Contribution of Dairy Products to Dietary Potassium Intake in the United States Population Carla R. McGill, PhD, RD, Victor L. Fulgoni, III, PhD, Douglas DiRienzo, PhD, Peter J. Huth, PhD, Anne C. Kurilich, PhD, Gregory D. Miller, PhD, FACN Healthy Science Communications, LLC, Bradenton, Florida (C.R.M.), Nutrition Impact, LLC, Battle Creek, Michigan (V.F.), National Dairy Council, Rosemont, Illinois (D.D., P.J.H., A.C.K., G.D.M.) Key words: potassium, dairy, nutrient intake, dietary surveys, NHANES Objective: Adequate dietary potassium intake is associated with a reduced risk of cardiovascular and other chronic diseases. The Dietary Guidelines for Americans 2005 identifies milk and milk products as a major contributor of dietary potassium and lists dairy products, along with fruits and vegetables, as food groups to encourage. This paper further examines the impact of dairy consumption on the potassium intake of the United States (US) population. Methods: Using data from the National Health and Nutrition Examination Survey (NHANES) 1999 –2002 we determined potassium intakes for various age groups of individuals who met the recommended number of dairy servings compared to those who did not. We also examined the impact of dairy servings consumed on mean and median potassium intakes and compared intakes to the age-appropriate Adequate Intakes (AI). Results: For all age groups, mean and median potassium intakes did not meet the respective AI. Mean potassium intakes were significantly greater in those subjects who met dairy intake recommendations compared to those who did not for all age groups. Mean and median potassium intakes increased with increasing dairy intake but were below current intake recommendations for all age groups analyzed. For adults age 19 to 50, 16.1% consumed the recommended number of dairy servings per day. For those 51 and older, 10.7% met current dairy intake recommendations. Conclusions: Consumption of dairy products is below current recommendations which contributes in part to suboptimal dietary potassium intakes among a large proportion of the US population. Since adequate potassium intake is associated with decreased risk of chronic disease, consumption of a variety of potassium-rich foods, including fruits, vegetables and low-fat and fat free dairy products, should continue to be encouraged.
of potassium per 8-ounce (240 mL) serving of yogurt or fluid milk (Table 1). In addition to potassium, dairy products are also significant sources of calcium, vitamin D, vitamin A, phosphorous, magnesium, protein and several B vitamins [2,3]. Adequate dietary potassium intake has been strongly associated with a reduced risk of cardiovascular disease (CVD), specifically a reduced risk of hypertension and stroke . The US Food and Drug Administration (FDA) currently allows foods that are good sources of potassium, and that meet other nutrient requirements, to carry a health claim on the label that informs consumers of the link between potassium intake and reduced risk of high blood pressure and stroke . Consumer awareness of the link between dietary potassium and reduced
Potassium, the most abundant intracellular cation, is important for membrane transport, energy metabolism, fluid balance and proper cell functioning. Potassium has a critical role in membrane polarization and abnormal potassium homeostasis can result in disorders in cardiac, muscle and neurological function . Potassium is present in most food groups; however only a limited number of foods are classified as good sources of potassium containing 350 mg or more per serving. Good sources of potassium include dairy products, fruits, vegetables, whole grains, nuts, seeds and dried beans. Dairy products that are good sources of potassium contain 350 to 531 mg
Address reprint requests to: Carla R. McGill, Ph.D., R.D., Healthy Science Communications, LLC, 7059 Strand Circle, Bradenton, FL 34203. E-mail: [email protected]
Dr. Kurilich’s present address is Quaker/Tropicana/Gatorade, Barrington, IL.
Journal of the American College of Nutrition, Vol. 27, No. 1, 44–50 (2008) Published by the American College of Nutrition 44
Contribution of Dairy Products to Dietary Potassium Intake Table 1. Potassium Content of Select Dairy Foods Serving Size Cheese, cottage, lowfat, 2% milkfat Milk, chocolate, reduced fat Milk, 1% milkfat Milk, skim Milk, 2% milkfat Milk, 3.25% milkfat Yogurt, fruit Yogurt, plain, lowfat Yogurt, plain, whole milk
1 1 1 1 1 1 8 8 8
cup cup cup cup cup cup ounces ounces ounces
Potassium per Serving, mg 217 423 366 366 366 349 443 531 352
Source: USDA National Nutrient Database for Standard Reference, Release 18.
risk of CVD is low . The Dietary Approaches to Stop Hypertension (DASH) study demonstrated that the addition of low-fat dairy products to a diet high in fruits and vegetables significantly reduced blood pressure . The DASH diet included two to three dairy servings along with eight to 10 servings of fruit and vegetables per day for eight weeks. Significantly greater reductions in both systolic and diastolic blood pressure were observed with the diet containing dairy plus fruits and vegetables compared to the diet with fruits and vegetables alone . Most North Americans consume substantially less than the recommended number of daily servings of dairy, whole grains, fruits and vegetables . As a result, potassium intakes in the US population have been reported to be below recommended levels . It is our hypothesis that dairy products make a significant contribution to dietary potassium intake. The Dietary Guidelines for Americans, 2005, which includes the Food Guidance System (FGS) MyPyramid, recommends two servings of dairy products per day for those 8 years and younger and three servings per day for those 9 years and older . These recommendations were the result of extensive reviews by USDA to assess diet patterns suggested by the FGS resulting in the development of the current food groups and subgroup composites based on frequency of consumption of foods within each group and their nutrient profiles expected per serving as reported in food consumption surveys [9,10]. To examine recent intakes of potassium in the US population we analyzed data from the National Health and Nutrition Examination Survey (NHANES) 1999 –2002 and compared intakes to the Adequate Intake (AI) for potassium established by the Institute of Medicine (IOM) (Table 2) [11,12].
MATERIALS AND METHODS The data used in these analyses were from NHANES 1999 – 2002. NHANES is a stratified multistage probability sample of the US population based on a series of annual surveys . Dietary information was obtained via a 24-hour recall questionnaire. Subjects from the NHANES datasets were selected
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on stratified, clustered, multistage techniques with oversampling of select groups (e.g., low income persons, certain ethnic groups, certain age groups, etc.), thus appropriate sample weights must be utilized to ensure results are representative of the US population. Numbers of dairy servings were obtained from version 2 of the Pyramid Servings Database . We only used data for non-pregnant, non-lactating individuals aged 2 years and higher which had complete and reliable dietary records providing data for 16,388 subjects. Subjects were grouped into four age groups: 2– 8 years, 9 –18 years, 19 –50 years, and greater than 50 years. These age groups were chosen based on the age classifications created by the IOM and the fact that the FGS is used for Americans two years and older. We then separated subjects into two groups: 1) those that met or exceeded the number of dairy servings according to the FGS (2 or 3 servings depending on age) and 2) those that consumed less than the recommended number of dairy servings. Mean and median potassium intakes, average dairy serving intake and the percentage of the population meeting or not meeting the AI for potassium (Table 2) were calculated for all groups. Subjects were also separated into six groups based on dairy serving consumption (⬍1, 1–1.5, 1.5– 2.5, 2.5–3.5, 3.5– 4.5, and ⬎ 4.5 dairy servings per day). Mean and median potassium intakes, average dairy serving intake and the percentage of the population meeting or not meeting the AI for potassium were calculated for all these groups. If the mean potassium intake exceeded the AI for a particular age group, we concluded that the prevalence of inadequate potassium intake was low .
Statistical Analysis Analyses were conducted using SAS (Statistical Analysis System, Release 9.0 for Windows; SAS Institute, Cary NC) and SUDAAN (Release 9.0, Research Triangle Institute, Research Triangle Park, NC). Appropriate study specific sampling weights were employed to adjust for over-sampling of selected groups and survey non-response of some individuals in each study. Standard errors were estimated by the Taylor linearization technique of SUDDAN. Significant differences in mean
Table 2. Dietary Reference Intake for Potassium Males & Females 1–3 years 4–8 years 9–13 years 14–18 years 19–50 years ⬎50 years
Potassium Adequate Intake, mg/d1 3000 3800 4500 4700 4700 4700
Source: Food and Nutrition Board: “Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate.” Washington, DC: National Academies Press, 2004. 1 mg/d ⫽ milligrams per day.
Contribution of Dairy Products to Dietary Potassium Intake and median intakes were determined by students t-tests. Regression analyses were utilized to determine the impact of increased dairy consumption on potassium intake. Statistical significance was set at p ⬍ 0.05.
RESULTS Table 3 presents data on mean and median potassium intakes by age groups and the percentage of the groups that met the AI for potassium based on whether individuals within an age category met or did not meet the current FGS daily intake recommendation for dairy servings. For all age groups, both the mean and median potassium intakes by age did not meet the AI for potassium established by the Food and Nutrition Board (Tables 2 and 3). Hence, for all age groups it cannot be concluded that the likelihood of inadequate potassium intake is low. In children age two to 8 years the average number of dairy servings consumed was 2.1 ⫾ 0.05 servings per day, but only 47.4% of children in this age group met the FGS recommendations to consume 2 or more dairy servings per day. Children in this age group that met the FGS recommendations had a mean number of dairy servings of 3.27 ⫾ 0.05 (Table 3).
Children who did not meet the FGS dairy recommendations consumed an average of 1.04 ⫾ 0.02 dairy servings per day. Mean potassium intake of individuals in this age group who met FGS recommendations was 2547 ⫾ 40 mg/day which is significantly higher than the mean potassium intake of subjects who did not meet FGS recommendations for dairy (1688 ⫾ 35 mg; p ⬍ 0.05). The median potassium intake for subjects 2 to 8 years old who met FGS dairy recommendations was 2414 ⫾ 55 mg/day which is significantly higher than the median potassium intake for children aged 2 to 8 who did not meet FGS dairy recommendations (1574 ⫾ 40 mg/day, p ⬍ 0.05). Mean and median potassium intakes for the total age group and for both the subjects who met FGS recommendations and the subjects who did not meet FGS recommendations for dairy consumption did not meet the estimated AI for potassium. Of the children in this age group 12.9% met the estimated AI while for those children who did not consume the FGS recommended dairy servings 2.1% met the AI for potassium (Table 3). The mean potassium intake for the total group of subjects aged 9 to 18 years was 2381 ⫾ 41 mg/day and the median potassium intake was 2128 ⫾ 43 mg/day with an average dairy intake of 2.1 ⫾ 0.05 servings/day (Table 3). In this age group 22.9% of subjects met the FGS recommendations of 3 dairy servings per day consuming a mean of 4.65 ⫾ 0.09 servings per
Table 3. Impact of Meeting Food Guide System (FGS) Dairy Recommendation on Potassium Intake-NHANES 1999 –2002 Total for Age Group Children 2–8 Years Number of subjects Potassium Mean, mg/day Potassium Median, mg/day Potassium, % meeting AI3 Dairy Consumption, servings/day Children 9–18 Years Number of subjects Potassium Mean, mg/day Potassium Median, mg/day Potassium, % meeting AI Dairy Consumption, servings/day Adults 19–50 Years Number of subjects Potassium Mean, mg/day Potassium Median, mg/day Potassium, % meeting AI Dairy Consumption, servings/day Adults 51⫹ Years Number of subjects Potassium Mean, mg/day Potassium Median, mg/day Potassium, % meeting AI Dairy Consumption, servings/day
FGS Dairy Recommendations1 Met
2571 2095 (29)2 1967 (33)2 7.2 2.10 (0.05)2
1169 2547a (40) 2414a (55) 12.9 3.27a (0.05)
1402 1688b (35) 1574b (40) 2.1 1.04b (0.02)
4988 2381 (41) 2128 (430) 6.2 2.07 (0.05)
982 3473a (73) 3158a (71) 17.4 4.65a (0.09)
4006 2056b (25) 1885b (29) 2.8 1.30b (0.02)
4723 2773 (31) 2563 (33) 8.8 1.65 (0.03)
658 3958a (68) 3707a (77) 24.4 4.74a (0.10)
4065 2545b (30) 2349b (40) 5.8 1.06b (0.02)
4106 2727 (32) 2552 (38) 7.0 1.36 (0.03)
367 4044a (89) 3790a (91) 25.9 4.40a (0.11)
3739 2569b (28) 2415b (32) 4.7 1.00b (0.02)
Percentage Meeting FGS Dairy Recommendation
Food Guidance System (FGS) recommends 2 servings of dairy products per day for those 8 years and younger and 3 servings/day for those 9 years and older. (SEM). 3 AI ⫽ Adequate Intake. a,b Means or medians with different superscripts are significantly different, p ⬍ 0.05. 2
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Contribution of Dairy Products to Dietary Potassium Intake recommendations was significantly higher than the median intake for those who did not meet FGS dairy recommendations (p ⬍ 0.05, Table 3). For adults 19 to 50 years, 24.4% of those consuming three or more dairy servings per day met the AI for potassium compared to 5.8% of those who did not consume the FGS recommended dairy servings. For adults age 51⫹ years the total mean potassium intake was 2727 ⫾ 32 mg/day and the median intake was 2552 ⫾ 38 mg/day. In this group 10.7% met the FGS dairy recommendations of three servings per day consuming an average of 4.40 ⫾ 0.11 dairy servings per day. Mean potassium intake for adults 51⫹ years who met the FGS dairy recommendation was 4044 ⫾ 89 mg/day which was significantly higher than the mean potassium intake for adults in this age group who did not meet FGS dairy recommendations (2569 ⫾ 28 mg/day; p ⬍ 0.05) and who consumed an average of 1.00 ⫾ 0.02 dairy servings per day. The median potassium intake for the adults who met the FGS dairy recommendation was significantly higher than the mean potassium intake for the adults 51⫹ years who did not meet the FGS dairy recommendation (Table 3). For the adults in this age group who consumed three or more dairy servings per day, 25.9% met the AI for potassium compared to 4.7% of those who consumed less than 3 servings of dairy per day. Table 4 reports the impact of consuming increasing servings of dairy (⬍1 to ⬎4.5 servings/day) on potassium intake. Mean
day. Subjects in this age group who met FGS dairy recommendations had a mean potassium intake of 3473 ⫾ 73 mg/day which was significantly higher than the mean intake for subjects who did not meet FGS dairy recommendations (2056 ⫾ 25 mg, p ⬍ 0.05) and who consumed a mean of 1.30 ⫾ 0.02 dairy servings per day. The median potassium intake for the subjects who met FGS dairy recommendations was also significantly higher than the median intake for those who did not meet FGS dairy recommendations (3158 ⫾ 71 mg/day versus 1885 ⫾ 29 mg/day respectively, p ⬍ 0.05). For the subjects aged 9 to 18 and who consumed the FGS recommended dairy servings, 17.4% met the potassium AI compared to 2.8% for those subjects who did not consume the FGS recommended number of dairy servings. The mean potassium intake for the total group of adults age 19 to 50 years was 2773 ⫾ 31 mg/day; the AI for this group is 4700 mg (Table 2). The median potassium intake for this age group was 2563 ⫾ 33 mg. For this group of adults, 16.1% met the FGS dairy recommendations of 3 servings per day consuming a mean of 4.74 ⫾ 0.10 servings per day. The mean potassium intake for adults 19 to 50 years who met FGS dairy recommendations was 3958 ⫾ 68 mg/day compared to 2545 ⫾ 30 mg/day for adults in this age group who did not meet FGS recommendations and who consumed an average of 1.06 ⫾ 0.02 servings of dairy per day (p ⬍ 0.05). The median potassium intake for this age group of adults who met FGS dairy
Table 4. Impact of Various Levels of Dairy Consumption on Potassium Intake - NHANES 1999 –2002 Number of Dairy Servings Consumed per Day
Children 2–8 Years Number of subjects Potassium Mean, mg/daya Potassium Median, mg/day Potassium, % meeting AI2 Dairy Consumption, servings/day1a Children 9–18 Years Number of subjects Potassium, mg/daya Potassium Median, mg/day Potassium, % meeting AI Dairy Consumption, servings/daya Adults 19–50 Years Number of subjects Potassium, mg/daya Potassium Median, mg/day Potassium, % meeting AI Dairy Consumption, servings/daya Adults 51⫹ Years Number of subjects Potassium, mg/daya Potassium Mean, mg/day Potassium, % meeting AI Dairy Consumption, servings/daya
1 to 1.5
1.5 to 2.5
2.5 to 3.5
3.5 to 4.5
619 1447 (42)1 1362 (33)1 1.2 0.8 (0.02)
434 1793 (49) 1674 (49) 2.8 1.24 (0.01)
714 2040 (39) 1960 (32) 2.9 1.98 (0.02)
415 2483 (39) 2380 (69)) 8.6 2.91 (0.02)
221 2705 (70) 2572 (74) 15.8 3.91 (0.03
168 3459 (89) 3299 (90) 43.3 5.76 (0.13)
1704 1744 (39) 1550 (31) 1.4 0.47 (0.01)
804 1971 (47) 1727 (37) 3.0 1.22 (0.01)
1131 2267 (36) 2070 (31) 3.2 1.96 (0.0)
655 2827 (71) 2598 (57) 6.0 2.94 (0.01)
351 3039 (91) 2867 (76) 8.7 3.95 (0.0)
343 4201 (98) 3843 (110) 33.5 6.27 (0.16)
2282 2228 (35) 2041 (35) 4.3 0.36 (0.01)
656 2638 (47) 2495 (69) 4.8 1.23 (0.01)
872 2967 (60) 2754 (64) 7.9 1.94 (0.01)
440 3226 (87) 3027 (99) 10.6 2.94 (0.02)
214 3781 (88) 3571 (99) 20.6 3.95 (0.02)
259 4588 (134) 4267 (129) 38.5 6.43 (0.2)
2168 2285 (39) 2117 (41) 3.6 .036 (0.01)
687 2750 (43) 2662 (74) 5.7 1.23 (0.01)
677 2957 (59) 2848 (69) 5.8 1.96 (0.01)
321 3394 (95) 3143 (79) 12.5 2.90 (0.02)
138 3769 (128) 3642 (155) 17.6 3.90 (0.03)
115 4685 (181) 4155 (192) 39.8 6.04 (0.21)
(SEM). AI ⫽ Adequate Intake. a p-value for trend statistically significant, p ⬍ 0.05. 2
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Contribution of Dairy Products to Dietary Potassium Intake and median potassium intakes increased significantly for all subjects with increasing dairy consumption (p-value for trend was significant for an increased potassium intake as dairy servings increased). Even at the highest dairy servings intake (⬎4.5 servings per day) less than 50% of children ages 2 to 18 met the potassium AI for their respective age. For adults who consumed the highest level of dairy servings per day less than 40% met the adult AI for potassium (Table 4).
DISCUSSION Based on our analysis of the NHANES 1999 –2002 dietary data potassium intake was inadequate for a large proportion of the US population. Increased consumption of dairy products had a significant positive impact on potassium intake for all age groups. However, mean potassium intakes did not meet the potassium AI for any of the age groups analyzed. Since the mean potassium intake for all age groups was below the AI, it cannot be concluded that the prevalence of inadequate potassium intake in the population is low . These data suggest that for all age groups the intake of dietary potassium in the US population is suboptimal. One strength of our analyses is the use of a large nationally representative dietary survey. The dietary data used in these analyses were obtained from a single 24-hour dietary recall, a method that has been reported to provide valid estimates of mean and median intakes of nutrients in populations . Low intakes of potassium have been reported previously for the US population [1,4,16]. Ervin et al.  reported a mean potassium intake for all ages of 2,628 ⫾ 30 mg/day and a median of 2,422 mg/day from the 1999 –2000 NHANES data. This is similar to the mean and median potassium intakes reported for all age groups in Table 3 and significantly below the potassium AI for all age groups. An inadequate potassium intake by a large proportion of the US population is of concern. Increased dietary potassium intake is associated with decreased risk of high blood pressure and stroke, leading causes of morbidity and mortality in the US [1,4,5]. Diets that provide an increased potassium intake from dairy products, fruits and vegetables have been shown to significantly decrease blood pressure and risk of stroke [7,17,18]. Additionally the sodium content of fluid milk is low and it qualifies as a low-sodium food (⬍ 140 mg per reference serving) . The DASH dietary pattern recommends eight to 10 servings of fruits and vegetables, two to three servings of low-fat dairy products, seven to eight servings of grains (preferably whole grains) and two or less servings of meats, poultry and fish per day [19,20]. Since our analysis demonstrates an inadequate intake of potassium in age groups as young as 2 to 8 years, it raises the concern of the potential life-long health implications of suboptimal potassium intake. Our analysis also demonstrates the inadequate dietary potassium intake of US adults, in particular those over age 50, who are the group at increased risk for hypertension and stroke
. It has been recommended that dietary potassium intakes be increased among older adults and ethnic groups who are at increased risk of hypertension [21,22]. Our results also highlight the important contribution of dairy products to dietary potassium intake. Dietary potassium intake increased for all age groups as dairy consumption increased. The 2005 Dietary Guidelines highlight the importance of dairy products to overall diet quality and adequate nutrient intake . For all age groups the mean dietary potassium intake was significantly greater for the subjects who met or exceeded FGS dairy consumption recommendations compared to those who did not. However, less than 50% of any age group analyzed met the FGS dairy recommendations. Adults had the lowest percentage of individuals meeting the FGS dairy recommendations with only 16.1% of adults 19 to 50 years and 10.7% of those age 51⫹ meeting the dairy intake recommendations. Ranganathan et al.  reported increasing potassium intakes with increased dairy consumption in the Bogalusa Heart study. They also reported that 48% of adults consumed one serving or less of dairy products per day . In our analysis adults age 19 and older who did not meet FGS dairy consumption recommendations consumed an average of one serving of dairy per day. Even when any of the age groups in our analysis consumed the FGS recommended amount of dairy products, mean potassium intakes were suboptimal when compared to the respective potassium AI. This highlights the importance of increasing potassium intake by increasing consumption of a variety of potassium-rich foods including fruits, vegetables, whole grains, nuts, seeds and dried beans along with consuming the recommended number of dairy servings per day. The most recent Dietary Guidelines for Americans 2005  emphasize the importance of consuming potassium-rich foods such as fruits, vegetables and low-fat dairy products. The 2005 version of the FGS, which includes MyPyramid, includes an increase in the number of recommended dairy servings for adults from two servings to three servings per day . In 2004 the Food and Nutrition Board set the AI for potassium at higher levels than had been previously recommended with an AI for adults of 4700 mg/day due in part to the role of dietary potassium in reducing risk of CVD and other chronic disease [12,24,25]. Our analysis suggests that consumption of a variety of food groups that are potassium-rich is important for all age groups to help meet the current AI intake recommendations. The low percentage of subjects in these analyses who met FGS dairy intake recommendations raises the concern of adequate intake of other nutrients provided by dairy products, in particular calcium, vitamin D, phosphorus and magnesium. An analysis of data from the Continuing Survey of Food Intake by Individuals 1994 –96, 1998 (CSFII) and NHANES 1999 –2000 demonstrated that children and adults who met or exceeded dairy intake recommendations were more likely to have a mean calcium intake that meets the age appropriate calcium AI . Moreover, several of the food groups that are good sources of
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Contribution of Dairy Products to Dietary Potassium Intake potassium are also good sources of magnesium including green vegetables, nuts, legumes and whole grains . Inadequate intake of dietary magnesium for a large portion of the US population has previously been reported using an analysis of NHANES 1999 –2000 data . Information about the potassium content of labeled foods is often lacking since potassium is not a mandatory component of nutrition labeling in the US . In addition, there may be consumer confusion even when foods are labeled with potassium content. The Daily Value used for nutrition labeling in the US is currently set at 3500 mg which is significantly lower than the 2004 AI of 4700 mg/day for adults [3,12]. Current US labeling regulations that do not require mandatory labeling of potassium content should be reconsidered in light of the fact that the FDA allows a health claim on food labels linking diets containing foods that are good sources of potassium to reduced risk of high blood pressure and stroke [5,6].
CONCLUSIONS Consumption of dairy products is below current recommendations which in part contributes to suboptimal dietary potassium intakes among a large proportion of the US population. Dairy products make a significant contribution to dietary potassium intake for all age groups however potassium intakes were below the current age-appropriate AI even for those who met dairy intake recommendations. Consumption of potassiumrich foods, such as low-fat and fat free dairy products, fruits, vegetables, legumes and whole grains are emphasized in the most recent Dietary Guidelines 2005 and should continue to be encouraged. The food labeling policy that does not include potassium content as part of mandatory nutrition labeling in the US should be reconsidered. Since adequate potassium intake is associated with decreased risk of chronic disease, in particular CVD, education programs about the health benefits of adequate potassium intake should be an important public health effort.
This work was supported by the National Dairy Council, Rosemont, IL. 17.
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Contribution of Dairy Products to Dietary Potassium Intake 20. Appel LJ: Lifestyle modification as a means to prevent and treat high blood pressure. J Am Soc Nephrol 14(7 Suppl 2):S99–S102, 2003. 21. Lancaster KJ, Smiciklas-Wright H, Weitzel LB, Mitchell DC, Friedmann JM, Jensen GL: Hypertension-related dietary patterns of rural older adults. Prev Med 38:812–818, 2004. 22. Douglas JG: Clinical guidelines for the treatment of hypertension in African Americans. Am J Cardiovasc Drugs 5:1–6, 2005. 23. Ranganathan R, Nicklas TA, Yang SJ, Berenson GS: The nutritional impact of dairy product consumption on dietary intakes of adults (1995–1996): the Bogalusa Heart Study. J Am Diet Assoc 105:1391–1400, 2005. 24. Nieves JW: Osteoporosis: the role of micronutrients. Am J Clin Nutr 81:1232S–1239S, 2005.
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Received July 26, 2005; Accepted March 18, 2007.
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