Potassium May Be a Senior Citizen’s Best Friend in
Fighting Hypertension-Causing Salt
Seniors trying to lower blood pressure should boost
their intake of potassium, which has the opposite effect to sodium
Jan. 29, 2009 – Many senior citizens struggle in a
battle against high blood pressure and a key goal is to avoid as much
salt as possible, which is challenging because of its wide use in many
foods. There is new hope, however, in research that finds adding more
potassium to the diet can offset the harmful effects of sodium to reduce
the risk of cardiovascular disease.
Aug.
13, 2002 - People with a low amount of potassium in their diet may have an
increased risk of stroke, according to a study published in the August 13
issue of Neurology, the scientific journal of the American Academy of
Neurology. Click
Nearly one in three adult Americans has high blood
pressure, defined as 140/90 mmHg or higher and about 37 percent have
pre-hypertension. Previously, researchers have shown that long-term
interventions to reduce sodium intake in participants with
prehypertension can lower blood pressure and reduce the risk of
cardiovascular disease.
Most people now know that too much sodium from
foods can increase blood pressure but many are not aware that potassium
as the opposite effect to sodium.
Researchers in this study found that the ratio of
sodium-to-potassium in subjects' urine was a much stronger predictor of
cardiovascular disease than sodium or potassium alone.
"There isn't as much focus on potassium, but
potassium seems to be effective in lowering blood pressure and the
combination of a higher intake of potassium and lower consumption of
sodium seems to be more effective than either on its own in reducing the
risk of cardiovascular disease," said Dr. Paul Whelton, senior author of
the study in the January 2009 issue of the Archives of Internal
Medicine.
Whelton is an epidemiologist and president and CEO
of Loyola University Health System.
Researchers determined average sodium and potassium
intake during two phases of a study known as the Trials of Hypertension
Prevention (TOHP). They collected 24-hour urine samples intermittently
during an 18-month period in one trial and during a 36-month period in a
second trial.
The 2,974 study participants initially aged
30-to-54 and with blood pressure readings just under levels considered
high, were followed for 10-15 years to see if they would develop
cardiovascular disease. Whelton was national chair of the TOHP.
Those with the highest sodium levels in their urine
were 20 percent more likely to suffer strokes, heart attacks or other
forms of cardiovascular disease compared with their counterparts with
the lowest sodium levels. However this link was not strong enough to be
considered statistically significant.
By contrast, participants with the highest
sodium-to-potassium ratio in urine were 50 percent more likely to
experience cardiovascular disease than those with the lowest
sodium-to-potassium ratios. This link was statistically significant.
Most previous studies of the relationship between
sodium or potassium and cardiovascular disease have had to rely on
people's recall or record of what foods they eat to estimate their level
of sodium consumption. This is a less precise measure of sodium intake
than urine samples. In addition, many have been cross-sectional rather
than follow-up studies.
The new study "is a quantum leap in the quality of
the data compared to what we have had before," Whelton said about the
research funded by the National Heart, Lung, and Blood Institute
(NHLBI), part of the National Institutes of Health.
Whelton was a member of a recent Institute of
Medicine panel that set dietary recommendations for salt and potassium.
The panel said healthy 19-to-50 year-old adults should consume no more
than 2,300 milligrams of sodium per day -- equivalent to one teaspoon of
table salt. More than 95 percent of American men and 75 percent of
American women in this age range exceed this amount.
To lower blood pressure and blunt the effects of
salt, adults should consume 4.7 grams of potassium per day unless they
have a clinical condition or medication need that is a contraindication
to increased potassium intake.
Most American adults aged 31-to-50 consume only
about half as much as recommended in the Institute of Medicine report.
Changes in diet and physical activity should be under the supervision of
a health care professional.
Good potassium sources include fruits, vegetables,
dairy foods and fish. Foods that are especially rich in potassium
include potatoes and sweet potatoes, fat-free milk and yogurt, tuna,
lima beans, bananas, tomato sauce and orange juice. Potassium also is
available in supplements.
Whelton is among the nation's top experts on high
blood pressure. He has published more than 400 papers on the subject,
and has been the principal investigator on more than $100 million of
studies funded by the National Institutes of Health.
The “Joint Effects of Sodium and Potassium Intake
on Subsequent Cardiovascular Disease: The Trials of Hypertension
Prevention (TOHP) Follow-up Study” is published in the January 12, 2009
issue of the Archives of Internal Medicine.
Co-authors of the Archives study include Nancy Cook
(first author), Julie Buring and Dr. Kathryn Rexrode of Brigham and
Women's Hospital; Eva Obarzanek and Dr. Jeffrey Cutler of the National
Heart, Lung and Blood Institute; Dr. Lawrence Appel of Johns Hopkins
University and Shiriki Kumanyika of the University of Pennsylvania.
Sodium and Potassium, Dietary Guidelines for
Americans 2005
On average, the higher an individual's salt (sodium
chloride) intake, the higher an individual's blood pressure.
Nearly all Americans consume substantially more
salt than they need. Decreasing salt intake is advisable to reduce the
risk of elevated blood pressure. Keeping blood pressure in the normal
range reduces an individual's risk of coronary heart disease, stroke,
congestive heart failure, and kidney disease.
Many American adults will develop hypertension
(high blood pressure) during their lifetime. Lifestyle changes can
prevent or delay the onset of high blood pressure and can lower elevated
blood pressure. These changes include reducing salt intake, increasing
potassium intake, losing excess body weight, increasing physical
activity, and eating an overall healthful diet.
Key Recommendations
● Consume less than 2,300 mg (approximately 1 tsp
of salt) of sodium per day.
● Choose and prepare foods with little salt. At
the same time, consume potassium-rich foods, such as fruits and
vegetables.
Key Recommendations for Specific Population Groups
● Individuals with hypertension, blacks, and
middle-aged and older adults. Aim to consume no more than 1,500 mg of
sodium per day, and meet the potassium recommendation (4,700 mg/day)
with food.
Range of Sodium Content for Selected Foods
The ranges of sodium content for selected foods
available in the retail market. This table is provided to exemplify the
importance of reading the food label to determine the sodium content of
food, which can vary by several hundreds of milligrams in similar foods.
Source:
Agricultural Research Service Nutrient Database for Standard Reference,
Release 17 and recent manufacturers label data from retail market
surveys. Serving sizes were standardized to be comparable among brands
within a food. Pizza and bread slices vary in size and weight across
brands.
Note: None of the
examples provided were labeled low-sodium products.
Consuming More Potassium is Another Way to Lower
Blood Pressure
Another dietary measure to lower blood pressure is
to consume a diet rich in potassium. A potassium-rich diet also blunts
the effects of salt on blood pressure, may reduce the risk of developing
kidney stones, and possibly decrease bone loss with age.
The recommended intake of potassium for adolescents
and adults is 4,700 mg/day.
Potassium should come from food sources. Fruits
and vegetables, which are rich in potassium with its bicarbonate
precursors, favorably affect acid-base metabolism, which may reduce risk
of kidney stones and bone loss.
Potassium-rich fruits and vegetables include leafy
green vegetables, fruit from vines, and root vegetables. Meat, milk,
and cereal products also contain potassium, but may not have the same
effect on acid-base metabolism. Dietary sources of potassium are listed
below.
Considerations for Specific Population Groups
Individuals With Hypertension, Blacks, and
Middle-Aged and Older Adults. Some individuals tend to be more salt
sensitive than others, including people with hypertension, blacks, and
middle-aged and older adults. Because blacks commonly have a relatively
low intake of potassium and a high prevalence of elevated blood pressure
and salt sensitivity, this population subgroup may especially benefit
from an increased dietary intake of potassium. Dietary potassium can
lower blood pressure and blunt the effects of salt on blood pressure in
some individuals. While salt substitutes containing potassium chloride
may be useful for some individuals, they can be harmful to people with
certain medical conditions. These individuals should consult a
healthcare provider before using salt substitutes.
Food Sources of Potassium ranked by milligrams of
potassium per standard amount, also showing calories in the standard
amount. (The AI for adults is 4,700 mg/day potassium.)
Food,
Standard Amount
Potassium
(mg)
Calories
Sweetpotato, baked, 1 potato (146 g)
694
131
Tomato
paste, ¼ cup
664
54
Beet
greens, cooked, ½ cup
655
19
Potato,
baked, flesh, 1 potato (156 g)
610
145
White
beans, canned, ½ cup
595
153
Yogurt,
plain, non-fat, 8-oz container
579
127
Tomato
puree, ½ cup
549
48
Clams,
canned, 3 oz
534
126
Yogurt,
plain, low-fat, 8-oz container
531
143
Prune
juice, ¾ cup
530
136
Carrot
juice, ¾ cup
517
71
Blackstrap molasses, 1 Tbsp
498
47
Halibut,
cooked, 3 oz
490
119
Soybeans,
green, cooked, ½ cup
485
127
Tuna,
yellowfin, cooked, 3 oz
484
118
Lima
beans, cooked, ½ cup
484
104
Winter
squash, cooked, ½ cup
448
40
Soybeans,
mature, cooked, ½ cup
443
149
Rockfish,
Pacific, cooked, 3 oz
442
103
Cod,
Pacific, cooked, 3 oz
439
89
Bananas,
1 medium
422
105
Spinach,
cooked, ½ cup
419
21
Tomato
juice, ¾ cup
417
31
Tomato
sauce, ½ cup
405
39
Peaches,
dried, uncooked, ¼ cup
398
96
Prunes,
stewed, ½ cup
398
133
Milk,
non-fat, 1 cup
382
83
Pork
chop, center loin, cooked, 3 oz
382
197
Apricots,
dried, uncooked, ¼ cup
378
78
Rainbow
trout, farmed, cooked, 3 oz
375
144
Pork
loin, center rib (roasts), lean, roasted, 3 oz
371
190
Buttermilk, cultured, low-fat, 1 cup
370
98
Cantaloupe, ¼ medium
368
47
1%-2%
milk, 1 cup
366
102-122
Honeydew
melon, 1/8 medium
365
58
Lentils,
cooked, ½ cup
365
115
Plantains, cooked, ½ cup slices
358
90
Kidney
beans, cooked, ½ cup
358
112
Orange
juice, ¾ cup
355
85
Split
peas, cooked, ½ cup
355
116
Yogurt,
plain, whole milk, 8 oz container
352
138
Source: Nutrient values from
Agricultural Research Service (ARS) Nutrient Database for Standard
Reference, Release 17. Foods are from ARS single nutrient reports,
sorted in descending order by nutrient content in terms of common
household measures. Food items and weights in the single nutrient
reports are adapted from those in 2002 revision of USDA Home and Garden
Bulletin No. 72, Nutritive Value of Foods. Mixed dishes and multiple
preparations of the same food item have been omitted from this table.
Background Information
Based in the western suburbs of Chicago, Loyola
University Health System is a quaternary care system with a 61-acre main
medical center campus, the 36-acre Gottlieb Memorial Hospital campus and
25 primary and specialty care facilities in Cook, Will and DuPage
counties. The medical center campus is conveniently located in Maywood,
13 miles west of the Chicago Loop and 8 miles east of Oak Brook, Ill.
The heart of the medical center campus, Loyola University Hospital, is a
570-licensed bed facility. It houses a Level 1 Trauma Center, a Burn
Center and the Ronald McDonald® Children?s Hospital of Loyola University
Medical Center. Also on campus are the Cardinal Bernardin Cancer Center,
Loyola Outpatient Center, Center for Heart & Vascular Medicine and
Loyola Oral Health Center as well as the LUC Stritch School of Medicine,
the LUC Marcella Niehoff School of Nursing and the Loyola Center for
Fitness. Loyola's Gottlieb campus in Melrose Park includes the 250-bed
community hospital, the Gottlieb Center for Fitness and the Marjorie G.
Weinberg Cancer Care Center.
The National
Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports
research related to the causes, prevention, diagnosis, and treatment of
heart, blood vessel, lung, and blood diseases; and sleep disorders. The
Institute also administers national health education campaigns on women
and heart disease, healthy weight for children, and other topics. NHLBI
press releases and other materials are available online at: www.nhlbi.nih.gov.
The National
Institutes of Health (NIH) — The Nation's Medical Research Agency —
includes 27 Institutes and Centers and is a component of the U. S.
Department of Health and Human Services. It is the primary federal
agency for conducting and supporting basic, clinical, and translational
medical research, and it investigates the causes, treatments, and cures
for both common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov
Resources:
NHLBI Diseases and Conditions Index: High Blood
Pressure
Jan. 29, 2009 – Many senior citizens struggle in a
battle against high blood pressure and a key goal is to avoid as much
salt as possible, which is challenging because of its wide use in many
foods. There is new hope, however, in research that finds adding more
potassium to the diet can offset the harmful effects of sodium to reduce
the risk of cardiovascular disease.
Nearly all Americans consume substantially more
salt than they need. Decreasing salt intake is advisable to reduce the
risk of elevated blood pressure. Keeping blood pressure in the normal
range reduces an individual's risk of coronary heart disease, stroke,
congestive heart failure, and kidney disease. 
Another dietary measure to lower blood pressure is
to consume a diet rich in potassium. A potassium-rich diet also blunts
the effects of salt on blood pressure, may reduce the risk of developing
kidney stones, and possibly decrease bone loss with age.