sodium intakes of US children and adults from foods and beverages by location of origin and by specific food source.
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.
      • de Moura Souza A.
      • Bezerra I.N.
      • Pereira R.A.
      • Peterson K.E.
      • Sichieri R.
      Dietary sources of sodium intake in Brazil in 2008-2009.
      • O'Neil C.E.
      • Keast D.R.
      • Fulgoni V.L.
      • Nicklas T.A.
      Food sources of energy and nutrients among adults in the US: NHANES 2003-2006.
      A relatively small number of food categories contribute a large portion of the total daily sodium intake. Two studies using slightly different food groups reported that 10 food categories accounted for 44%
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      and 66%
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.
       of total sodium intake. Ranked among the top food group contributors to sodium are many common sandwich ingredients—for example, bread, cold cuts, and cheese.
      • Fischer P.W.
      • Vigneault M.
      • Huang R.
      • Arvaniti K.
      • Roach P.
      Sodium food sources in the Canadian diet.
      • Anderson C.A.
      • Appel L.J.
      • Okuda N.
      • et al.
      Dietary sources of sodium in China, Japan, the United Kingdom, and the United States, women and men aged 40 to 59 years: The INTERMAP study.
      • Hoy M.K.
      • Goldman J.D.
      • Murayi T.
      • Rhodes D.G.
      • Moshfegh A.J.
      Sodium Intake of the U.S. Population: What We Eat In America, NHANES 2007-2008.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Drewnowski A.
      • Rehm C.D.
      Sodium intakes of US children and adults from foods and beverages by location of origin and by specific food source.
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.
      • de Moura Souza A.
      • Bezerra I.N.
      • Pereira R.A.
      • Peterson K.E.
      • Sichieri R.
      Dietary sources of sodium intake in Brazil in 2008-2009.
      • O'Neil C.E.
      • Keast D.R.
      • Fulgoni V.L.
      • Nicklas T.A.
      Food sources of energy and nutrients among adults in the US: NHANES 2003-2006.
      The few studies that included sandwiches per se as a food group found them also to be among the top contributors of sodium.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.
      It is noteworthy that in those studies only foods that were represented by a single food code denoting a sandwich were categorized as sandwiches. Thus, it may be that substantial proportions of the bread, cheese, and cold cuts in those studies were actually consumed as sandwich ingredients.
      Several of those studies used dietary data from What We Eat in America (WWEIA), the dietary intake interview component of the National Health and Nutrition Examination Survey (NHANES).
      • Hoy M.K.
      • Goldman J.D.
      • Murayi T.
      • Rhodes D.G.
      • Moshfegh A.J.
      Sodium Intake of the U.S. Population: What We Eat In America, NHANES 2007-2008.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Drewnowski A.
      • Rehm C.D.
      Sodium intakes of US children and adults from foods and beverages by location of origin and by specific food source.
      • O'Neil C.E.
      • Keast D.R.
      • Fulgoni V.L.
      • Nicklas T.A.
      Food sources of energy and nutrients among adults in the US: NHANES 2003-2006.
      In WWEIA data files, many sandwiches (often fast-food items) are represented by a single food code, such as the code described as “Cheeseburger with tomato and/or catsup, on bun.” These are referred to as “single-code sandwiches.” Other sandwiches are represented in the data by two or more food codes that are linked and identified as a “sandwich combination.” For example, if a respondent reported a tomato sandwich, the food would be represented by several lines of data (eg, bread, tomato, lettuce, and spread) linked as a sandwich combination. Sandwich combinations are an untapped resource that can enhance our knowledge of the context in which sodium is being consumed.
      The objectives of our study were to examine and contrast men and women in terms of sandwich reporting and the contributions to energy and sodium intakes (discrete amounts and percentages of daily totals) from sandwiches, and determine whether sandwich reporting status (reporter/nonreporter) was associated with energy and/or sodium intake or with sodium density (mg/1,000 kcal). To better assess the magnitude of sandwiches’ influence on sodium intake, the definition of sandwiches included both sandwich combinations and single-code sandwiches.

      Methods

      Sample

      Estimates were based on 1-day data from 5,762 adults aged 20 years and older (2,973 women and 2,789 men) with a complete 24-hour recall in WWEIA, NHANES 2009-2010,

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      the most recent nationwide dietary intake data available at the time of the study. NHANES used a complex, multistage probability sampling design to select a sample representative of the civilian, non-institutionalized household population of the United States,

      Centers for Disease Control and Prevention, National Center for Health Statistics. NHANES 2009-2010 Public Data General Release File Documentation. http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/generaldoc_f.htm. Published September 2011. Accessed September 10, 2013.

      Zipf G, Chiappa M, Porter KS, Ostchega Y, Lewis BG, Dostal J. National Health and Nutrition Examination Survey: Plan and operations, 1999-2010. http://www.cdc.gov/nchs/data/series/sr_01/sr01_056.pdf. Published August 2013. Accessed April 10, 2014.

      with oversampling of people aged 60 years and older, low-income people, non-Hispanic blacks, and Hispanics to improve the accuracy of related estimates.

      Centers for Disease Control and Prevention, National Center for Health Statistics. NHANES 2009-2010 Public Data General Release File Documentation. http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/generaldoc_f.htm. Published September 2011. Accessed September 10, 2013.

      The survey protocol was reviewed and approved by the National Center for Health Statistics Research Ethics Review Board. Our study was a secondary analysis and was deemed exempt from further review under federal regulation 45 CFR 46.101(b).

      Dietary Intake Data Collection and Coding

      Dietary intake data were collected using the US Department of Agriculture (USDA) Automated Multiple-Pass Method for the 24-hour recall (AMPM).
      • Moshfegh A.J.
      • Rhodes D.G.
      • Baer D.J.
      • et al.
      The US Department of Agriculture Automated Multiple-Pass Method reduces bias in the collection of energy intakes.

      USDA Food Surveys Research Group. USDA Automated Multiple-Pass Method. http://www.ars.usda.gov/Services/docs.htm?docid=7710. Published September 29, 2010. Accessed September 10, 2013.

      • Raper N.
      • Perloff B.
      • Ingwersen L.
      • Steinfeldt L.
      • Anand J.
      An overview of USDA’s Dietary Intake Data System.
      Recalls were conducted by trained interviewers fluent in English and Spanish.

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      We used the first day of intake data, which was collected in person. Though attempts had been made to schedule interviews uniformly throughout the week, proportionally more intakes occurred on weekend days than on weekdays, resulting in more recall days being Fridays and Saturdays.

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      WWEIA 2009-2010 dietary intake data are available online.

      Centers for Disease Control, National Center for Health Statistics. NHANES 2009-2010 Dietary Data. http://wwwn.cdc.gov/nchs/nhanes/search/datapage.aspx?Component=Dietary&CycleBeginYear=2009. Updated August 20, 2013. Accessed September 10, 2013.

      All foods reported in WWEIA, NHANES 2009-2010 were coded using one or more USDA food codes from the USDA Food and Nutrient Database for Dietary Studies (FNDDS; version 5.0, 2012 [updated 2013], USDA). Most foods are assigned a single food code. However, it is not feasible to include in the FNDDS a precise match for every possible permutation of the way people eat foods. For that reason, food codes may be linked in “combinations” to represent foods that are ingredients in a multi-ingredient food, such as bread, egg, cheese, vegetables, and spread in a sandwich.

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      • Raper N.
      • Perloff B.
      • Ingwersen L.
      • Steinfeldt L.
      • Anand J.
      An overview of USDA’s Dietary Intake Data System.
      Although more than 200 food codes representing sandwiches are available in FNDDS 5.0 (for example, USDA food code 27540350, “Turkey submarine sandwich with cheese, lettuce, tomato, and spread”), most sandwiches are coded as sandwich ingredients linked together in combinations.
      The AMPM question sequence for sandwiches asks whether the sandwich was homemade or from a fast-food restaurant, school cafeteria, or another place. The majority of fast-food sandwiches were coded with a food code that falls into the WWEIA Food Category named “Mixed dishes—sandwiches (single code).”

      USDA Food Surveys Research Group. Dietary methods research: Overview of the What We Eat in America Food Categories. http://www.ars.usda.gov/Services/docs.htm?docid=23429. Published July 8, 2013. Accessed September 10, 2013.

      However, it was necessary to code others using multiple food codes linked together to achieve a good match for the nutrient profile of the sandwich. For sandwiches obtained from any place besides a fast-food restaurant, the AMPM asks for full details, including separate amounts, for all components. When the respondent provides this information, each sandwich ingredient is coded with its own food code and amount, a combination food number is assigned to identify that the components were all part of the sandwich, and a value of 5 for the combination food type variable is assigned.

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      • Raper N.
      • Perloff B.
      • Ingwersen L.
      • Steinfeldt L.
      • Anand J.
      An overview of USDA’s Dietary Intake Data System.

      Definition of a Sandwich

      In our study, sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File with food codes that fell into the WWEIA Food Category “Mixed dishes—sandwiches (single code)”

      USDA Food Surveys Research Group. Dietary methods research: Overview of the What We Eat in America Food Categories. http://www.ars.usda.gov/Services/docs.htm?docid=23429. Published July 8, 2013. Accessed September 10, 2013.

      and/or that were consumed as part of a sandwich combination.
      Although this definition did not require that sandwich combinations contain a bread-type item, nearly all (>99%) did. Through a detailed examination of the line items in each combination, we reviewed all sandwich combinations to verify that they appeared similar to the foods included in the WWEIA food category “Mixed dishes—sandwiches (single-code).” We excluded a small number of combinations whose ingredients suggested they would have been more appropriately categorized as tortilla product combinations (combination type 11) based on unpublished internal instructions to food coders (USDA Food Surveys Research Group, February 2009). Ingredients of nonsandwich combinations were also reviewed to determine whether they contained sandwich-type ingredients, and a few such combinations (eg, bratwurst and bread) were included as sandwiches.

      Statistical Analysis

      Analyses were carried out using SAS release 9.3 (2011, SAS Institute Inc). SUDAAN release 11.0 (2012, Research Triangle Institute) was used to adjust for survey design effects resulting from NHANES’ complex, multistage probability sampling.

      Centers for Disease Control and Prevention, National Center for Health Statistics. NHANES 2009-2010 Public Data General Release File Documentation. http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/generaldoc_f.htm. Published September 2011. Accessed September 10, 2013.

      All analyses used sample weights to produce nationally representative estimates.
      All estimates were calculated by age for all adults collectively and for men and women separately.
      Descriptive statistics included percentages reporting sandwiches, amounts of energy (kilocalories) and sodium (milligrams) provided by sandwich intake, and percentages of total energy and sodium intake contributed by sandwiches. To detect differences between men and women within age group in percentages reporting, mean intakes, and percentage contributions to total daily intakes of energy and sodium, t tests were used.
      Total intakes of energy and sodium from all foods and beverages were calculated for sandwich reporters and nonreporters. Linear regression was used to provide estimates adjusted for variables related to dietary intake. Adjustment variables examined were age; race/ethnicity; income as a percentage of poverty

      US Department of Commerce, US Census Bureau. Poverty thresholds. http://www.census.gov/hhes/www/poverty/data/threshld/. Updated September 17, 2013. Accessed September 17, 2013.

      ; weight status

      Centers for Disease Control and Prevention. Defining overweight and obesity. http://www.cdc.gov/obesity/adult/defining.html. Updated April 27, 2012. Accessed August 14, 2013.

      ; smoking status (never, former, or current); and physical activity level (<150 minutes, 150 to 299 minutes, or ≥300 minutes of moderate activity per week).

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey 2009-2010 Data Documentation, Codebook, and Frequencies: Physical Activity (PAQ_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/PAQ_F.htm. Published September 2011. Accessed August 15, 2013.

      US Department of Health and Human Services. Physical Activity Guidelines for Americans: Appendix 1. Translating scientific evidence about total amount and intensity of physical activity into guidelines. http://www.health.gov/paguidelines/guidelines/appendix1.aspx. Updated October 16, 2008. Accessed August 14, 2013.

      Both unadjusted and adjusted estimates were compared between sandwich reporters and nonreporters (all adults, men, and women by age) with t tests. Similarly, sodium density (mg/1,000 kcal) of food/beverage intake was calculated for sandwich reporters and nonreporters. Unadjusted and adjusted estimates were contrasted by sandwich reporting status.
      Findings of significance were the same regardless of whether unadjusted or adjusted estimates of energy intake, sodium intake, and sodium density were compared between sandwich reporters and nonreporters, so only unadjusted results are presented.
      All P values presented apply to two-sided tests. Because multiple comparisons were performed, a significance level of P<0.001 was used in lieu of a Bonferroni-type correction to reduce the chance of a type I error.

      Results and Discussion

      During 2009-2010, only about 20% of all sandwiches were represented by a single food code (data not shown). For that reason, previously published estimates of sandwich contributions to sodium intakes that were based on only single-code sandwiches are considerable underestimates.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.
      Nearly half of American adults (49%) ate a sandwich on the intake day (Table 1). A significantly larger percentage of men aged 20 years and older than of women the same age reported at least one sandwich, reflecting the significant differences seen in the middle-aged (40 to 59 years) and older (60 years and older) groups.
      Table 1Sandwiches
      Sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File that were assigned food codes that fell into the WWEIA Food Category “Mixed Dishes—sandwiches (single code)”19 and/or consumed as part of a sandwich combination (indicated by a value of 5 for the “combination food type” variable12).
      : Percent reporting and contributions to mean daily total intakes of energy and sodium, adults aged 20 years and older, What We Eat in America, National Health and Nutrition Examination Survey (WWEIA, NHANES) 2009-2010, 1 day
      Sample weights designed for dietary analysis were used to produce estimates representative of the US population for the years of collection.
      Sex and age (y)n
      Unweighted.
      Sandwich reporters %±SE
      SE=standard error.
      Energy Contribution of SandwichesSodium Contribution of Sandwiches
      Kilocalories±SE% of total energy±SEMilligrams±SE% of total sodium±SE
      Men
      20-3990551±2.7372±24.114±0.8955±69.921±1.5
      40-5995157±2.7367±23.714±0.8963±65.322±1.3
      60+93353±2.8283±17.214±0.7710±41.620±1.1
       Total 20+2,78954±2.0350±14.314±0.5902±34.421±0.7
      Women
      20-391,02349±2.8241±17.5
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      13±0.9595±39.5
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      19±1.3
      40-5998440±2.8
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      184±15.7
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      10±0.8446±39.2
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      15±1.2
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      60+96644±2.5
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      167±12.8
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      10±0.7
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      408±28.6
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      15±0.9
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
       Total 20+2,97344±2.2
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      200±10.6
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      11±0.6
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      489±27.2
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      16±0.9
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      All
      20-391,92850±2.1307±16.113±0.7776±43.420±1.2
      40-591,93548±2.4272±16.113±0.7696±44.719±1.2
      60+1,89948±2.4219±14.212±0.7543±32.617±1.0
       Total 20+5,76249±1.9272±10.813±0.5688±27.119±0.7
      a Sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File that were assigned food codes that fell into the WWEIA Food Category “Mixed Dishes—sandwiches (single code)”

      USDA Food Surveys Research Group. Dietary methods research: Overview of the What We Eat in America Food Categories. http://www.ars.usda.gov/Services/docs.htm?docid=23429. Published July 8, 2013. Accessed September 10, 2013.

      and/or consumed as part of a sandwich combination (indicated by a value of 5 for the “combination food type” variable

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      ).
      b Sample weights designed for dietary analysis were used to produce estimates representative of the US population for the years of collection.
      c Unweighted.
      d SE=standard error.
      Percentage or mean contribution differs significantly from that of men in the same age group (P<0.001).
      The mean contribution of sandwiches to energy intakes of all adults (ie, sandwich reporters and nonreporters combined) was 350 kcal for men and 200 kcal for women. This is 14% and 11% of total energy intake for men and women, respectively.
      Estimates of mean total energy and sodium intake per day by sex and age, race/ethnicity, and income (in dollars and as percent of poverty) are available at http://www.ars.usda.gov/Services/docs.htm?docid=18349.
      The mean contribution of sandwiches to men’s sodium intake was 902 mg. This is 39% of the 2010 Dietary Guidelines for Americans (DGA) daily limit of 2,300 mg recommended for Americans in general and 60% of the stricter limit for adults older than age 50 years, African Americans, and people with diabetes, hypertension, or chronic kidney disease.

      US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans 2010. 7th ed. Washington, DC: US Government Printing Office; 2010.

      Women’s intake of sodium from sandwiches (489 mg), although significantly lower than men’s, was still considerable. This difference by sex is probably due at least in part to women’s lower food intake overall and the lower percentage of women consuming sandwiches. Sandwiches provide 21% of men’s and 16% of women’s overall sodium intake. These levels are much higher than the 3.9% reported as being contributed by single-code sandwiches.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      Mean daily total energy and sodium intake estimates for sandwich reporters and nonreporters appear in Table 2. In the “Total 20+” groups of men, women, and all adults, both energy and sodium intakes were significantly higher for sandwich reporters than for nonreporters. All sex and age groups of both reporters and nonreporters had mean sodium intakes that exceeded the DGA recommendation of 2,300 mg per day. Sodium intake by male sandwich reporters aged 20 years and older was 4,541 mg, nearly twice the 2,300 mg recommendation. The difference in mean daily sodium intake between male sandwich reporters and nonreporters aged 20 years and older was 649 mg. Women’s pattern of sodium intake by sandwich reporting status mirrored that of men, but was on a somewhat smaller scale, likely due to their lower overall food intake and lower percentage reporting sandwiches.
      Table 2Mean daily total intakes of energy and sodium by sandwich
      Sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File that were assigned food codes that fell into the WWEIA Food Category “Mixed Dishes—sandwiches (single code)”19 and/or consumed as part of a sandwich combination (indicated by a value of 5 for the “combination food type” variable12).
      reporting status, adults aged 20 years and older, What We Eat in America, National Health and Nutrition Examination Survey (WWEIA, NHANES) 2009-2010, 1 day
      Sample weights designed for dietary analysis were used to produce estimates representative of the US population for the years of collection.
      Sex and age (y)Energy (kcal)Sodium (mg)
      Sandwich ReportersSandwich NonreportersSandwich ReportersSandwich Nonreporters
      mean±standard error of the mean
      Men
      20-392,858±57.92,490±70.94,783±91.84,102±111.6
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      40-592,717±63.22,456±75.24,724±140.44,013±126.4
      60+2,203±38.91,926±38.4
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      3,817±75.23,338±92.0
       Total 20+2,653±36.52,347±48.0
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      4,541±51.53,892±72.1
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      Women
      20-392,025±34.71,764±39.1
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      3,305±56.32,973±104.5
      40-591,850±40.11,730±40.13,186±71.02,883±68.1
      60+1,684±43.41,580±32.22,900±88.92,613±44.6
       Total 20+1,875±19.61,701±23.0
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      3,157±33.22,841±46.8
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      All
      20-392,457±32.42,120±46.2
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      4,072±58.93,526±78.2
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      40-592,346±39.02,020±41.4
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      4,066±72.83,334±58.0
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      60+1,942±30.01,719±31.6
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      3,355±65.92,905±57.9
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
       Total 20+2,290±22.21,981±28.5
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      3,895±32.53,296±36.9
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      a Sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File that were assigned food codes that fell into the WWEIA Food Category “Mixed Dishes—sandwiches (single code)”

      USDA Food Surveys Research Group. Dietary methods research: Overview of the What We Eat in America Food Categories. http://www.ars.usda.gov/Services/docs.htm?docid=23429. Published July 8, 2013. Accessed September 10, 2013.

      and/or consumed as part of a sandwich combination (indicated by a value of 5 for the “combination food type” variable

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      ).
      b Sample weights designed for dietary analysis were used to produce estimates representative of the US population for the years of collection.
      Within sex and age, intake for sandwich nonreporters differs significantly from that of reporters (P<0.001).
      The unanticipated finding that sandwich consumption is associated with higher overall intake of energy underscores the importance of making healthful choices of sandwich ingredients. For both male and female sandwich reporters (especially men aged 20 to 59 years), mean energy intake exceeded the estimated calorie needs specified in DGA appendix 6 for people of that age who are sedentary,

      US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans 2010. 7th ed. Washington, DC: US Government Printing Office; 2010.

      the activity level applicable to most American adults based on accelerometer studies.
      • Troiano R.P.
      • Berrigan D.
      • Dodd K.W.
      • Masse L.C.
      • Tilert T.
      • McDowell M.
      Physical activity in the United States measured by accelerometer.
      • Tucker J.M.
      • Welk G.J.
      • Beyler N.K.
      Physical activity in US adults: Compliance with the Physical Activity Guidelines for Americans.
      Many sandwiches (such as burgers and franks) and common sandwich components (such as yeast breads, cheese, and cured meats) are among the top contributors not only to sodium,

      US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans 2010. 7th ed. Washington, DC: US Government Printing Office; 2010.

      • Hoy M.K.
      • Goldman J.D.
      • Murayi T.
      • Rhodes D.G.
      • Moshfegh A.J.
      Sodium Intake of the U.S. Population: What We Eat In America, NHANES 2007-2008.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.
      but also to energy

      US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans 2010. 7th ed. Washington, DC: US Government Printing Office; 2010.

      • O'Neil C.E.
      • Keast D.R.
      • Fulgoni V.L.
      • Nicklas T.A.
      Food sources of energy and nutrients among adults in the US: NHANES 2003-2006.
      in the diets of adult Americans. Reducing not only the sodium content but also the energy content of sandwiches would be beneficial.
      Comparisons of sodium density (mg sodium/1,000 kcal energy) between sandwich reporters and nonreporters are presented in Table 3. Regardless of sandwich reporting status, sodium density was approximately 1,700 to 1,800 mg per 1,000 kcal, suggesting that the higher sodium levels of sandwich reporters are explained by their higher energy intake. Other studies have found that sodium intake is positively correlated with energy intake.
      Institute of Medicine Committee on Strategies to Reduce Sodium Intake
      • Hoy M.K.
      • Goldman J.D.
      • Murayi T.
      • Rhodes D.G.
      • Moshfegh A.J.
      Sodium Intake of the U.S. Population: What We Eat In America, NHANES 2007-2008.
      This finding highlights the importance of current efforts to reduce sodium content of the food supply.
      Table 3Sodium density: Mean intake of sodium (mg) per 1,000 kcal energy intake, by sandwich
      Sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File that were assigned food codes that fell into the WWEIA Food Category “Mixed Dishes—sandwiches (single code)”19 and/or consumed as part of a sandwich combination (indicated by a value of 5 for the “combination food type” variable12).
      reporting status, adults aged 20 years and older, What We Eat in America, National Health and Nutrition Examination Survey (WWEIA, NHANES) 2009-2010, 1 day
      Sample weights designed for dietary analysis were used to produce estimates representative of the US population for the years of collection.
      Sex and age (y)Sodium Density (mg/1,000 kcal)P value
      A value of P<0.001 was considered statistically significant.
      Sandwich reportersSandwich nonreporters
      mean±standard error of the mean→
      Men
      20-391,728±28.11,679±32.20.249
      40-591,781±48.11,662±33.50.079
      60+1,763±34.21,750±38.50.838
       Total 20+1,757±16.51,689±24.40.018
      Women
      20-391,683±33.01,717±45.40.589
      40-591,775±24.31,723±49.20.308
      60+1,758±31.31,705±22.40.237
       Total 20+1,735±19.01,716±22.20.525
      All
      20-391,706±21.01,698±28.60.836
      40-591,779±25.01,698±37.10.131
      60+1,760±25.11,723±25.80.377
       Total 20+1,747±9.11,705±18.30.041
      a Sandwiches were defined as line items from the WWEIA, NHANES Individual Foods File that were assigned food codes that fell into the WWEIA Food Category “Mixed Dishes—sandwiches (single code)”

      USDA Food Surveys Research Group. Dietary methods research: Overview of the What We Eat in America Food Categories. http://www.ars.usda.gov/Services/docs.htm?docid=23429. Published July 8, 2013. Accessed September 10, 2013.

      and/or consumed as part of a sandwich combination (indicated by a value of 5 for the “combination food type” variable

      Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey: 2009-2010 Data Documentation, Codebook, and Frequencies: Dietary Interview - Individual Foods File - First Day (DR1IFF_F). http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/DR1IFF_F.htm. Published June 2012. Updated May 2013. Accessed September 10, 2013.

      ).
      b Sample weights designed for dietary analysis were used to produce estimates representative of the US population for the years of collection.
      c A value of P<0.001 was considered statistically significant.
      It has been shown that typical food choices exceed recommendations not only for sodium, but also for energy, fat, saturated fat, and empty calories.
      • Britten P.
      • Cleveland L.E.
      • Koegel K.L.
      • Kuczynski K.J.
      • Nickols-Richardson S.M.
      Impact of typical rather than nutrient-dense food choices in the US Department of Agriculture Food Patterns.
      However, Guenther and colleagues
      • Guenther P.M.
      • Lyon J.M.
      • Appel L.J.
      Modeling dietary patterns to assess sodium recommendations for nutrient adequacy.
      have demonstrated that it is possible to choose nutritionally adequate diets at recommended sodium levels, and registered dietitian nutritionists may find their description of how they selected lowest-sodium items useful when determining options for healthier, lower-sodium sandwiches. For example, in creating their “lower-sodium model,” they used no-salt-added foods when available, substituted cooked fresh meats for luncheon meats, and compared sodium levels on Nutrition Facts labels for similar products. Some other changes that could have a substantial positive effect on total dietary intake of sodium by American adults include incorporating foods lower in sodium and calories (such as vegetables) in sandwiches and reducing portion sizes.
      WWEIA, NHANES is a large, nationally representative sample, and 1 day of 24-hour dietary recall data may be used to describe the average daily intake of the US population. However, our study does have some limitations. First, underreporting is a recognized problem in self-reported dietary data. To address this issue, the AMPM used in collecting WWEIA data has undergone extensive methodologic testing to enhance food recall and minimize forgotten food items.
      • Raper N.
      • Perloff B.
      • Ingwersen L.
      • Steinfeldt L.
      • Anand J.
      An overview of USDA’s Dietary Intake Data System.
      It is unknown whether sandwiches or sandwich ingredients are underreported to a greater or lesser extent than other foods. Second, sodium intakes were based only on food and beverage (including water) intakes and do not include salt added at the table or sodium from dietary supplements or antacids. However, these sources account for a very small proportion of total sodium intake—6.2% from salting at the table
      • Mattes R.D.
      • Donnelly D.
      Relative contributions of dietary sodium sources.
      and 1% or less from supplements, even among supplement users.

      US Department of Agriculture, Agricultural Research Service. 2012. Table 37: Total nutrient intakes: Percent reporting and mean amounts of selected vitamins and minerals from food and dietary supplements, by gender and age, What We Eat in America, NHANES 2009-2010. http://www.ars.usda.gov/SP2UserFiles/Place/12355000/pdf/0910/Table_37_SUP_GEN_09.pdf. Accessed October 31, 2013.

      A third issue concerns how sandwiches were defined. Expanding or restricting what foods or combinations of foods are considered a sandwich would alter all the estimates reported here. For that reason, it is not appropriate to compare the sodium contribution of sandwiches as operationalized in this study to that reported in other studies that analyzed only single-code sandwiches and did not take sandwich combinations into account.
      Centers for Disease Control and Prevention
      Vital signs: Food categories contributing the most to sodium consumption—United States, 2007-2008.
      • Cotugna N.
      • Fanelli-Kuczmarski M.
      • Clymer J.
      • Hotchkiss L.
      • Zonderman A.B.
      • Evans M.K.
      Sodium intake of special populations in the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study.

      Conclusions

      Sandwiches contribute approximately one fifth of total sodium intake by American adults. For this population, sandwich consumption is associated with higher overall energy and sodium intakes, but not a higher overall sodium density of the diet. Due to the large percentage of individuals who consume sandwiches, registered dietitian nutritionists may find it fruitful to counsel clients on healthful sandwich choices along with attention to portion sizes.

      Acknowledgements

      The authors wish to thank Sharon J. Mickle for her early contributions to the design of this study.

      Supplementary Materials

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      Biography

      R. S. Sebastian is a nutritionist, US Department of Agriculture, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD.
      C. Wilkinson Enns is a nutritionist, US Department of Agriculture, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD.
      M. K. Hoy is a nutritionist, US Department of Agriculture, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD.
      J. D. Goldman is a mathematical statistician, US Department of Agriculture, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD.
      A. J. Moshfegh is a research leader, US Department of Agriculture, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD.