SODIUM, POTASSIUM, AND HIGH BLOOD PRESSURE Learning Objectives

SODIUM, POTASSIUM,
AND HIGH BLOOD
PRESSURE
by Thomas P. Martin, Ph.D., FACSM, RCEP and Anastasia N. Fischer, M.D.
Learning Objectives
• Highlight evidence documenting effect of high sodium intake on
high blood pressure and risk of cardiovascular disease
• Learn potential impact of reduction in sodium intake on health
care costs
• Appreciate the sodium-potassium connection and how potassium
intake can blunt the effects of sodium on high blood pressure
• Present strategies for reducing sodium and increasing potassium
intake in the American population
• Familiarization with dietary reference intakes
Key words:
Salt, Dietary Reference Intakes, Health Care Costs, Cardiovascular
Disease, Nutrition
INTRODUCTION
T
he purpose of this article is to review the
importance of both sodium and potassium for normal body function as well as
evidence that indicates excess sodium and inadequate potassium are both directly related to
high blood pressure and the potential for subsequent cardiovascular disease. Recommendations/
strategies are presented to address the overconsumption of sodium and underconsumption
of potassium in the American diet.
(HBP) or hypertension is defined as a systolic
reading greater than 140 mmHg or a diastolic
reading greater than 90 mmHg (stage 1). Stage 2
and hypertensive crisis blood pressures also have
been identified (Table 1) (1).
Approximately 73 million Americans, or one
in three adults, have HBP (17). Another 59 million have prehypertension (9). However, because
HBP is an asymptomatic disease, the number is
likely much higher. Adults older than 50 have a
90% lifetime risk of becoming hypertensive (32).
Furthermore, it is estimated that 65% of those
with diagnosed HBP do not have it under
control (10). Consequently, there are millions
of Americans at risk for serious health problems
related to their HBP.
The health consequences of HBP are significant and include damage to the heart and coronary
arteries, stroke, kidney damage, vision loss, and
erectile dysfunction. HBP is known as the Bsilent
killer’’ because there are no warning signs or
symptoms. People often do not realize they have
it until they suffer from a related condition.
Seventy-seven percent of first-time stroke victims,
HIGH BLOOD PRESSURE
The American Heart Association defines normal
blood pressure as a systolic reading less than
120 mmHg and a diastolic reading less than
80 mmHg. Prehypertension is defined as a systolic reading of 120 to 139 mmHg or a diastolic
reading of 80 to 90 mmHg. High blood pressure
VOL. 16/ NO. 3
ACSM’s HEALTH & FITNESS JOURNALA
13
Sodium, Potassium, and High Blood Pressure
TABLE 1: Blood Pressure Categories
and Definitions
Blood Pressure
Category
Normal
Systolic mmHg
(upper no.)
Diastolic mmHg
(lower no.)
less than 120
and
less than 80
Prehypertension
120 to 139
or
80 to 90
HBP (hypertension)
Stage 1
140 to 159
or
90 to 99
HBP (hypertension)
Stage 2
160 or higher
or
100 or higher
Hypertension crisis
(emergency care
needed)
Higher than 180
or
Higher than 110
American Heart Association (1).
69% of first-time heart attack victims, and 74% of firsttime congestive heart failure victims have blood pressure above
140/90 mmHg (2).
HBP was responsible for approximately one in six adult deaths
in the United States in 2005. It was the largest single risk factor for
cardiovascular disease mortality, accounting for approximately
45% of all cardiovascular deaths (14). Based on data from the
U.S. Centers for Disease Control and Prevention (CDC) and the
National Heart, Lung, and Blood Institute, the death rate from
HBP increased by 25%, and the actual number of deaths rose by
56% from 1995 to 2005 (18). The direct and indirect costs of
hypertension were estimated to be $73.4 billion in 2009 (15).
When HBP is confirmed in a patient, the first approach usually
is to prescribe dietary changes that will result in reduced sodium
consumption. If after 3 to 6 months, the patient returns and blood
pressure remains high, then a first-order control medication
(e.g., diuretic) is typically prescribed. The standard diuretic acts
to reduce fluid volume, and in the process, both sodium and
potassium are excreted in the urine. The loss of potassium can
result in hypokalemia (insufficient potassium) with resultant
muscle weakness, irregular heart rhythm, confusion, and increased salt sensitivity. This is why the patient starting a diuretic
medication is advised to increase potassium consumption or take
a potassium supplement.
Many factors are known to influence and affect blood pressure:
genetics (family history), excessive alcohol consumption, sex,
age, body composition, physical activity (exercise), medical conditions, stress, smoking, and diet. This article addresses one aspect of diet, the impact of sodium and potassium intake on blood
pressure, and the risk of cardiovascular disease.
minerals that have been identified as micronutrients essential for
normal body function. They are called micronutrients because
they are needed by the body in small amounts (mg to Hg).
Sodium and potassium are two of these minerals; they are
essential for water balance, transmission of nerve impulses, and
contraction/relaxation of muscle.
Four categories of DRIs serve as important references for
micronutrient consumption. The first is the recommended dietary
allowance (RDA). This is the amount of a micronutrient, determined by sex and age, which is necessary to prevent a deficiency.
RDAs are established to cover 98.75% of the population. The
second is adequate intake (AI), which is used when an RDA has
not been determined. AIs are believed to cover the needs of
all individuals in an age/gender group, but lack of data or
uncertainty in the data prevent being able to specify an RDA. The
third is tolerable upper intake level (UL), which represents the
highest intake that is likely to pose no risk of adverse health
effects. The fourth is estimated average requirement. This is the
average daily nutrient intake level estimated to meet the requirements of half of the healthy individuals in an age/sex group.
RDAs, AIs, and ULs are references that are meaningful for the
consumer, whereas estimated average requirements are used primarily by nutrition scientists.
This article will emphasize the UL for sodium and the AI for
potassium. Based on the UL, a high sodium intake is defined as
an intake greater 2,300 mg/day. Based on AI, a low potassium
intake is defined as an intake less than 4,700 mg/day (Table 2).
SODIUM
Dietary Guidelines for Americans 2005 recommended that
sodium consumption be limited to 2,300 mg/day or less. Furthermore, it recommended that individuals with hypertension,
blacks, and middle-aged and older adults consume no more
than 1,500 mg/day. Dietary Guidelines for Americans 2010
(DG 2010) recommends that sodium intake be less than 1,500
mg/day (28). This decrease was based on the statistic that now
nearly 70% of U.S. adults are hypertensive, black, and middleaged or older adults. It is stated that this group would benefit
from reduced sodium consumption. The AI and UL for sodium
are 1,500 and 2,300 mg/day, respectively. These are small
amounts. To put it in perspective, just one teaspoon of table salt
(sodium chloride, NaCl; 40% Na and 60% Cl) contains about
2,300 mg of sodium.
TABLE 2: Adequate Intake and Tolerable
Upper Intake Levels for Sodium and Potassium
DIETARY REFERENCE INTAKES
The Food and Nutrition Board of the National Academy of
Sciences establish dietary reference intakes (DRIs) that are used
as references/guidelines for micronutrient consumption in the
United States (22). There are currently 13 vitamins and 22
14
ACSM’s HEALTH & FITNESS JOURNALA | www.acsm-healthfitness.org
AI (mg/day)
UL (mg/day)
Sodium
1,500
2,300
Potassium
4,700
Not determined
Dietary reference intakes, reference (21).
VOL. 16/ NO. 3
Potential Consequences of High Sodium Intake
It has been well documented that high sodium can trigger increased sodium retention, which can result in increased fluid
volume and HBP. HBP is directly related to the risk of heart
disease and stroke (30). Other potential negative effects of excess sodium consumption include the following:
• increased calcium excretion (27,28)
•
kidney damage (12,28,33)
•
atherosclerosis/arteriosclerosis (11,12)
•
left ventricular hypertrophy (17,28)
•
increased incidence of gastric cancer (28)
•
increased risk of dementia (7)
Negative Impact of Sodium Questioned
A recent article titled BIt’s Time to End the War on Salt,’’ makes the
argument that the recommendation to limit salt intact has little
basis in science (20). The article related the results of select
studies that found little or no relationship between salt intake,
high blood pressure, risk of cardiovascular disease, and death.
One study that the article’s authors highlighted to support their
argument was a meta-analysis of seven studies that found no
strong evidence between reducing salt and the risk of cardiovascular events (26). This study, and others presented to support
the contention that there is little evidence to support a national
effort to reduce sodium in the United States, was challenged in
a recent professional commentary. Contrary to the original evaluation, He and MacGregor (13) reanalyzed the seven studies of
the meta-analysis and found that they actually supported current
health recommendations to reduce salt intake. The authors state
that the substantial benefits in reducing the average intake of salt
are supported by extensive evidence, including epidemiological
studies, animal studies, randomized trials, and outcome studies.
Furthermore, it should be recognized that the DG 2010 recommendation to reduce sodium intake is based on a far-reaching
body of research that supports that recommendation. The population sodium reduction recommendation is supported by numerous professional organizations and associations, including
the American Heart Association, the American Society of Hypertension, and the World Health Organization (28).
classify individuals (authors’ emphasis) as salt sensitive or not
(28, p. 334).’’ At the same time, it is meaningful to examine
sodium sensitivity in these subgroups of the population. These
subgroups, in combination, comprise the vast majority of the
adult population in the United States. Therefore, the doseresponse relationship between sodium intake and blood pressure
is important on the population level. Furthermore, the potential
negative consequences of high sodium intake (beyond HBP)
outlined above indicate that all individuals should be concerned
with sodium consumption.
Consumption of Sodium in the United States
The National Health and Nutrition Examination Survey is
conducted by the National Center for Health Statistics, which is
part of the CDC. A recent analysis of the 2005Y2008 data from
the National Health and Nutrition Examination Survey divided
the U.S. population into two groups based on the sodium recommendations of the DG 2010. Group 1 consisted of those who
would benefit from reducing sodium intake to less than 1,500
mg/day, that is, persons age 51 years or older; blacks; and
persons with hypertension, diabetes, or chronic kidney disease.
Group 2 consisted of those who should limit sodium intake to
less than 2,300 mg/day (everyone else). The average sodium
consumption of group 1 was 3,264 mg/day, and that of group 2
was 3,513 mg/day. Furthermore, 98.6% of group 1 and 88.2%
of group 2 exceeded guidelines (6). A Healthy People 2020 goal
is to reduce average consumption of sodium to 2,300 mg/day
by the year 2020 (30).
Americans have found it difficult to reduce salt intake. This is
primarily due to Baway-from-home’’ food intake and the consumption of processed foods. Away-from-home foods include
meals and ready-to-eat items purchased at restaurants, preparedfood counters at grocery stores, and other outlets. The restaurant
industry share of the food dollar has increased dramatically over the
past 50 years and is currently at 49% of the total food budget (21).
In general, fast food and restaurant food are high in sodium.
Sodium Sensitivity
Sodium sensitivity means that increased sodium loading will result
in a rise in blood pressure and that decreased sodium intake will
result in a reduction in blood pressure. Evidence from several
studies has demonstrated a varied blood pressure response to sodium intake. For example, those with HBP, diabetes, and chronic
kidney disease; those who are middle- and older-aged persons; and
blacks tend to be more sodium sensitive than younger whites (28).
However, BBecause no standardized diagnostic criteria and tests
exist and blood pressure is highly variable, it is impossible to
VOL. 16/ NO. 3
ACSM’s HEALTH & FITNESS JOURNALA
15
Sodium, Potassium, and High Blood Pressure
Even patients with cardiovascular disease find it difficult to
cut back on salt intake. In a study of 116 people with heart
failure, researchers asked the subjects to write down everything
they ate for 3 days. It was recommended that all patients eat a
low-salt diet. The study found that participants consumed an
average of 2,671 mg/day of sodium (AI is 1,500 mg, and UL is
2,300 mg), and only one third adhered to the recommended
daily sodium intake. Most thought they were taking steps to
reduce their sodium intake by putting less salt on their foods.
What they did not realize is that most sodium comes from
processed and restaurant foods (24).
Why and How Sodium Is Consumed
Salt is a common seasoning in most cultures. It tastes good, has
its own flavor, and also enhances other flavors in food. Salt also
is used as a food preservative, to enhance texture, mask bitterness, and is inexpensive. Therefore, it is not surprising that salt
often is added during food processing.
Major sources of sodium include bakery products (e.g., yeast
breads), chicken and chicken mixed dishes, pizza, pasta and
pasta dishes, processed meats (e.g., cold cuts, bacon, sausage,
and franks), condiments (e.g., ketchup and salad dressing), Mexican
mixed dishes, regular cheese, butter and margarine, grain-based
desserts, soups, beef mixed dishes, canned food, foods with
added external salt (e.g., potato chips and pretzels), pickles, and
soy sauce (Table 3).
Five percent of salt consumption comes from salt added
during cooking, 6% is added at the table, 12% is occurring
naturally in food, and 77% comes from salt that is added during
food processing and at restaurants (19). It is clear that processed
and restaurant food is high in sodium. Consumers need to recognize that fact and also learn to read labels to evaluate the salt
content of food before purchase.
disease by 60,000 to 120,000, stroke by 32,000 to 66,000, and
myocardial infarction by 54,000 to 99,000 cases per year. It was
projected that this sodium reduction would save $10 to $24
billion in health care costs annually. The researchers also stated
that cutting just 1000 mg of salt daily would be more cost
effective than using medication to lower blood pressure in all
persons with hypertension (4).
Recommendations/Strategies for Sodium Reduction in
the United States
According to the 2010 Institute of Medicine (IOM) committee
report on strategies to reduce sodium intake, activities to reduce
sodium intake have been going on in the United States for more
than 40 years but have not succeeded (15). Consumer education,
availability of select lower-sodium and reduced-sodium products, and voluntary reduction in sodium intake have not lowered
overall sodium intake in the United States. Therefore, the report
recommended strategies to further address excess sodium in the
U.S. diet:
Primary Strategy V The establishment of sodium Bsafe
use’’ standards by the Food and Drug Administration (FDA) for
the food industry and restaurant/foodservice operators; these
standards are to be implemented in a step-down fashion to
promote decreasing consumer sensory preference for salt and
industry adaptation. It was stated that BStandards for the addition of salt to processed and restaurant/food service foods are
the best strategy to protect the public health (15, p. 9).’’
Interim Strategy V Food manufacturers and restaurant/
foodservice operators voluntary efforts to reduce sodium in
processed foods and menu items, respectively. The CDC states
that sodium consumption could be reduced by manufacturers
gradually reducing the amount of sodium in their processed and
prepared foods, with little or no behavior change on the part of
the individual consumer (8).
Sodium Consumption and Obesity
One reason for the rise of sodium consumption is related to our
national obesity epidemic. What a person eats is obviously important, but how much they eat also is a concern relative to
sodium intake. Whatever the sodium content of a person’s diet,
if they consume more food, they likely will be consuming more
sodium. Therefore, some sodium reduction can reasonably be
expected with the consumption of fewer total calories.
Health-Care Costs
According to two recent studies, a nationwide reduction in sodium intake would result in a significant decrease in health
care costs. A 2009 study reported that reducing sodium intake
by 1,110 mg/day could reduce hypertension cases by 11.1 million
and result in a $17.8 billion (in 2005 dollars) savings in health care
costs (23). Using predictive modeling, a 2010 study projected
that a population-wide reduction of 1,200 mg/day of sodium
could reduce the annual number of new cases of coronary heart
16
ACSM’s HEALTH & FITNESS JOURNALA | www.acsm-healthfitness.org
Supporting Strategies
•
FDA and U.S. Department of Agriculture (USDA) to revise
and update labeling based on a sodium AI of 1,500 mg/day
and the expansion of these provisions and all labeling provisions to restaurant/foodservice operators, that is, improving
point-of-purchase sodium information
•
leveraging, through government and nongovernment large food
purchases; that is, setting salt specifications for food purchase.
•
promotion by government and nongovernment groups of the
sodium intake goals established by the DG 2010. Also, providing support for consumers in making behavior changes to
reduce sodium intake.
•
Continued and enhanced federal monitoring of sodium
intake, salt taste preference, sodium content of foods, as well
VOL. 16/ NO. 3
TABLE 3: Sodium Content of Selected Foods per Common Measure
Description
Common Measure
Sodium (mg)
1 packet
3,132
Salt, table
1 tsp
2,325
Bread crumbs, dry, grated, seasoned
1 cup
2,111
Soup, onion, dry, mix
Fast food, submarine sandwich, with cold cuts
1 - 6’’ roll
1,651
Wheat flour, white, all-purpose, self-rising, enriched
1 cup
1,588
Potato salad, home-prepared
1 cup
1,323
Fast food, cheeseburger; single, large patty; with condiments and bacon
1 sandwich
1,314
1 cup
1,284
Fast food, taco
1 large
1,233
Fast food, biscuit, with egg and sausage
1 biscuit
1,210
Beans, baked, canned, with franks
1 cup
1,114
Sauce, pasta, spaghetti/marinara, ready-to-serve
1 cup
1,025
Cheese, cottage, low fat, 1% milk fat
1 cup
918
Soy sauce made from soy and wheat (shoyu)
1 tbsp
902
Tomato products, canned, sauce
Beef stew, canned entre´e
Chicken pot pie, frozen entree, prepared
Salami, cooked, beef and pork
Snacks, pretzels, hard, plain, salted
1 cup
900
1 small pie
828
2 slices
822
10 pretzels
814
Macaroni and Cheese, canned entre´e
1 cup
761
Pasta with meatballs in tomato sauce, canned entree
1 cup
733
Fast food, pizza chain, 14’’ pizza, pepperoni topping regular crust
1 slice
670
Pickles, cucumber, dill or kosher dill
1 pickle
569
Bagels, egg
4’’ bagel
449
Waffles, plain, prepared from recipe
1 waffle
383
Pie, pumpkin, commercially prepared
1 piece
368
Fast food, Danish pastry, fruit
1 pastry
333
Cereals, Quaker, instant oatmeal, maple and brown sugar
1 packet
253
1 oz
248
Cheese, provolone
Snacks, potato chips, barbecue-flavor
Toaster pastries, brown-sugar cinnamon
1 oz
213
1 pastry
212
Catsup
1 tbsp
167
Salad dressing, Italian, reduced fat
1 tbsp
161
Candies, Reese’s peanut butter cups
1 package (2)
161
1 cup
150
Milk, chocolate, fluid, commercial, whole, with added vitamin A and vitamin D
Sauce, barbecue
1 tbsp
133
Margarine-like, vegetable oil spread, 60% fat, stick with salt
1 tbsp
112
Butter, salted
1 tbsp
101
USDA National Nutrient Database, Nutrient Lists, Sodium; www.nal.usda.gov/fnic/foodcomp/search.
as population knowledge, attitudes, and behavior related to
sodium.
•
Public-private partnerships to encourage consumers to take
personal responsibility and action to reduce salt intake.
The USDA has recently proposed new guidelines for school
breakfasts and lunches subsidized by the federal government.
VOL. 16/ NO. 3
These guidelines would require schools to cut sodium in meals
by more than a half. They also would require that schools use
only whole grains and serve low-fat milk. In addition, standards
call for more whole fruits and vegetables and only one cup of
starchy vegetables (29). The IOM has emphasized that the early
stages of blood pressure-related atherosclerotic disease begin
during childhood (28).
ACSM’s HEALTH & FITNESS JOURNALA
17
Sodium, Potassium, and High Blood Pressure
POTASSIUM
Potassium is necessary for water balance, transmission of nerve
impulses, maintenance of heart beat (rhythm), and muscle contraction. The AI for potassium is 4,700 mg/day, that is, more
than three times the AI for sodium (1,500 mg/day). The CDC
states that Americans should consume more potassium-rich
foods to meet the recommended AI for potassium (7).
Consumption of Potassium in the United States
DG 2010 reports that the mean intake of potassium is approximately 3,200 mg/day for men and 2,400 mg/day for women
(28). It was reported that less than 5% of Americans had potassium intakes above the AI during 1988Y1994 and that the
number had decreased to 2.4% in 2003Y2004 (25).
A moderate potassium deficiency is characterized by increased
blood pressure, increased risk of kidney stones, increased urinary
excretion of calcium, and salt sensitivity (16). Potassium blunts
the effects of sodium and is therefore important in the control of
blood pressure (3). A dietary practice to lower blood pressure is
to consume a diet rich in potassium (25).
Good Sources of Potassium
Good sources of potassium include fruit, vegetables, legumes,
juices, meat, fish, and dairy products (Table 4).
A UL for potassium has not been established because it
is virtually impossible to overdose on potassium from natural
sources. However, it is possible to overdose on potassium by
taking over-the-counter and/or prescription supplements. Older
adults are at increased risk of potassium overload as a result of
certain medical conditions, for example, diabetes, kidney disease,
heart failure, and adrenal insufficiency. In addition, individuals
taking medications, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and potassium-sparing
diuretics, which can impair potassium excretion, should monitor
their potassium consumption particularly from salt substitutes and
supplements (28).
Mortality File (1988Y2006), a nationally representative sample
of 12,267 adults, to study all-cause, cardiovascular, and ischemic
heart diseases mortality. The authors used mean sodium intake
(mg/day) divided by mean potassium intake (mg/day) and found
that a higher sodium-potassium ratio was associated with significantly increased risk of CVD and all-cause mortality. Furthermore, the findings did not differ significantly by sex, race/
ethnicity, body mass index, hypertension status, education levels,
or physical activity. The combination of high sodium and low
potassium showed a stronger risk for CVD and death than each
mineral alone.
The AI for sodium is 1,500 mg. The AI for potassium is
4,700 mg. Therefore, the AI sodium/potassium ratio is 1 mg of
sodium to 3 mg of potassium (0.32). It seems that the importance of adequate potassium intake and its influence on blood
pressure has been underappreciated. Furthermore, the sodiumpotassium ratio seems to hold promise as a valuable reference
related to risk of disease.
Suggestions for Potassium Increase in the
United States
It is suggested that Americans adjust their diets to include more
natural sources of potassium. Diets with plenty of fruits, vegetables, whole grains, and low-fat dairy are recommended for
heart health. One example is the Dietary Approaches to Stop
Hypertension (DASH) diet (5). The DASH diet is rich in potassium and other minerals while encouraging people to eat less
sodium-laden foods (28,31). It is recommended by the USDA as
an eating plan for all Americans. The plan also emphasizes good
eating habits, discourages processed foods, and suggests alternatives to Bjunk food.’’ The guide, which is available online (31),
provides sample meal plans as well as the nutrition information
on popular food items.
The IOM Committee on Public Health Priorities to Reduce
and Control Hypertension in the U.S. population has suggested
Sodium/Potassium Ratio
The intake of sodium and potassium and the function of these
minerals in the body are related. For example, the sodiumpotassium pumps actively serve to maintain water balance
between the intracellular and extracellular fluids. About two thirds
of body water is intracellular, and one third is extracellular (e.g.,
blood plasma and interstitial fluid). Potassium is the main electrolyte in the intracellular fluid, and sodium is the main electrolyte in the extracellular fluid. Both a high sodium intake and
a low potassium intake have been linked to HBP. Deductive
reasoning supports the hypothesis that the sodium/potassium ratio also is linked to HBP.
This theory is supported by a recent study that specifically
examined the sodium/potassium ratio (34). This study utilized the
Third National Health and Nutrition Examination Survey Linked
18
ACSM’s HEALTH & FITNESS JOURNALA | www.acsm-healthfitness.org
VOL. 16/ NO. 3
TABLE 4: Potassium Content of Selected Foods per Common Measure
Description
Common Measure
Potassium (mg)
1 cup
1,086
1 potato
1,081
Raisins, seedless
Potato, baked, flesh and skin, without salt
Soybeans, mature cooked, boiled, without salt
Fish, halibut, Atlantic and Pacific, cooked, dry heat
1 cup
886
½ fillet
840
Spinach, cooked, boiled, drained, without salt
1 cup
839
Beans, kidney, red, mature seeds, cooked, boiled, without salt
1 cup
713
Sweet potato, cooked, baked in skin, without salt
1 potato
694
Fish, salmon, sockeye, cooked, dry heat
½ fillet
632
8-oz container
579
Yogurt, plain, skim milk, 13 g protein per 8 oz
Spinach, frozen, chopped or leaf, cooked boiled, drained, without salt
1 cup
574
Orange juice, raw
1 cup
496
Melons, cantaloupe, raw
Bananas, raw
Turkey, all classes, meat only, cooked, roasted
Apricots, dried, sulfured, uncooked
1 cup
427
1 banana
422
1 cup
417
10 halves
407
Grapefruit juice, white, raw
1 cup
400
Peas, edible-podded, boiled, drained, without salt
1 cup
384
Corn, sweet, yellow, frozen, kernels cut off cob, boiled, drained, without salt
1 cup
382
2 slices
368
Milk, low fat, fluid, 1% milk fat, with added vitamin A and vitamin D
1 cup
366
Carrots, raw
1 cup
352
Ham, sliced, extra lean
Beef, top sirloin, steak, lean only, trimmed to 1/8’’ fat, all grades, cooked, broiled
3 oz
320
Peppers, sweet, red, raw
1 cup
314
Grapes, red or green, raw
Tomatoes, red, ripe, raw, year round average
Broccoli, raw
1 cup
306
1 tomato
292
1 cup
278
Dates, Deglet Noor
5 dates
272
Strawberries, raw
1 cup
254
Onions, raw
1 cup
234
Chicken, broilers or fryers, breast, meat only, cooked, roasted
½ breast
220
1 oz (24 nuts)
200
Peanuts, all types, dry-roasted, without salt
1 oz
187
Watermelon, raw
1 cup
170
Wild rice, cooked
1 cup
166
Cucumber, peeled, raw
1 cup
162
Apples, raw, with skin
1 apple
148
1 cup
138
Nuts, almonds
Lettuce, cos or romaine, raw
USDA National Nutrient Database, Nutrient Lists, Potassium; www.nal.usda.gov/fnic/foodcomp/search.
a strategy of using Bmodified salt’’ in food preparation, in which
part of the sodium chloride is replaced by potassium chloride.
This would both increase potassium consumption and decrease
sodium consumption. Those individuals for whom additional
potassium is not advisable would be informed of the potassium
content by appropriate labeling of products (14).
VOL. 16/ NO. 3
The FDA requires that vitamin A, vitamin C, calcium, and
iron percent daily values (%DV) appear on the Nutrition Facts
panel of labeled foods. This requirement is based on data that
indicate that the average American diet is deficient in these
micronutrients and that increased consumption could reduce the
risk of related diseases. The American diet also is deficient in
ACSM’s HEALTH & FITNESS JOURNALA
19
Sodium, Potassium, and High Blood Pressure
potassium (25). There are at least three reasons why the FDA
should require that a listing of potassium content in milligrams
and %DV appear on the Nutrition Facts panel: it would alert
consumers to the importance of potassium in a healthful diet;
it would permit an easy comparison between sodium and potassium content; and increased potassium intake, along with
decreased sodium intake, could result in a decreased risk of
cardiovascular disease.
As with sodium, efforts to achieve the AI for potassium across
the U.S. population will require nutritional education, individual
commitment, government support, and the cooperation of the
food industry.
We are just beginning to learn and understand the influence
and interaction of single nutrients on each other and on body
function. For example, vitamin D is important for the absorption of calcium, and vitamin C assists in the absorption of iron.
Evidence suggests that sodium and potassium work together for
water balance and, together, affect blood pressure as well as risk
of disease.
SUMMARY
Dietary consumption of sodium and potassium has been implicated in control of blood pressure. Reducing the amount of
processed and prepared foods in the diet will address excess
sodium consumption, whereas increasing the consumption of
foods high in potassium may help temper sodium excess and
promote normotension. Evidence suggests that these changes
would lower the prevalence of hypertension and the risk of cardiovascular and other comorbid diseases and result in reduced
health care costs.
References
1. American Heart Association Web site [Internet]. Understanding
blood pressure readings. [cited 2011 November 20]. Available from:
http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/
AboutHighBloodPressure/Understanding-Blood-Pressure-Readings_
UCM_301764_Article.jsp.
2. American Heart Association Web site [Internet]. Why blood pressure
matters. [cited 2011 November 20]. Available from: http://www.heart.org/
HEARTORG/Conditions/HighBloodPressure/WhyBloodPressureMatters/
Why-Blood-Pressure-Matters_UCM_002051_Article.jsp.
3. American Heart Association Web site [Internet]. Potassium and
high blood pressure. [cited 2011 November 20]. Available from:
http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/
PreventionTreatmentofHighBloodPressure/Potassium-and-High-BloodPressure_UCM_303243_Article.jsp.
4. Bibbins-Domingo K, Chertow GM, Coxson PG, et al. Projected effect of
dietary salt reductions on future cardiovascular disease. N Engl J Med.
2010;362:590Y9.
5. Bray GA, Vollmer WM, Sacks FM, et al. DASH Collaborative Research
Group. A further subgroup analysis of the effects of DASH diet and three
dietary sodium levels on blood pressure: results of the DASH-Sodium
Trial. Am J Cardiol. 2004;94(2):222Y7.
6. Centers for Disease Control and Prevention. Usual sodium intakes
20
ACSM’s HEALTH & FITNESS JOURNALA | www.acsm-healthfitness.org
compared with current dietary guidelines V United States, 2005Y2008.
MMWR Morb Mortal Wkly Rep. 2011;60(41):1413Y7.
7. Centers for Disease Control and Prevention Web site [Internet]. Most
Americans should consume less sodium. [cited 2011 November 20].
Available from: http://www.cdc.gov/salt/.
8. Centers for Disease Control and Prevention Web site [Internet]. Sodium:
the facts. [cited 2011 November 20]. Available from: http://www.cdc.
gov/salt/pdfs/Sodium_Fact_Sheet.pdf.
9. Chobanian AV, Bakris GL, Black HR, et al. The seventh report of
the joint national committee on prevention, detection, evaluation, and
treatment of high blood pressure: The JNC 7 report. JAMA. 2003;
289(19):2560Y72.
10. Chobanian AV. The hypertension paradox V more uncontrolled disease
despite improved therapy. N Eng J Med. 2009;361:878Y87.
11. Dickinson KM, Keogh JB, Clifton PM. Effects of a low-salt diet
on flow-mediated dilatation in humans. Am J Clin Nutr. 2009;89:
485Y90.
12. He FJ, Marciniak M, Visagie E, et al. Effect of modest salt
reduction on blood pressure, urinary albumin, and pulse wave velocity
in White, Black, and Asian mild hypertensives. Hypertension. 2009;
54(3):482Y8.
13. He FJ, MacGregor GA. Salt reduction lowers cardiovascular risk:
meta-analysis of outcome trials. Lancet. 2011;378(9789):380Y2.
14. Institute of Medicine. A Population-Based Policy and Systems Change
Approach to Prevent and Control Hypertension. Washington (DC):
National Academies Press; 2010. 236 p.
15. Institute of Medicine. Strategies to Reduce Sodium Intake in the United
States. Washington (DC): National Academies Press; 2010. 506 p.
16. Institute of Medicine. Dietary Reference Intakes for Water, Potassium,
Sodium, Chloride, and Sulfate. Washington (DC): National Academies
Press; 2005. 640 p.
17. Liebson PR, Grandits G, Prineas R, et al. Echocardiographic correlates of
left ventricular structure among 844 mildly hypertensive men and women
in the Treatment of Mild Hypertension Study (TOMHS). Circulation.
1993;87:476Y86.
18. Lloyd-Jones D, Adams R, Carnethon M, et al. Heart disease and
stroke statistics V 2009 update: a report from the American Heart
Association Statistics Committee and Stroke Statistics Subcommittee.
Circulation. 2009;119(3):480Y6.
19. Mattes RD, Donnelly D. Relative contributions of dietary sodium
sources. J Am Coll Nutr. 1991;10(4):383Y93.
20. Moyer MW. It’s time to end the war on salt. Scientific American, July 8,
2011 [cited 2011 November 20]. Available from: http://www.
scientificamerican.com/article.cfm?id=its-time-to-end-the-war-on-salt.
21. National Restaurant Association Web site [Internet]. Facts at a
glance: 2011 restaurant industry overview. [cited 2011 November 20].
Available from: http://www.restaurant.org/research/facts.
22. Otten JJ, Hellwig JP, Meyers LD, editors. Dietary Reference Intakes: The
Essential Guide to Nutrient Requirements. Washington (DC): National
Academies Press; 2006. 560 p.
23. Palar K, Sturm R. Potential societal savings from reduced sodium
consumption in the U.S. adult population. Am J Health Prom.
2009;24(1):49Y57.
24. Reilly CM, Frediani J, Clark P, et al. Heart failure patients may have
trouble following low-sodium diets, paper presented at the American
Heart Association’s 10th Scientific Forum on Quality of Care and
Outcomes Research in Cardiovascular Disease and Stroke. Washington
DC, April 25, 2009, abstract 235.
25. Sondik EJ. Focus area 19: nutrition and overweight progress review.
National Center for Health Statistics, April 3, 2008. [cited 2011
VOL. 16/ NO. 3
November 20]. Available from: http://www.cdc.gov/nchs/healthy_
people/hp2010/focus_areas/fa19_nutrition2.htm.
26. Taylor RS, Ashton KE, Moxham T, Hooper L, Ebrahim S. Reduced
dietary salt for the prevention of cardiovascular disease: a meta-analysis
of randomized controlled trials (Cochrane Review). Am J Hypertens.
2011;24:843Y53.
27. Teucher B, Dainty JR, Spinks CA, et al. Sodium and bone health:
impact of moderately high and low salt intakes on calcium metabolism
in postmenopausal women. J Bone and Miner Res. 2008;23(9):
1477Y85.
28. U.S. Department of Agriculture. Report of the Dietary Guidelines
Advisory Committee on the Dietary Guidelines for Americans, 2010.
Beltsville, MD: USDA; May 2010, p. 445. Available from: http://www.
cnpp.usda.gov/DGAs2010-DGACReport.htm.
29. U.S. Department of Agriculture. USDA unveils critical upgrades to
nutritional standards for school meals. News Release No. 0010.11,
January 13, 2010. Available from: http://www.usda.gov.
30. U.S. Department of Health and Human Services. Healthy People 2020.
Nutrition and Weight Status, NWS-19. Washington D.C.: U.S. Government
Printing Office; 2010. Available from: http://www.healthypeople.gov.
31. U.S. Department of Health and Human Services, National Institutes of
Health, National Heart, Lung, and Blood Institute. DASH eating plan:
Lower your blood pressure. NIH publication No. 06-4082; 1998, revised
April 2006, p. 56. Available from: http://www.nhlbi.nih.gov/health/
public/heart/hbp/dash/new_dash.pdf.
32. Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for
developing hypertension in middle-aged women and men: the
Framingham Heart Study. JAMA. 2002;287(8):1003Y10.
33. Verhave JC, Hillege HL, Burgerhof JGM, et al. Sodium intake affects
urinary albumin excretion especially in overweight subjects. J Intern
Med. 2004;256:324Y30.
34. Yang Q, Liu T, Kuklina EV, et al. Sodium and potassium intake and
mortality among US adults: prospective data from the Third National
Health and Nutrition Examination Survey. Arch Intern Med.
2011;171(13):1183Y91.
Thomas P. Martin, Ph.D., FACSM, RCEP,
is a professor in the Health, Fitness, and
Sport Department, Wittenberg University,
Springfield, OH. He serves as an expert in
the areas of energy metabolism/nutrition,
body composition, and weight management in ACSM’s media referral program.
Dr. Martin is ACSM Exercise Test TechnologistÒ certified and
ACSM Registered Clinical Exercise PhysiologistÒ certified. His
Web site is www.wittenberg.edu/~tmartin.
Anastasia N. Fischer, M.D., is an assistant
clinical professor of Pediatrics in the Division of Sports Medicine at The Ohio State
University College of Medicine and Nationwide Children’s Hospital in Columbus, OH.
She is a certified family practitioner and
active member of the American Academy of
Family Physicians, American Medical Society of Sports Medicine,
and ACSM, where she is on the Board of Directors of the Midwest
Regional Chapter.
CONDENSED VERSION AND BOTTOM LINE
High sodium and low potassium intakes are related to HBP
and cardiovascular disease. Most Americans are overconsuming
sodium and underconsuming potassium. Recommendations/
strategies are presented for the reduction of sodium consumption. It is suggested that increased potassium intake be
encouraged along with sodium reduction to address the imbalance of these minerals in the typical American diet.
Disclosure: The authors declare no conflict of interest and do
not have any financial disclosures.
VOL. 16/ NO. 3
ACSM’s HEALTH & FITNESS JOURNALA
21