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Dietary Reference Intakes for Sodium and Potassium (2019)

Chapter: Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods

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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Appendix F

Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods

In accordance with methodologies established and used in previous Dietary Reference Intake (DRI) reports, the committee reviewed evidence on breast milk composition and complementary food intake to estimate the potassium and sodium Adequate Intakes (AIs) for infants 0–6 and 7–12 months of age. As many of the studies and analyses were similar for potassium and sodium, this appendix is organized by category of intake (i.e., estimating contributions of breast milk and complementary food) rather than by nutrient.

ESTIMATING THE POTASSIUM AND SODIUM CONTENT OF BREAST MILK

The committee first reviewed the evidence on the concentration of potassium and sodium in breast milk. These estimates were then used to establish the AIs for infants 0–6 months of age and were used in conjunction with estimates of potassium and sodium intake from complementary foods (described later in this appendix) to establish the AIs for infants 7–12 months of age. The committee’s process for estimating the potassium and sodium content of breast milk is described in the sections that follow.

Identifying Relevant Studies

The committee sought to identify studies that reported potassium and/or sodium concentrations in breast milk. Specifically, the committee focused on studies of mature breast milk from females with term infants conducted

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

in countries that have populations assumed to be similar to those in Canada and the United States. As breast milk composition has been evaluated and summarized by various groups and investigators, the committee elected to leverage these resources rather than conducting a de novo literature search. Accordingly, the committee identified relevant studies by reviewing citations in the Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2005 DRI Report) (IOM, 2005), the European Food Safety Authority (EFSA) Dietary Reference Values (DRVs) for potassium (EFSA, 2016), the January 2018 draft of the EFSA DRVs for sodium (EFSA, 2018), and a recent review article on breast milk composition (Wu et al., 2018).

Characteristics of the identified studies meeting the committee’s inclusion criteria are summarized in Tables F-1 and F-2 for potassium and sodium, respectively. Many of the identified studies provided repeated measurements of the concentrations over time among a cohort of women assessed at several time points (identified as longitudinal studies) or among different cohorts of women assessed at different time points (identified as cross-sectional studies). The concentration at each specific time point at which an assessment was made in each study was considered.

TABLE F-1 Mean Potassium Concentration in Mature Breast Milk from Women with Term Infantsa

Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Potassium Concentration, mg/L
0–6 Months 7–12 Months
Longitudinal Studies
Gross et al., 1980 (United States) Milk expressed manually or by mechanical emptying; analyzed by atomic emission spectrophotometry 11 Not indicated 28 days (11) 587 (27)*
Picciano et al., 1981 (United States) Milk expressed manually or by hand pump; atomic absorption spectrophotometry 26 Exclusivec 1 month (26)
2 moths (26)
3 moths (26)
466 (93)
427 (87)
407 (80)
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Potassium Concentration, mg/L
0–6 Months 7–12 Months
Lemons et al., 1982 (United States) Milk expressed using an electric pump; flame emission spectrophotometry 7 Not indicated 21 days (7)
28 days (7)
545 (21)*
508 (20)*
Dewey and Lonnerdal, 1983 (United States) Manual milk expression at second feeding; flame atomic absorption spectrophotometer, emission mode 20 19 exclusived 19 exclusive 16 exclusive 13 exclusive 11 exclusive 11 exclusive 1 month (13)
2 months (16)
3 moths (18)
4 months (16)
5 months (14)
6 months (15)
527 (70)
477 (79)
470 (81)
464 (89)
460 (85)
430 (63)
Dewey et al., 1984 (United States) Milk expressed manually or using a manual pump at second feeding; flame atomic absorption spectrophotometer using emission mode 15 Mothers were producing ≥ 500 mL/d 4–6 months
(15 women, 38 samples)
443 (71)
7–11 months
(8 women, 26 samples)
389 (41)
Morriss et al., 1986 (United States) Milk expressed using a breast pump; flame photometry 52 Not indicated 14–21 days
(10 samples)
669 (23)*
120–180 days
(10 samples)
500 (19)*
Allen et al., 1991 (United States) Milk expressed manually; ion-selective electrodes verified by flame emission photometry 13 Exclusive 21 days (13)
45 days (13)
90 days (13)
180 days (10)
633 (18)*
590 (16)*
543 (16)*
485 (16)*
Holt, 1993 (United Kingdom) Manual expression; flame photometry 4 Not indicated 5–16 weeks
(28 samples)
594 (86)
Motil et al., 1997 (United States) Milk expressed by manual or mechanical pumping; atomic absorption spectroscopy 11e Exclusive Exclusive Partial Partial 6 weeks (11)
12 weeks (11)
18 weeks (11)
24 weeks (11)
545 (43)
524 (69)
494 (73)
498 (67)
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Potassium Concentration, mg/L
0–6 Months 7–12 Months
Wack et al., 1997 (United States)f Manual expression or breast pump; inductively coupled plasma-atomic emission spectrometry 30 Not indicated 14–60 days (27) 585 (124)
61–120 days (20) 490 (85)
121–180 days (25) 485 (66)
181–240 days (29) 473 (63)
241–300 days (17) 470 (72)
301–360 days (14) 445 (53)
Bauer and Gerss, 2011 (Germany) Milk expressed using an electric pump; absorption spectrometer and colorimetric assay 10 Not indicated 0–8 weeks (10) 450g (74)
Perrin et al., 2017 (United States) Spectroscopy 16 Not indicated 11 months (16)
12 months (16)
370 (51)
380 (69)
Cross-Sectional Studies
Keenan et al., 1982 (United States) Milk expressed using an electric pump; flame photometry 28 Not indicated 3.5–6 weeks (14) 594 (70)
8.5–18 weeks (14) 540 (51)
20–32 weeks (12) 520 (43)
Fly et al., 1998 (United States) Milk expressed using an electric breast pump; inductively coupled plasma atomic emission spectroscopy 14 Not indicated 2–8 months
At rest (14)
After exercise (14)
461 (24)*
447 (16)*
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Potassium Concentration, mg/L
0–6 Months 7–12 Months
Bjorklund et al., 2012 (Sweden) Manual breast pump and/or a passive breast milk sampler; inductively coupled plasma mass spectrometry 60 Not indicated 2–3 weeks (60) 633h (40)
Parr et al., 1991i (Hungary) Milk expressed using a breast pump; atomic absorption spectrophotometry 71† Partial 3 months (71†) 554‡ (9)
Parr et al., 1991i (Sweden) Milk expressed using a breast pump; atomic absorption spectrophotometry 29† Partial 3 months (29†) 548‡ (19)

NOTES: Breast milk potassium concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 39.1. Unless otherwise noted, concentrations are presented as mean (standard deviation). * = standard error; † = number of observations; ‡ = median; cross-sectional = different women at each time point; longitudinal = same women at each time point; mg/L = milligrams per liter.

aMature human milk is defined as ≥ 21 days postpartum. Only data on milk for full-term (> 37 weeks) infants are included.

bNumber of women in the sample.

cAll infants were exclusively breastfed, except for one infant at 2 and 3 months postpartum and one other infant at 3 months postpartum.

dExclusive breastfeeding was defined as ≤ 50 kcal from other sources.

eValues are for adults. Publication also has values for adolescents 16.5 ± 0.6 years of age, but they are not presented here.

fThere is a discrepancy in this study about the time period of milk collection. The text states that milk samples were obtained starting at 2 weeks postpartum; however, their data table gives a time period of 0–60 days postpartum.

gValues are the average of the first 8 weeks postpartum.

hBased on collection of milk from each mother during 7 days of sampling.

iValues for Guatemala, Nigeria, the Philippines, and Zaire were also presented in the publication, but they are not presented here.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

TABLE F-2 Mean Sodium Concentration in Mature Breast Milk from Women with Term Infantsa

Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Sodium Concentration, mg/L
0–6 Months 7–12 Months
Longitudinal Studies
Gross et al., 1980 (United States) Milk expressed manually or by mechanical emptying; atomic emission spectrophotometry 11 Not indicated 28 days (11) 195 (41)*
Picciano et al., 1981 (United States) Milk expressed manually or by hand pump; atomic absorption spectrophotometry 26 Exclusivec 1 month (26) 151 (55)
2 month (26) 121 (50)
3 month (26) 126 (47)
Lemons et al., 1982 (United States) Milk expressed using an electric pump; flame emission spectrophotometry 7 Not indicated 21 days (7) 157 (23)*
28 days (7) 162 (22)*
Dewey and Lonnerdal, 1983 (United States) Manual milk expression at second feeding; flame atomic absorption spectrophotometer using emission mode 20 19 exclusived 1 month (13) 227 (152)
19 exclusive 2 months (16) 264 (223)
16 exclusive 3 months (18) 184 (139)
13 exclusive 4 months (16) 175 (138)
11 exclusive 5 months (14) 166 (130)
11 exclusive 6 months (15) 134 (78)
Garza et al., 1983 (United States) Milk expressed using a breast pump; atomic absorption spectrophotometry 6 Exclusive at 24 weeks; Partial at all other weeks 24 weeks (5)e 136 (16)*
26 weeks (6) 119 (7)*
28 weeks (5) 123 (8)*
30 weeks (6) 121 (6)*
32 weeks (5) 168 (23)*
34 weeks (6) 203 (19)*
36 weeks (5) 297 (57)*
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Sodium Concentration, mg/L
0–6 Months 7–12 Months
Butte et al., 1984 (United States) Milk expressed using a breast pump; atomic absorption spectrometry 13 The majority were exclusively breastfed 4 weeks (13) 184 (54)
6 weeks (13) 173 (65)
8 weeks (13) 153 (47)
10 weeks (13) 150 (49)
12 weeks (13) 130 (41)
Dewey et al., 1984 (United States) Milk expressed manually or using a manual pump at second feeding; flame atomic absorption spectrophotometer using emission mode 15 Mothers were producing ≥ 500 mL/d 4–6 months (15 women, 36 samples) 113 (69)
7–11 months (8 women, 26 samples) 84 (42)
Morriss et al., 1986 (United States) Milk expressed using a breast pump; flame photometry 52 Not indicated 14–21 days (10 samples) 168 (12)*
120–180 days (10 samples) 110 (23)*
Allen et al., 1991 (United States) Milk expressed manually; ion-selective electrodes verified by flame emission photometry 13 Exclusive 21 days (13) 212 (9)*
45 days (13) 165 (9)*
90 days (13) 145 (9)*
180 days (10) 138 (9)*
Holt, 1993 (United Kingdom) Manual expression; flame photometry 4 Not indicated 5–16 weeks (28 samples) 107 (29)
Motil et al., 1997 (United States) Milk expressed by manual or mechanical pumping; atomic absorptiometry 11f Exclusive 6 weeks (11) 94 (27)
Exclusive 12 weeks (11) 71 (23)
Partial 18 weeks (11) 70 (16)
Partial 24 weeks (11) 75 (23)
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Sodium Concentration, mg/L
0–6 Months 7–12 Months
Wack et al., 1997 (United States)g Manual expression or breast pump; inductively coupled plasma atomic emission spectrometry 30 Not indicated 14–60 days (27) 182 (83)
61–120 days (20) 129 (61)
121–180 days (25) 136 (76)
181–240 days (29) 139 (142)
241–300 days (17) 124 (65)
301–360 days (14) 122 (123)
Bauer and Gerss, 2011 (Germany) Milk expressed using an electric pump; absorption spectrometer and colorimetric assay 10 Not indicated 0–8 weeks (10) 258h (48)
Perrin et al., 2017 (United States) Spectroscopy 19 Not indicated 11 months (16) 12 months (16) 70 (19) 70 (24)
Cross-Sectional Studies
Keenan et al., 1982 (United States) Milk expressed using an electric pump; flame photometry 28 Not indicated 3.5–6 weeks (14) 182 (69)
8.5–18 weeks (14) 108 (46)
20–32 weeks (12) 124 (30)
Koo and Gupta, 1982 (Australia) Manual milk expression; flame photometer 45 Not indicated 15–28 days (48 samples) 159 (5)*
Fly et al., 1998 (United States) Milk expressed using an electric breast pump; inductively coupled plasma atomic emission spectroscopy 14 Not indicated 2–8 months
At rest (14) 115 (11)*
After exercise (14) 109 (5)*
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Reference (Country) Methodology Nb Breastfeeding Status Stage of Lactation, Duration Postpartum (N) Mean Sodium Concentration, mg/L
0–6 Months 7–12 Months
Bjorklund et al., 2012 (Sweden) Manual breast pump and/or a passive breast milk sampler; inductively coupled plasma mass spectroscopy 60 Not indicated 2–3 weeks (60) 217i (77)
Parr et al., 1991j(Hungary) Milk expressed using a breast pump; atomic absorption spectrophotometry 71† Partial 3 months (7†) 105‡ (6)
Parr et al., 1991j (Sweden) Milk expressed using a breast pump; atomic absorption spectrophotometry 29† Partial 3 months (29†) 88‡ (17)

NOTES: Breast milk sodium concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 23.0. Unless otherwise noted, concentrations are presented as mean (standard deviation). * = standard error; † = number of observations; ‡ = median; longitudinal = same women at each time point; cross-sectional = different women at each time point.

aMature human milk is defined as ≥ 21 days postpartum. Only data on milk for full-term (> 37 weeks) infants are included.

bNumber of women in the sample.

cAll infants were exclusively breastfed, except for one infant at 2 and 3 months postpartum and one other infant at 3 months postpartum.

dExclusive breastfeeding was defined as ≤ 50 kcal from other sources.

eMilk was collected before weaning began (24 weeks postpartum) and at 2 week intervals for 12 weeks.

fValues are for adults. Publication also has values for adolescents aged 16.5 ± 0.6 years, but they are not presented here.

gThere is a discrepancy in this study about the time period of milk collection. The text states that milk samples were obtained starting at 2 weeks postpartum; however, their data table gives a time period of 0–60 days postpartum.

hValues are the average of the first 8 weeks postpartum.

iBased on collection of milk from each mother during 7 days of sampling.

jValues for Guatemala, Nigeria, the Philippines, and Zaire were also presented in the publication, but they are not presented here.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

Synthesizing the Evidence Across Studies to Estimate Breast Milk Composition

The committee conducted meta-analyses to estimate potassium and sodium concentrations of breast milk. Because many of the studies measured the potassium and/or sodium breast milk concentrations at several time points across the two intervals of interest (0–6 months and 7–12 months), a meta-analysis of these measurements faced two obstacles that needed to be taken into consideration in order to make full use of the available data: (1) the correlation between observations at successive time points and (2) the trend in the measures over time.

In a setting in which not all the data are used, an exemplar for each study is taken, being the measure closest to the midpoint of the time interval of interest (3 months for the 0–6-month time interval; and 9 months for the 7–12-month interval). These midpoint meta-analyses are presented in Figures F-1 and F-2 for the mean potassium concentration in the time intervals of 0–6 months and 7–12 months, respectively. The rounded mean potassium concentration is 515 mg/L for the 0–6-month interval and 435 mg/L for the 7–12-month interval. For context, both the 2005 DRI Report and EFSA approximated the potassium concentration of mature breast milk to be 500 mg/L (EFSA, 2016; IOM, 2005); the U.S. Department of Agriculture (USDA) National Nutrient Database for Standard Reference estimates potassium concentration of mature breast milk to be 523 mg/L (USDA/ARS, 2018). The mean sodium concentration in the time interval 0–6 months and 7–12 months are presented in Figures F-3 and F-4, respectively. The rounded mean sodium concentration is 140 mg/L for the 0–6-month interval and 110 mg/L for the 7–12-month interval. For context, the 2005 DRI Report estimated the sodium concentrations of breast milk to be 160 and 130 mg/L for 0–6 and 7–12 months postpartum, respectively (IOM, 2005). The EFSA draft DRVs for sodium approximated the sodium concentration of mature breast milk to be 150 mg/L (EFSA, 2018). The USDA National Nutrient Database for Standard Reference provides an estimate of the sodium concentration of mature breast milk of 174 mg/L (USDA/ARS, 2018). The I2 is large, indicating a high degree of heterogeneity of the results across the studies.1 There are opinions that I2 for a meta-analysis for the type of analysis considered here needs to be considered from a different perspective (Mills et al., 2015), that is, when the focus of the meta-analysis is not to combine the effect measures (for instance, when two interventions are compared), but rather to combine a characteristic of a population of interest, such as the prevalence of an event or, as in this case, the mean of a concentration.

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1 The I2 statistic is a test of heterogeneity.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Image
FIGURE F-1 Mean potassium concentration (mg/L) in mature breast milk from women with term infants: 0–6 months.
NOTES: Breast milk potassium concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 39.1. CI = confidence interval; SE = standard error.
Image
FIGURE F-2 Mean potassium concentration (mg/L) in mature breast milk from women with term infants: 7–12 months.
NOTES: Breast milk potassium concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 39.1. CI = confidence interval; SE = standard error.
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×
Image
FIGURE F-3 Mean sodium concentration (mg/L) in mature breast milk from women with term infants: 0–6 months.
NOTES: Breast milk sodium concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 23.0. CI = confidence interval; SE = standard error.
Image
FIGURE F-4 Mean sodium concentration (mg/L) in mature human milk from women with term infants: 7–12 months.
NOTES: Breast milk sodium concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 23.0. CI = confidence interval; SE = standard error.
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

The committee conducted additional supporting meta-analyses in which the correlations and trends in the measures were not considered. First, in the study-specific analysis, a meta-analysis was conducted on the measures within a study in order to get a single measure for the study. These results for each study were then meta-analyzed to derive an overall concentration estimate. Four analysis scenarios were considered depending on the studies included (1) all studies, (2) only longitudinal studies, (3) only cross-sectional studies, and (4) all studies in which the individual participants were the unit of analysis.2 These results are provided in Table F-3, and all yield concentration levels that were derived using the midpoint analysis. Second, in the time-specific analysis, a meta-analysis was conducted on the measures for a specific month across the studies in order to get a single measure for that month. The results for each month were then meta-analyzed to derive an overall concentration. Again, the four analysis scenarios described above were considered. These results are provided in Table F-3, and all yield concentration levels that were derived using the midpoint analysis. Methods have been identified that attempt to take the correlation between observations at successive time points and/or the trend in the measures over time (Peters and Mengersen, 2008). The Bayesian approach has been reviewed and is expected to yield similar results as those found for the midpoint analysis. In total, the additional meta-analyses support the concentrations of potassium and sodium in breast milk that the committee selected.

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2 Excludes two studies in which the breast milk samples were unit of analysis.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

TABLE F-3 Potassium and Sodium Concentrations in Mature Breast Milk from Women with Term Infant, Estimated Using Various Meta-Analysis Scenarios

Meta-Analysis Scenario Estimated Potassium Concentration, mg/L Estimated Sodium Concentration, mg/L
0–6 Months 7–12 Months 0–6 Months 7–12 Months
Study Specific
All studies included 526 [483, 568] 436 [375, 496] 145 [125, 166] 109 [79, 139]
Only longitudinal studies 511 [474, 547] 409 [355, 462] 149 [123, 174] 105 [72, 139]
Only cross-sectional studies 552 [470, 634] 519 [495, 543] 138 [101, 175] 124 [107, 141]
Only studies in which the participants were unit of analysis 518 [473, 564] 436 [375, 496] 148 [125, 171] 109 [79, 139]
Time Specific
All studies included 504 [471, 536] 428 [365, 491] 139 [109, 169] 107 [74, 140]
Only longitudinal studies 489 [465, 514] 424 [366, 481] 144 [116, 172] 107 [74, 140]
Only cross-sectional 555 [479, 632] 519 [495, 543] 131 [104, 158] 124 [107, 141]
Only studies in which the participants were unit of analysis 497 [468, 526] 428 [365, 491] 140 [111, 169] 107 [74, 140]

NOTES: Values are presented as mean [95% confidence interval]. Breast milk concentrations are presented as mg/L. To convert the mg/L value to mmol/L, divide the concentration by 39.1 for potassium and 23.0 for sodium.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

ESTIMATING POTASSIUM AND SODIUM INTAKE FROM COMPLEMENTARY FOODS

The committee reviewed evidence on potassium and sodium intake from complementary foods among infants 7–12 months of age and estimated intakes from three analyses that are briefly described below3:

  • Tian et al. (2013) assessed potassium and sodium intake among infant and preschool-aged National Health and Nutrition Examination Survey (NHANES) 2003–2010 participants. The analysis provided estimates of usual total intake and estimates of intake from complementary foods among infants 7–11 months of age, stratified by breastfeeding status. Complementary foods were defined as any food or beverages other than breast milk, infant formula, or other milks (e.g., cow’s milk). Breastfeeding status was classified based on whether the infant had reportedly consumed breast milk, as documented in the 24-hour dietary recalls. The committee considered the estimates, as provided in the publication.
  • Maalouf et al. (2015) assessed the top sources of sodium intake among NHANES 2003–2010 participants from birth to 24 months of age. The analysis was not stratified by breastfeeding status. Breast milk, infant formula, and milk were among the top food categories contributing to sodium intake among infants 6–11.9 months of age. The proportion of total sodium intake that came from each of these food categories, along with the total sodium intake among this age group, were reported. The committee used this information to estimate the amount of sodium intake that came from complementary foods (i.e., sources other than breast milk, infant formula, and milk).
  • The committee was provided with results from an analysis that assessed the sources of potassium and sodium intake among Feeding Infants and Toddlers Study (FITS) 2016 participants. The provided analysis did not stratify by breastfeeding status. The committee used the estimates of total potassium and sodium intake and subtracted the estimated contributions from breast milk, infant formula, and other milks to estimate the contributions from complementary foods.

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3 The brief summaries included herein only describe the portion of the analyses applicable to the committee’s estimation of potassium and sodium intake from complementary foods for infants 7–12 months of age.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

The estimates of potassium and sodium intakes from complementary foods are presented in Tables F-4 and F-5, respectively. Based on these analyses, the committee estimated that complementary foods contributed approximately 600 mg/d potassium and 300 mg/d sodium for infants 7–12 months of age. These estimates were used in combination with estimates of intake from breast milk to establish the AIs for potassium and sodium for infants 7–12 months of age.

TABLE F-4 Estimates of Potassium Intake from Complementary Foods, Infants 7–12 Months of Age

Data Source Age Range, Months Breastfeeding Status of Infants Potassium Intake from Complementary Food, mg/daya
NHANES 2003–2010 7–11 Not BF 633 ± 21
7–11 BFb 546 ± 34
FITS 2016 6–11.9 All 594 ± 27c

NOTES: Intake values are presented in milligrams. To convert the milligram value to mmol, divide the intake value by 39.1. BF = stratified analysis of infants who consumed breast milk; FITS = Feeding Infants and Toddlers Study; NHANES = National Health and Nutrition Examination Survey; Not BF = stratified analysis of infants who did not consume breast milk.

aMean ± standard error.

bConsumption of at least some breast milk, as reported on the 24-hour dietary recall.

cValue from subtraction, approximate standard error.

SOURCES: FITS 2016 (unpublished); Tian et al., 2013.

TABLE F-5 Estimates of Sodium Intake from Complementary Foods, Infants 7–12 Months of Age

Data Source Age Range, Months Breastfeeding Status of Infants Sodium Intake from Complementary Food, mg/daya
NHANES 2003–2010 7–11 Not BF 337 ± 27
7–11 BFb 267 ± 36
6–11.9 All 341 ± 31c
FITS 2016 6–11.9 All 294 ± 23c

NOTES: Intake values are presented in milligrams. To convert the milligram value to mmol, divide the intake value by 23.0. BF = stratified analysis of infants who consumed breast milk; FITS = Feeding Infants and Toddlers Study; NHANES = National Health and Nutrition Examination Survey; Not BF = stratified analysis of infants who did not consume breast milk.

aMean ± standard error.

bConsumption of at least some breast milk.

cValue from subtraction, approximate standard error.

SOURCES: FITS 2016 (unpublished); Maalouf et al., 2015; Tian et al., 2013.

Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
×

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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Page 534
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Page 536
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Page 537
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Page 538
Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Suggested Citation:"Appendix F: Estimates of Potassium and Sodium Intakes from Breast Milk and Complementary Foods." National Academies of Sciences, Engineering, and Medicine. 2019. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. doi: 10.17226/25353.
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Next: Appendix G: Sources of Evidence for Potassium and Sodium Intake Distributions »
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As essential nutrients, sodium and potassium contribute to the fundamentals of physiology and pathology of human health and disease. In clinical settings, these are two important blood electrolytes, are frequently measured and influence care decisions. Yet, blood electrolyte concentrations are usually not influenced by dietary intake, as kidney and hormone systems carefully regulate blood values.

Over the years, increasing evidence suggests that sodium and potassium intake patterns of children and adults influence long-term population health mostly through complex relationships among dietary intake, blood pressure and cardiovascular health. The public health importance of understanding these relationships, based upon the best available evidence and establishing recommendations to support the development of population clinical practice guidelines and medical care of patients is clear.

This report reviews evidence on the relationship between sodium and potassium intakes and indicators of adequacy, toxicity, and chronic disease. It updates the Dietary Reference Intakes (DRIs) using an expanded DRI model that includes consideration of chronic disease endpoints, and outlines research gaps to address the uncertainties identified in the process of deriving the reference values and evaluating public health implications.

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