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Sodium, potassium, calcium, phosphorus, and magnesium in foods from the United States total diet study
JOURNAL
OF FOOD
COMPOSITION
AND ANALYSIS
3, 145- 165 (1990)
Sodium, Potassium, Calcium, Phosphorus, and Magnesium in Foods from the United States Total Diet Study J.A.T.PENNINGTON*" Food
and Drug Administration, *Division and tKansas City District Q&e, Received
March
AND B.
YOUNG?
qf Nutrition, Wushington, D.C. 20204. Kansas City, Missouri 64106, U.S.A.
6, 1990, and in revised
form
August
U.S.A.;
10, 1990
Data on the concentrations of sodium, potassium, calcium, phosphorus, and magnesium in the 234 foods of the United States Total Diet Study from 1982 to 1989 are summarized per 100 g and per typical serving portion. Per serving, mixed dishes and soups were higher in sodium; mixed dishes, root/tuber vegetables, and dairy products were higher in potassium; dairy products were higher in calcium; dairy products, mixed dishes, and animal flesh were higher in phosphorus; and nuts, mixed dishes, and legumes were higher in magnesium. Of the top 20 foods highest in each element per serving, the coefficients of variation averaged 20% (range IO-48%) for sodium, 15% (range 2-47%) for potassium, 21% (range 12-24%) for calcium, 14% (range 7-22%) for phosphorus, and 17% (range 7-24%) for magnesium. Nutrient variation reflects genetic, environmental, processing, and analytic factors. Sodium variability most likely reflects the variable amount of salt added to foods and recipe ingredients by industry. o 1990 Academic press, hc.
INTRODUCTION
The United States Total Diet Study is a yearly program which monitors the levels of contaminants and nutrients in the food supply and diets of selected age-sex groups (Pennington and Gunderson, 1987). The food list and diets are periodically revised when new information from national food consumption surveys becomes available. The current program (based on the 1982 revision) includes the collection and analyses of 234 core foods four times per year (Pennington, 1982, 1983). The nutritional evaluation of these foods includes analyses for 11 mineral elements: the macroelements sodium, potassium, calcium, phosphorus, and magnesium; and the microelements iron, zinc, copper, manganese, selenium, and iodine. Previous papers have presented the intakes of these elements for eight age-sex groups from 1982 to 1984 (Pennington et al., 1986), from 1982 to 1986 (Pennington et al., 1989), and from 1982 to 1989 (Pennington and Young, 1990). This paper presents the concentrations of the macroelements in the Total Diet Study foods and food groups from 1982 to 1989; the following paper presents results for the microelements. METHODS
AND
MATERIALS
The Total Diet Study foods are collected approximately four times per year, once from each of the four geographic regions of the United States (east, central, west, and south). The collection within a geographical area consists of the purchase of 246 foods and ingredients from each of three cities. The foods are purchased from supermarkets ’ To whom
correspondence
should
be addressed.
145
0889-1575/90
$3.00
Copyright 0 1990 by Academic Press, Inc. All rights of reproduction in any form reserved.
146
PENNINGTON
AND TABLE
TOTAL
DIET
STUDY
YOUNG
I
COLLECTION
LOCATIONS
Location
Date
April
1982
July
Buffalo,
1982
November February
June
CT;
CA; Phoenix,
Green
1983
Norfolk,
VA; Atlanta,
Boston,
MA; New York,
1983 1983
December
1983-
January
1984
March-April
Bay,
Honolulu, Topeka,
WI;
AZ;
1982
September
June-July
1984
September-
Chicago,
Newark,
Salt
NJ
Lake
IL;
City,
Detroit,
UT
MI
GA; Jacksonville,
FL
NY; Montgomwyville,
HI;
San Diego,
KS; St.
Louis,
1984 Beaumont/Port Juan,
October
NY; Hartford,
Fresno,
CA; Portland, MO; Dayton,
Arthur/Orange,
TX;
PA OR
OH
Nashville,
TN;
San
PR
Lancaster,
PA;
Tacoma,
Nassau-Suffolk,
WA; Bakersfield,
NY; Rochester,
CA; Salt
Lake
NY
City,
UT
1984
January-February
St.
Cloud,
MN; Rockford,
IL;
Flint,
MI
1985 April July
1985 1985
October-November 1985 January April
Dallas/Ft.
Worth,
Portland,
ME; Long
Los
Angeles/Long
Falls, 1986 1986
Macon,
GA; Charleston,
BeachlAsbury
Beach,
Park,
CA; Sacramento,
NJ;
WV New York,
NY
CA; Sioux
SD
Chattanooga, Cleveland, Wichita,
TX;
TN;
Ft.
Smith,
OH; Davenport,
AR; IA/Reek
Miami,
FL
Island-Moline,
IL;
KS
and fast-food chains within each city. The cities selected for inclusion in the program represent standard metropolitan statistical areas and are within commuting distance of a Food and Drug Administration (FDA) field office. Table 1 indicates the locations of the collections for the Total Diet Study program from 1982 to 1989. The same foods were purchased from the three cities over a 4week period. The foods from each weekly purchase were sent by air freight (packed in dry ice where necessary) to the Total Diet Laboratory in the FDA Kansas City District Office. Upon arrival in Kansas City the foods were logged in and checked to be sure the appropriate items were collected in requested quantities. If discrepancies were noted or if foods were damaged, the field office responsible for the delivery was asked to repeat the collection of the needed foods.
MACROELEMENTS
IN
TOTAL
July
STUDY
147
FOODS
l-Continued
TABLE
Date
DIET
Location
1986
Spokane,
WA; Albuquerque,
October
1986
Providence,
Januarg
1987
Memphis,
April-May
1987
RI; TN;
NM; Denver,
Albany,
Omaha,
NE; Fargo,
Brownsville/Harlingen/San Baton
July-Auqust
Rouge,
Portland,
CO
NY; Pittsburgh,
PA
ND
Benito,
TX;
Birmingham,
AL;
LA
OR; Fresno,
CA; Phoeniz,
AZ
1987 October
1987
Peoria,
January
1988
Baltimore,
March-April
El
IL;
Paso,
Indianapolis,
IN;
MD; Charleston, TX;
Pueblo,
Milwaukee,
SC; Tallahassee,
CO; Reno,
WI FL
NV
1988
June-July August November January
1988
Syracuse,
1988 1988
NY; New York
Ponce,
PR; Jackson,
Akron,
OH; Battle
Nassau/Suffolk,
1989
Passaic,
(Berqen
Co.,
MS; Columbus, Creek,
MI;
NJ);
Lincoln,
NY; Washington,
Manchester,
NH
GA
DC;
NE Patterson/Clifton/
NJ
Foods that required preparation or that were ingredients for mixed dishes were sent to a contract kitchen in close proximity to the Kansas City Laboratory. At the contract kitchen the foods were rinsed, cooked, and/or otherwise prepared for TABLE
2
LIMITSOFQUANTITATION (L,)FoR SODIUM,POTASSIUM,CALCIUM, PHOSPHORUS,AND MAGNESIUM FORTOTALDIETSTUDY FOODS
Element
Lq (mg/lOO
Na
0.20
K
0.50
Ca
0.20
P
0.050
Mg
0.10
gl
148
PENNINGTON
AND TABLE
QUALITY
CONTROL
EVALUATION
YOUNG
3 OF TOTAL
DIET
Spiked Percent
a NIST Standard
STUDY
DATA
SRMa
recovery
+ SD (n)
Percent
recovery
+ SD (n)
100.4
c
7.0
(456)
89.3
+ 6.3
(222)
100.8
t
7.8
(456)
91.7
+ 7.6
(226)
96.8
+ 11.7
(435)
96.4
+ 8.6
(216)
98.0
+
7.8
(437)
83.7
+ 5.6
(216)
97.8
-+
8.0
(456)
97.7
+ 6.6
(223)
Reference
Material
oyster
tissue.
consumption. The water used for rinsing and cooking procedures was deionized. Noniodized salt was added to mixed dishes as specified by recipe and to several other foods as indicated by package instructions, but other foods (e.g., meats and vegetables) were not salted. The prepared foods were then returned to the laboratory. The similar foods from the three cities were cornposited. Each of the 234 foods for a single collection represented an equal weight composite from the three cities of the geographical area. Aliquots of each of the 234 composite foods were then analyzed for nutritional elements. The five macroelements were determined by inductively coupled plasma atomic emission spectrometry (Marts and Meloan, 1982). Twenty-eight test portions of each food were analyzed for sodium, potassium, and magnesium. For calcium and phosphorus, which were not determined in the first collection, there were 27 analyses. In total, there were 32,393 analyses. The foods were analyzed in series with 15-30 test portions per series. For each element being determined, the series analysis included two reagent blanks, duplicate analysis of at least one test portion, at least one spiked recovery analysis, and at least one standard reference material (SRM) from the National Institute of Standards and Technology (NET). The limits of quantitation for the analytical methodology (Table 2) were based on repetitive analyses of blank solutions (Keith et al., 1983). Values below the limits of quantitation were reported as zeros. Values for sodium, potassium, calcium, and phosphorus were rounded to the nearest whole number; values for magnesium were carried to one decimal point. The data were evaluated for outliers by means of the Grubbs extreme deviation test (Grubbs, 1969). Median and mean (plus or minus standard deviation) concentrations of the five elements in the 234 foods were determined per 100 g and per typical serving portion. The concentrations of the elements by food
MACROELEMENTS
IN
TOTAL TABLE
DIET
STUDY
149
FOODS
4
SODIUM,POTASSIUM,CALCIUM,PHOSPHORUS,ANDMAGNESIUMCONTENTOFTOTAL FOODSIN~~PER IOOg" rood YBlW" scdim PotaIll"m CDlCIL.m PhoM!or"r
DIETSTUDY q all”EIIM
150
PENNINGTON TABLE
AND
YOUNG
4-Continued
MACROELEMENTS
IN TABLE
TOTAL
DIET
STUDY
FOODS
151
&-Continued
groups per serving portion were determined. Coefficients of variation (CVs) were calculated for foods highest in each element per serving to assessthe variability of the elements.
152
PENNINGTON TABLE
laod
Yale?”
Pcdlrn
POIBEII”m
AND
YOUNG
4-Continued CalclM
RESULTS
Results of the quality control measures are shown in Table 3. There were 12-20 spiked recoveries per collection. Average spiked recoveries ranged from 96.8 to 100.8%, and recoveries for SRMs ranged from 83.7 to 97.7%.
154
PENNINGTON TABLE
AND 4-Continued
YOUNG
MACROELEMENTS
IN
TOTAL
DIET
STUDY
FOODS
155
An evaluation for outliers resulted in the omission of two sets of results (one of pancake syrup and one of chocolate powder for milk) and the omission of 10 values for sodium and two values for potassium. Thus, of 32,393 analyses, results for 22 (0.07%) were identified as outliers. The medians and means with standard deviations for the macroelements in the 234 Total Diet Study foods are presented in Table 4 per 100 g and in Table 5 per typical serving portions of table-ready, edible food. Table 6 presents the average levels of the elements per serving by food group. By food groups, the major sources of the macroelements are mixed dishes and soups for sodium; mixed dishes, root/tuber vegetables, and dairy products for potassium; dairy products for calcium; dairy products, mixed dishes, and animal flesh for phosphorus; and nuts, mixed dishes, and legumes for magnesium. Of the seven strained/ junior food groups, dessert and dinners were highest in sodium, vegetables were highest in potassium, dessert and vegetables were highest in calcium, meat/poultry were highest in phosphorus, and vegetables were highest in magnesium. The 20 foods (excluding strained/junior foods) highest in sodium (575-1730 mg/ serving) included 11 mixed dishes, cured ham, four soups, cottage cheese, sauerkraut, tomato sauce, and dill pickles. These were all products to which salt had been added by industry or by homemade recipe. Some of the recipe ingredients also contained salt added by industry (e.g., tomato paste in the homemade lasagna). The CVs for the sodium content of these products averaged 20% and ranged from 10 to 48%; the higher CVs were for vegetable beef soup (CV = 35%) and homemade beef and vegetable stew (CV = 48%). The variability of sodium in these products is most likely due to the variable amounts of salt added by industry. The 20 foods highest in potassium (393-790 mg/serving) included five mixed dishes, chocolate milkshake, seven vegetables, three fruits, three dairy items, and tomato soup. CVs for these products averaged 15% and ranged from 2% for avocados to 47% for cantaloupe. The 20 foods highest in calcium (127-350 mg/serving) included 11 dairy products, three dairy desserts, three mixed dishes, collards, pancakes, and tomato soup. CVs averaged 21% and ranged from 11 to 38% with the higher CVs for vanilla ice milk (CV = 34%) chicken noodle casserole (CV = 36%) and tomato soup (CV = 38%). The variability of calcium in some products may reflect recipe formulations (i.e., the amounts of milk, cheese, or cream in these products).
156
PENNINGTON
AND TABLE
YOUNG
5
SODIUM,POTASSIUM,CALCIUM,PHOSPHORUS,ANDMAGNESIUM CONTENTOFTOTALDIETSTUDY FOODSIN~~PERSERVING'
MACROELEMENTS
IN
TOTAL
TABLE Food r.rvimb
Yeighrof *cd,uI rervins (‘I, Hfdian*earpAm
P.tasIIm *f-San lean*sdw
DIET
STUDY
FOODS
157
S-Continued ca,cim *cd,an*eMt-sdm
Phorphcmn edin *earerdm
-iul “edianlleac-rdm
PENNINGTON TABLE
Pm.SSI”n
AND
YOUNG
5-Continued Calclm
The 20 foods highest in phosphorus (209-4 15 mg/serving) included six mixed dishes, three animal flesh items, seven dairy products, two dairy desserts, pancakes, and raisin bran cereal. CVs averaged 14% and ranged from 7% for evaporated canned milk to 22% for frozen, fried chicken dinner. The 20 foods highest in magnesium (37.5-83. I mg/serving) included two ready-to-
eat cereals, six mixed dishes, eight vegetables (spinach and legumes), two nuts, chocolate milkshake, and fried shrimp. CVs averaged 17% and ranged from 6% for peanuts to 39% for fresh/frozen, boiled spinach. DISCUSSION
Those who regularly use food composition data to plan and evaluate diets usually need to know the average concentrations of nutrients in foods. However, it is useful
MACROELEMENTS
IN TABLE
kcd Wlngb
“eight of Icdlun sewi LO *edtan*ear@m
TOTAL
DIET
STUDY
FOODS
161
S-Continued
Petaraiun *edianIleaw.wn>
Calcium Media*ear+.%“,
PhOlpO.xYS l&dim “ean+_sdm,
Mmc,IM “edianlear@m,
162
PENNINGTON
AND
YOUNG
to consider the variability of nutrients in foods, and to be aware that foods consumed by patients or subjects may not contain precisely the same nutrient levels as specified in food composition tables. Nutrient variation may result from genetic, environmental, processing, and analytic variables. High variation (i.e., high CVs) does not mean that the data are unreliable, but high variability may limit the use of the data in certain situations. The data may serve to assessdiets, especially if multiple records are used, but variable data should be used with caution for 1-day diet records, metabolic studies, or diets of patients who must be closely monitored. Nutrient variability should be considered when recommending specific foods as sources of nutrients either for nutrition education or for patient counseling. The variation of a nutrient in a food, expressed by the CV, is more important, in a practical sense, for those foods indicated to be a source of a nutrient (e.g., calcium in milk, rather than calcium in root vegetables, or magnesium in dark green leafy vegetables, rather than magnesium in cakes and pies). In other words, one would hope for less variability of nutrients in those foods which are routinely suggested as sources for particular nutrients. The data obtained here indicate that average CVs of 14-20% for major sources of the nutrient elements reflect “usual” variability. (This is, of course, assuming appropriate sampling and analytical methodology.) CVs greater than this might reflect more specific reasons for variability and may need to be used with caution. An evaluation of the data by source categories is shown in Table 7. Source categories have been defined by FDA for nutrients with USRDAs (U.S. Recommended Daily Allowances) (Pennington et al., 1990). (Calcium, phosphorus, and magnesium have USRDAs, but sodium and potassium do not.) An excellent source provides 40% or more of the USRDA per serving, a good source provides 25% or more of the USRDA, and a fair source provides 10% or more of the USRDA. The excellent, good, and fair source criteria are, respectively, 400, 250, and 100 mg/serving for calcium and phosphorus where the USRDA is 1000 mg/day; and 160, 100, and 40 mg/serving for magnesium where the USRDA is 400 mg/day. The eight good sources of calcium had an average CV of 15% (range 12-23%); the 18 fair sources had an average CV of 26% (range 16-38%). Foods with higher CVs included fast food hamburger (CV = 32%) vanilla ice milk (CV = 34%) fried shrimp
MACROELEMENTS
IN
TOTAL TABLE
DIET
STUDY
FOODS
6
AVERAGELEVELSOFTHEELEMENTSPERSERVINGBYFOODGROUP
Food
oroup
(n)
Sodium
Potassium,
Calcium (mg
per
Phosphorus
Magnesium
21.9
servlngl
Vegetables Leafy
(7)
Sten/flnvrr
(4)
Beans/peas
(9)
Pact/tuber
(131
Other
117)
Fruits
, juices
Grqin
products
Cookrd RTE
163
70
24
24
157
25
35
9.6
a0
278
33
98
35.3
106
317
28
50
18.6
179
192
18
30
14.4
4
215
16
20
13.1
(25)
grjins
(5)
cereals
Bread,
207
(71
70
41
9
46
14.7
187
171
21
92
33.0
ieo
50
31
68
11.1
118
175
16
95
45.6
rolls,
pasta,
etc.
Nuts
(3)
Eggs
(31
Dairy
(13)
products
Animal
(11)
10:
71
34
102
6.7
232
312
243
215
24.7
flesh
Fish
(4)
Poultry Meat
196
40
154
78.6
260
18
179
23.0
'7F
273
22
197
21.0
318
62
6
4R
5.1
829
420
110
213
41.4
832
178
42
61
13.7
262 (3)
e6
(11)
Breakfast/luncheon
meats
(51
Mixed
dishes
Soups
(4)
(12)
Desserts Dairy-based
(5)
201
309
161
188
28.5
Grain-based
(71
216
73
30
77
12.1
172
98
40
50
10.6
39
34
3
7
4.3
56
12
4
6
0.5
14
46
8
15
5.7
37
339
76
77
37.3
226
15
1R
13.1
5
92
34
65
18.3
7
26
17
12
2.1
45
208
28
122
14.9
40
178
43
75
16.2
46
166
95
91
13.3
Other
(51
Sweeteners Fats
and
(6) sa"ces
Severaoes
(9)
(131
Strained/junior
foods
Veqetables
17)
Fruits,
juirrs
Cereals
(7)
Formulas
(9)
(2)
Meat/poultry
(3)
Dinners
(9)
Dessert
Ill
8
163
164
PENNINGTON
AND YOUNG
TABLE 7 SOURCE
CATEGORIES
FOR CALCIUM,
PHOSPHORUS,
AND MAGNESIUM
C.3
No.
of
P
CV mean
No.
(range)
foods
foods
of
Good
sourcea
CV mean
No.
(range)
foods
source
a The excellent
of
1
(%I
22
0
-
8
15 (12-23)
7
16 (8-21)
0
-
26 (16-38)
53
14 (6-31)
14
15 (6-29)
phosphorus
was the
frozen,
fried
chicken
lowfat
plain
yogurt;
fast
milk;
lowfat
strawberry
milk.
The good
of
FEUDS
(range)
18
source
STUDY
CV mean
(%I
0
sourceb
(Fair)
DIET
Mg
(%)
Excellent
IN TOTAL
dinner. b The good
sources
chocolate lowfat
of
calcium
milkshake; milk,
phosphorus
buttermilk;
skim
milk,
and evaporated
chocolate included
pudding;
fast
noodle
casserole;
food
included
fried
beef/calf
chocolate and
liver;
milkshake;
cottage lowfat
plain
cheese; yogurt;
food yogurt;
sources
of
chocolate chicken
lasagna.
(CV = 34%) chicken noodle casserole (CV = 36%), and tomato soup (CV = 38%). The one excellent source of phosphorus had a CV of 22%; the seven good sources had an average CV of 16% (range 8-2 1%); the 53 fair sources had an average CV of 14% (range 6% for peanuts to 3 1% for tomato soup). There were no excellent or good sources of magnesium. The 14 fair sources had an average CV of 15% (range 7% for peanut butter to 29% for granola). ACKNOWLEDGMENTS The authors acknowledge the laboratory analyses performed by the chemists and technicians of the FDA Total Diet Laboratory in Kansas City, Missouri; and the computer assistance provided by David Graham of the Total Diet Laboratory, Dennis Wilson of the Division of Mathematics, and Sharon Schoen of the Division of Information Resources Management in the FDA Center for Food Safety and Applied Nutrition, Washington, D.C.
REFERENCES GEBHARDT,
S. E., CUTRUFELLI,
Juices: Raw,
Processed,
R., AND MATTHEWS,
Prepared.
Nutrition Information Service.
R. H. (1982).
Composition
ofFoods.
Fruits
and Fruit
Agriculture Handbook No. 8-9. U.S. Department of Agriculture, Human
MACROELEMENTS
IN
TOTAL
DIET
STUDY
FOODS
165
GRUBBS, F. E. (1969). Procedures for detecting outlying observations in samples. Technometrics ll( I), l21. KEITH, L. H., CRUMMETT, W., DEEGAN, J., JR., LIBBY, R. A., TAYLOR, J. K., AND WENTLER, G. (1983). Principles of environmental analysis. Anal. Chem. 53, 22 lo-22 18. MARTS, R. W., AND MELOAN, C. E. (1982). Rapid digestion/determination of food composites by ICP, SARAP Report, Vol. 6, No. 105-79. Department of Health and Human Services. PENNINGTON,J. A. T. (1982). Documentation for the Revised Total Diet Study: Food List and Diets. National Technical Information Service, PB82 I92 154, Springfield, VA. PENNINGTON, J. A. T. (1983). Revision of the Total Diet Study food list and diets. .I Amer. Diet. Assoc. 82, 166-173. PENNINGTON,J. A. T., AND GUNDERSON, E. L. (1987). A history of the Food and Drug Administration’s Total Diet Study, 1961 to 1987. J. Assoc. Ofl Anal. Chem. 70, 772-782. PENNINGTON,J. A. T., AND YOUNG, B. E. (in press) Total Diet Study nutritional elements, 1982-1989. J. Amer. Diet. Assoc. PENNINGTON, J. A. T., AND YOUNG, B. E. (1990). Iron, zinc, copper, manganese, selenium and iodine in foods from the United States Total Diet Study. J. Food Compos. Anal. 3, I66- 184. PENNINGTON, J. A. T., WILKENING, V. L., AND VANDERVEEN, J. E. (1990). Viewpoint: Descriptive terms for food labeling. J. Nutr. Ed. 22, 5 l-54. PENNINGTON,J. A. T., YOUNG, B. E., AND WILSON, D. B. (1989). Nutritional elements in U.S. diets: Results from the Total Diet Study, 1982- 1986. J. Amer. Diet. Assoc. 89, 659-664. PENNINGTON,J. A. T., YOUNG, B. E., WILSON, D. B., JOHNSON,R. D., AND VANDERVEEN, J. E. (1986). Mineral content of food and total diets: The Selected Minerals in Foods Survey, 1982-1984. J. Amer. Diet. Assoc. 86, 876-89 1.
OF FOOD
COMPOSITION
AND ANALYSIS
3, 145- 165 (1990)
Sodium, Potassium, Calcium, Phosphorus, and Magnesium in Foods from the United States Total Diet Study J.A.T.PENNINGTON*" Food
and Drug Administration, *Division and tKansas City District Q&e, Received
March
AND B.
YOUNG?
qf Nutrition, Wushington, D.C. 20204. Kansas City, Missouri 64106, U.S.A.
6, 1990, and in revised
form
August
U.S.A.;
10, 1990
Data on the concentrations of sodium, potassium, calcium, phosphorus, and magnesium in the 234 foods of the United States Total Diet Study from 1982 to 1989 are summarized per 100 g and per typical serving portion. Per serving, mixed dishes and soups were higher in sodium; mixed dishes, root/tuber vegetables, and dairy products were higher in potassium; dairy products were higher in calcium; dairy products, mixed dishes, and animal flesh were higher in phosphorus; and nuts, mixed dishes, and legumes were higher in magnesium. Of the top 20 foods highest in each element per serving, the coefficients of variation averaged 20% (range IO-48%) for sodium, 15% (range 2-47%) for potassium, 21% (range 12-24%) for calcium, 14% (range 7-22%) for phosphorus, and 17% (range 7-24%) for magnesium. Nutrient variation reflects genetic, environmental, processing, and analytic factors. Sodium variability most likely reflects the variable amount of salt added to foods and recipe ingredients by industry. o 1990 Academic press, hc.
INTRODUCTION
The United States Total Diet Study is a yearly program which monitors the levels of contaminants and nutrients in the food supply and diets of selected age-sex groups (Pennington and Gunderson, 1987). The food list and diets are periodically revised when new information from national food consumption surveys becomes available. The current program (based on the 1982 revision) includes the collection and analyses of 234 core foods four times per year (Pennington, 1982, 1983). The nutritional evaluation of these foods includes analyses for 11 mineral elements: the macroelements sodium, potassium, calcium, phosphorus, and magnesium; and the microelements iron, zinc, copper, manganese, selenium, and iodine. Previous papers have presented the intakes of these elements for eight age-sex groups from 1982 to 1984 (Pennington et al., 1986), from 1982 to 1986 (Pennington et al., 1989), and from 1982 to 1989 (Pennington and Young, 1990). This paper presents the concentrations of the macroelements in the Total Diet Study foods and food groups from 1982 to 1989; the following paper presents results for the microelements. METHODS
AND
MATERIALS
The Total Diet Study foods are collected approximately four times per year, once from each of the four geographic regions of the United States (east, central, west, and south). The collection within a geographical area consists of the purchase of 246 foods and ingredients from each of three cities. The foods are purchased from supermarkets ’ To whom
correspondence
should
be addressed.
145
0889-1575/90
$3.00
Copyright 0 1990 by Academic Press, Inc. All rights of reproduction in any form reserved.
146
PENNINGTON
AND TABLE
TOTAL
DIET
STUDY
YOUNG
I
COLLECTION
LOCATIONS
Location
Date
April
1982
July
Buffalo,
1982
November February
June
CT;
CA; Phoenix,
Green
1983
Norfolk,
VA; Atlanta,
Boston,
MA; New York,
1983 1983
December
1983-
January
1984
March-April
Bay,
Honolulu, Topeka,
WI;
AZ;
1982
September
June-July
1984
September-
Chicago,
Newark,
Salt
NJ
Lake
IL;
City,
Detroit,
UT
MI
GA; Jacksonville,
FL
NY; Montgomwyville,
HI;
San Diego,
KS; St.
Louis,
1984 Beaumont/Port Juan,
October
NY; Hartford,
Fresno,
CA; Portland, MO; Dayton,
Arthur/Orange,
TX;
PA OR
OH
Nashville,
TN;
San
PR
Lancaster,
PA;
Tacoma,
Nassau-Suffolk,
WA; Bakersfield,
NY; Rochester,
CA; Salt
Lake
NY
City,
UT
1984
January-February
St.
Cloud,
MN; Rockford,
IL;
Flint,
MI
1985 April July
1985 1985
October-November 1985 January April
Dallas/Ft.
Worth,
Portland,
ME; Long
Los
Angeles/Long
Falls, 1986 1986
Macon,
GA; Charleston,
BeachlAsbury
Beach,
Park,
CA; Sacramento,
NJ;
WV New York,
NY
CA; Sioux
SD
Chattanooga, Cleveland, Wichita,
TX;
TN;
Ft.
Smith,
OH; Davenport,
AR; IA/Reek
Miami,
FL
Island-Moline,
IL;
KS
and fast-food chains within each city. The cities selected for inclusion in the program represent standard metropolitan statistical areas and are within commuting distance of a Food and Drug Administration (FDA) field office. Table 1 indicates the locations of the collections for the Total Diet Study program from 1982 to 1989. The same foods were purchased from the three cities over a 4week period. The foods from each weekly purchase were sent by air freight (packed in dry ice where necessary) to the Total Diet Laboratory in the FDA Kansas City District Office. Upon arrival in Kansas City the foods were logged in and checked to be sure the appropriate items were collected in requested quantities. If discrepancies were noted or if foods were damaged, the field office responsible for the delivery was asked to repeat the collection of the needed foods.
MACROELEMENTS
IN
TOTAL
July
STUDY
147
FOODS
l-Continued
TABLE
Date
DIET
Location
1986
Spokane,
WA; Albuquerque,
October
1986
Providence,
Januarg
1987
Memphis,
April-May
1987
RI; TN;
NM; Denver,
Albany,
Omaha,
NE; Fargo,
Brownsville/Harlingen/San Baton
July-Auqust
Rouge,
Portland,
CO
NY; Pittsburgh,
PA
ND
Benito,
TX;
Birmingham,
AL;
LA
OR; Fresno,
CA; Phoeniz,
AZ
1987 October
1987
Peoria,
January
1988
Baltimore,
March-April
El
IL;
Paso,
Indianapolis,
IN;
MD; Charleston, TX;
Pueblo,
Milwaukee,
SC; Tallahassee,
CO; Reno,
WI FL
NV
1988
June-July August November January
1988
Syracuse,
1988 1988
NY; New York
Ponce,
PR; Jackson,
Akron,
OH; Battle
Nassau/Suffolk,
1989
Passaic,
(Berqen
Co.,
MS; Columbus, Creek,
MI;
NJ);
Lincoln,
NY; Washington,
Manchester,
NH
GA
DC;
NE Patterson/Clifton/
NJ
Foods that required preparation or that were ingredients for mixed dishes were sent to a contract kitchen in close proximity to the Kansas City Laboratory. At the contract kitchen the foods were rinsed, cooked, and/or otherwise prepared for TABLE
2
LIMITSOFQUANTITATION (L,)FoR SODIUM,POTASSIUM,CALCIUM, PHOSPHORUS,AND MAGNESIUM FORTOTALDIETSTUDY FOODS
Element
Lq (mg/lOO
Na
0.20
K
0.50
Ca
0.20
P
0.050
Mg
0.10
gl
148
PENNINGTON
AND TABLE
QUALITY
CONTROL
EVALUATION
YOUNG
3 OF TOTAL
DIET
Spiked Percent
a NIST Standard
STUDY
DATA
SRMa
recovery
+ SD (n)
Percent
recovery
+ SD (n)
100.4
c
7.0
(456)
89.3
+ 6.3
(222)
100.8
t
7.8
(456)
91.7
+ 7.6
(226)
96.8
+ 11.7
(435)
96.4
+ 8.6
(216)
98.0
+
7.8
(437)
83.7
+ 5.6
(216)
97.8
-+
8.0
(456)
97.7
+ 6.6
(223)
Reference
Material
oyster
tissue.
consumption. The water used for rinsing and cooking procedures was deionized. Noniodized salt was added to mixed dishes as specified by recipe and to several other foods as indicated by package instructions, but other foods (e.g., meats and vegetables) were not salted. The prepared foods were then returned to the laboratory. The similar foods from the three cities were cornposited. Each of the 234 foods for a single collection represented an equal weight composite from the three cities of the geographical area. Aliquots of each of the 234 composite foods were then analyzed for nutritional elements. The five macroelements were determined by inductively coupled plasma atomic emission spectrometry (Marts and Meloan, 1982). Twenty-eight test portions of each food were analyzed for sodium, potassium, and magnesium. For calcium and phosphorus, which were not determined in the first collection, there were 27 analyses. In total, there were 32,393 analyses. The foods were analyzed in series with 15-30 test portions per series. For each element being determined, the series analysis included two reagent blanks, duplicate analysis of at least one test portion, at least one spiked recovery analysis, and at least one standard reference material (SRM) from the National Institute of Standards and Technology (NET). The limits of quantitation for the analytical methodology (Table 2) were based on repetitive analyses of blank solutions (Keith et al., 1983). Values below the limits of quantitation were reported as zeros. Values for sodium, potassium, calcium, and phosphorus were rounded to the nearest whole number; values for magnesium were carried to one decimal point. The data were evaluated for outliers by means of the Grubbs extreme deviation test (Grubbs, 1969). Median and mean (plus or minus standard deviation) concentrations of the five elements in the 234 foods were determined per 100 g and per typical serving portion. The concentrations of the elements by food
MACROELEMENTS
IN
TOTAL TABLE
DIET
STUDY
149
FOODS
4
SODIUM,POTASSIUM,CALCIUM,PHOSPHORUS,ANDMAGNESIUMCONTENTOFTOTAL FOODSIN~~PER IOOg" rood YBlW" scdim PotaIll"m CDlCIL.m PhoM!or"r
DIETSTUDY q all”EIIM
150
PENNINGTON TABLE
AND
YOUNG
4-Continued
MACROELEMENTS
IN TABLE
TOTAL
DIET
STUDY
FOODS
151
&-Continued
groups per serving portion were determined. Coefficients of variation (CVs) were calculated for foods highest in each element per serving to assessthe variability of the elements.
152
PENNINGTON TABLE
laod
Yale?”
Pcdlrn
POIBEII”m
AND
YOUNG
4-Continued CalclM
RESULTS
Results of the quality control measures are shown in Table 3. There were 12-20 spiked recoveries per collection. Average spiked recoveries ranged from 96.8 to 100.8%, and recoveries for SRMs ranged from 83.7 to 97.7%.
154
PENNINGTON TABLE
AND 4-Continued
YOUNG
MACROELEMENTS
IN
TOTAL
DIET
STUDY
FOODS
155
An evaluation for outliers resulted in the omission of two sets of results (one of pancake syrup and one of chocolate powder for milk) and the omission of 10 values for sodium and two values for potassium. Thus, of 32,393 analyses, results for 22 (0.07%) were identified as outliers. The medians and means with standard deviations for the macroelements in the 234 Total Diet Study foods are presented in Table 4 per 100 g and in Table 5 per typical serving portions of table-ready, edible food. Table 6 presents the average levels of the elements per serving by food group. By food groups, the major sources of the macroelements are mixed dishes and soups for sodium; mixed dishes, root/tuber vegetables, and dairy products for potassium; dairy products for calcium; dairy products, mixed dishes, and animal flesh for phosphorus; and nuts, mixed dishes, and legumes for magnesium. Of the seven strained/ junior food groups, dessert and dinners were highest in sodium, vegetables were highest in potassium, dessert and vegetables were highest in calcium, meat/poultry were highest in phosphorus, and vegetables were highest in magnesium. The 20 foods (excluding strained/junior foods) highest in sodium (575-1730 mg/ serving) included 11 mixed dishes, cured ham, four soups, cottage cheese, sauerkraut, tomato sauce, and dill pickles. These were all products to which salt had been added by industry or by homemade recipe. Some of the recipe ingredients also contained salt added by industry (e.g., tomato paste in the homemade lasagna). The CVs for the sodium content of these products averaged 20% and ranged from 10 to 48%; the higher CVs were for vegetable beef soup (CV = 35%) and homemade beef and vegetable stew (CV = 48%). The variability of sodium in these products is most likely due to the variable amounts of salt added by industry. The 20 foods highest in potassium (393-790 mg/serving) included five mixed dishes, chocolate milkshake, seven vegetables, three fruits, three dairy items, and tomato soup. CVs for these products averaged 15% and ranged from 2% for avocados to 47% for cantaloupe. The 20 foods highest in calcium (127-350 mg/serving) included 11 dairy products, three dairy desserts, three mixed dishes, collards, pancakes, and tomato soup. CVs averaged 21% and ranged from 11 to 38% with the higher CVs for vanilla ice milk (CV = 34%) chicken noodle casserole (CV = 36%) and tomato soup (CV = 38%). The variability of calcium in some products may reflect recipe formulations (i.e., the amounts of milk, cheese, or cream in these products).
156
PENNINGTON
AND TABLE
YOUNG
5
SODIUM,POTASSIUM,CALCIUM,PHOSPHORUS,ANDMAGNESIUM CONTENTOFTOTALDIETSTUDY FOODSIN~~PERSERVING'
MACROELEMENTS
IN
TOTAL
TABLE Food r.rvimb
Yeighrof *cd,uI rervins (‘I, Hfdian*earpAm
P.tasIIm *f-San lean*sdw
DIET
STUDY
FOODS
157
S-Continued ca,cim *cd,an*eMt-sdm
Phorphcmn edin *earerdm
-iul “edianlleac-rdm
PENNINGTON TABLE
Pm.SSI”n
AND
YOUNG
5-Continued Calclm
The 20 foods highest in phosphorus (209-4 15 mg/serving) included six mixed dishes, three animal flesh items, seven dairy products, two dairy desserts, pancakes, and raisin bran cereal. CVs averaged 14% and ranged from 7% for evaporated canned milk to 22% for frozen, fried chicken dinner. The 20 foods highest in magnesium (37.5-83. I mg/serving) included two ready-to-
eat cereals, six mixed dishes, eight vegetables (spinach and legumes), two nuts, chocolate milkshake, and fried shrimp. CVs averaged 17% and ranged from 6% for peanuts to 39% for fresh/frozen, boiled spinach. DISCUSSION
Those who regularly use food composition data to plan and evaluate diets usually need to know the average concentrations of nutrients in foods. However, it is useful
MACROELEMENTS
IN TABLE
kcd Wlngb
“eight of Icdlun sewi LO *edtan*ear@m
TOTAL
DIET
STUDY
FOODS
161
S-Continued
Petaraiun *edianIleaw.wn>
Calcium Media*ear+.%“,
PhOlpO.xYS l&dim “ean+_sdm,
Mmc,IM “edianlear@m,
162
PENNINGTON
AND
YOUNG
to consider the variability of nutrients in foods, and to be aware that foods consumed by patients or subjects may not contain precisely the same nutrient levels as specified in food composition tables. Nutrient variation may result from genetic, environmental, processing, and analytic variables. High variation (i.e., high CVs) does not mean that the data are unreliable, but high variability may limit the use of the data in certain situations. The data may serve to assessdiets, especially if multiple records are used, but variable data should be used with caution for 1-day diet records, metabolic studies, or diets of patients who must be closely monitored. Nutrient variability should be considered when recommending specific foods as sources of nutrients either for nutrition education or for patient counseling. The variation of a nutrient in a food, expressed by the CV, is more important, in a practical sense, for those foods indicated to be a source of a nutrient (e.g., calcium in milk, rather than calcium in root vegetables, or magnesium in dark green leafy vegetables, rather than magnesium in cakes and pies). In other words, one would hope for less variability of nutrients in those foods which are routinely suggested as sources for particular nutrients. The data obtained here indicate that average CVs of 14-20% for major sources of the nutrient elements reflect “usual” variability. (This is, of course, assuming appropriate sampling and analytical methodology.) CVs greater than this might reflect more specific reasons for variability and may need to be used with caution. An evaluation of the data by source categories is shown in Table 7. Source categories have been defined by FDA for nutrients with USRDAs (U.S. Recommended Daily Allowances) (Pennington et al., 1990). (Calcium, phosphorus, and magnesium have USRDAs, but sodium and potassium do not.) An excellent source provides 40% or more of the USRDA per serving, a good source provides 25% or more of the USRDA, and a fair source provides 10% or more of the USRDA. The excellent, good, and fair source criteria are, respectively, 400, 250, and 100 mg/serving for calcium and phosphorus where the USRDA is 1000 mg/day; and 160, 100, and 40 mg/serving for magnesium where the USRDA is 400 mg/day. The eight good sources of calcium had an average CV of 15% (range 12-23%); the 18 fair sources had an average CV of 26% (range 16-38%). Foods with higher CVs included fast food hamburger (CV = 32%) vanilla ice milk (CV = 34%) fried shrimp
MACROELEMENTS
IN
TOTAL TABLE
DIET
STUDY
FOODS
6
AVERAGELEVELSOFTHEELEMENTSPERSERVINGBYFOODGROUP
Food
oroup
(n)
Sodium
Potassium,
Calcium (mg
per
Phosphorus
Magnesium
21.9
servlngl
Vegetables Leafy
(7)
Sten/flnvrr
(4)
Beans/peas
(9)
Pact/tuber
(131
Other
117)
Fruits
, juices
Grqin
products
Cookrd RTE
163
70
24
24
157
25
35
9.6
a0
278
33
98
35.3
106
317
28
50
18.6
179
192
18
30
14.4
4
215
16
20
13.1
(25)
grjins
(5)
cereals
Bread,
207
(71
70
41
9
46
14.7
187
171
21
92
33.0
ieo
50
31
68
11.1
118
175
16
95
45.6
rolls,
pasta,
etc.
Nuts
(3)
Eggs
(31
Dairy
(13)
products
Animal
(11)
10:
71
34
102
6.7
232
312
243
215
24.7
flesh
Fish
(4)
Poultry Meat
196
40
154
78.6
260
18
179
23.0
'7F
273
22
197
21.0
318
62
6
4R
5.1
829
420
110
213
41.4
832
178
42
61
13.7
262 (3)
e6
(11)
Breakfast/luncheon
meats
(51
Mixed
dishes
Soups
(4)
(12)
Desserts Dairy-based
(5)
201
309
161
188
28.5
Grain-based
(71
216
73
30
77
12.1
172
98
40
50
10.6
39
34
3
7
4.3
56
12
4
6
0.5
14
46
8
15
5.7
37
339
76
77
37.3
226
15
1R
13.1
5
92
34
65
18.3
7
26
17
12
2.1
45
208
28
122
14.9
40
178
43
75
16.2
46
166
95
91
13.3
Other
(51
Sweeteners Fats
and
(6) sa"ces
Severaoes
(9)
(131
Strained/junior
foods
Veqetables
17)
Fruits,
juirrs
Cereals
(7)
Formulas
(9)
(2)
Meat/poultry
(3)
Dinners
(9)
Dessert
Ill
8
163
164
PENNINGTON
AND YOUNG
TABLE 7 SOURCE
CATEGORIES
FOR CALCIUM,
PHOSPHORUS,
AND MAGNESIUM
C.3
No.
of
P
CV mean
No.
(range)
foods
foods
of
Good
sourcea
CV mean
No.
(range)
foods
source
a The excellent
of
1
(%I
22
0
-
8
15 (12-23)
7
16 (8-21)
0
-
26 (16-38)
53
14 (6-31)
14
15 (6-29)
phosphorus
was the
frozen,
fried
chicken
lowfat
plain
yogurt;
fast
milk;
lowfat
strawberry
milk.
The good
of
FEUDS
(range)
18
source
STUDY
CV mean
(%I
0
sourceb
(Fair)
DIET
Mg
(%)
Excellent
IN TOTAL
dinner. b The good
sources
chocolate lowfat
of
calcium
milkshake; milk,
phosphorus
buttermilk;
skim
milk,
and evaporated
chocolate included
pudding;
fast
noodle
casserole;
food
included
fried
beef/calf
chocolate and
liver;
milkshake;
cottage lowfat
plain
cheese; yogurt;
food yogurt;
sources
of
chocolate chicken
lasagna.
(CV = 34%) chicken noodle casserole (CV = 36%), and tomato soup (CV = 38%). The one excellent source of phosphorus had a CV of 22%; the seven good sources had an average CV of 16% (range 8-2 1%); the 53 fair sources had an average CV of 14% (range 6% for peanuts to 3 1% for tomato soup). There were no excellent or good sources of magnesium. The 14 fair sources had an average CV of 15% (range 7% for peanut butter to 29% for granola). ACKNOWLEDGMENTS The authors acknowledge the laboratory analyses performed by the chemists and technicians of the FDA Total Diet Laboratory in Kansas City, Missouri; and the computer assistance provided by David Graham of the Total Diet Laboratory, Dennis Wilson of the Division of Mathematics, and Sharon Schoen of the Division of Information Resources Management in the FDA Center for Food Safety and Applied Nutrition, Washington, D.C.
REFERENCES GEBHARDT,
S. E., CUTRUFELLI,
Juices: Raw,
Processed,
R., AND MATTHEWS,
Prepared.
Nutrition Information Service.
R. H. (1982).
Composition
ofFoods.
Fruits
and Fruit
Agriculture Handbook No. 8-9. U.S. Department of Agriculture, Human
MACROELEMENTS
IN
TOTAL
DIET
STUDY
FOODS
165
GRUBBS, F. E. (1969). Procedures for detecting outlying observations in samples. Technometrics ll( I), l21. KEITH, L. H., CRUMMETT, W., DEEGAN, J., JR., LIBBY, R. A., TAYLOR, J. K., AND WENTLER, G. (1983). Principles of environmental analysis. Anal. Chem. 53, 22 lo-22 18. MARTS, R. W., AND MELOAN, C. E. (1982). Rapid digestion/determination of food composites by ICP, SARAP Report, Vol. 6, No. 105-79. Department of Health and Human Services. PENNINGTON,J. A. T. (1982). Documentation for the Revised Total Diet Study: Food List and Diets. National Technical Information Service, PB82 I92 154, Springfield, VA. PENNINGTON, J. A. T. (1983). Revision of the Total Diet Study food list and diets. .I Amer. Diet. Assoc. 82, 166-173. PENNINGTON,J. A. T., AND GUNDERSON, E. L. (1987). A history of the Food and Drug Administration’s Total Diet Study, 1961 to 1987. J. Assoc. Ofl Anal. Chem. 70, 772-782. PENNINGTON,J. A. T., AND YOUNG, B. E. (in press) Total Diet Study nutritional elements, 1982-1989. J. Amer. Diet. Assoc. PENNINGTON, J. A. T., AND YOUNG, B. E. (1990). Iron, zinc, copper, manganese, selenium and iodine in foods from the United States Total Diet Study. J. Food Compos. Anal. 3, I66- 184. PENNINGTON, J. A. T., WILKENING, V. L., AND VANDERVEEN, J. E. (1990). Viewpoint: Descriptive terms for food labeling. J. Nutr. Ed. 22, 5 l-54. PENNINGTON,J. A. T., YOUNG, B. E., AND WILSON, D. B. (1989). Nutritional elements in U.S. diets: Results from the Total Diet Study, 1982- 1986. J. Amer. Diet. Assoc. 89, 659-664. PENNINGTON,J. A. T., YOUNG, B. E., WILSON, D. B., JOHNSON,R. D., AND VANDERVEEN, J. E. (1986). Mineral content of food and total diets: The Selected Minerals in Foods Survey, 1982-1984. J. Amer. Diet. Assoc. 86, 876-89 1.