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 Potassium-rich diets have been linked to lower blood pressure
before, but this is the first time potassium has been tied to stroke
risk, said senior author Sylvia Wassertheil-Smoller of the
Department of Epidemiology and Population Health at Albert Einstein
College of Medicine in New York.
Her team analyzed data from the Women’s Health Initiative study on
90,137 postmenopausal women, ages 50 to 79. At one and three years
after enrollment, the women filled out dietary questionnaires.
Overall, they stayed in the study for an average of 11 years.
The researchers used the dietary questionnaires and potassium values
for common foods to determine that the women consumed an average of
2,611 milligrams of potassium per day.
According to Food and Drug Administration labels, adolescents and
adults should be consuming at least 4,700 mg of potassium daily.
Bananas, avocados and other fruits and vegetables are good sources
of potassium. A medium-sized banana has about 420 mg of potassium,
while a cup of avocado has 708 mg.
The researchers then divided the women into four groups based on
potassium consumption, from those who got less than 1,926 mg per
day, the least potassium, to those who got more than 3,194 mg per
day, the most.
Each year, out of every 1,000 women in the study, about three
suffered a stroke and nearly 12 died of any cause.
Women who ate the most potassium were 12 percent less likely to
suffer a stroke and 10 percent less likely to die during the study
period than those who ate the least, according to results in Stroke.
“Potassium is a vital component of cellular function,”
Wassertheil-Smoller said. “It affects endothelial cells which line
blood vessels, so perhaps it may provide more blood flow to critical
areas – that is one thought, but we don't really know.”
The effect was strongest for women without high blood pressure,
which was surprising, Wassertheil-Smoller told Reuters Health by
email.
“This and previous observational studies cannot prove that it is
potassium that lowers stroke risk,” said Susanna C. Larsson of the
Institute of Environmental Medicine at Karolinska Institutet in
Stockholm, Sweden.
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Larsson was not involved in the new research.
“It may be other nutrients or combinations of nutrients in
potassium-rich foods that are protective,” she told Reuters Health
by email.
Maintaining a healthy body weight, being physically active, not
smoking, and drinking alcohol in moderation reduces the risk for
stroke, Larsson said.
“The reduction in stroke risk associated with a high dietary
potassium intake is quite modest compared with other modifiable risk
factors such as smoking,” she said.
Potassium in food may be more beneficial than potassium in
supplements, Wassertheil-Smoller said.
The relationship between potassium and stroke is likely the same for
men, although men tend to eat both more calories and more potassium
in a day, she said.
The U.S. Department of Agriculture and the Institute of Medicine
recommend 4,700 mg of potassium per day regardless of age or sex,
while the World Health Organization recommends about 3500 mg per
day, but most people in the U.S. don’t meet either of those goals,
she said.
SOURCE: http://bit.ly/1ol13Ej
Stroke, September 4, 2014
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