High Fat, Sodium Intake Are Risk
Factors for Stroke
February 4, 2005
By Martha Kerr
The results of a large urban multiethnic study show
that high fat and high sodium diets are both risk factors
for stroke, investigators with the Northern Manhattan
Study (NOMAS) reported here Thursday.
NOMAS is an ongoing epidemiological study being conducted
at Columbia University Medical School in New York. Investigators
administered dietary questionnaires to 3,183 area residents.
The average age of the subjects was 70 years; 21 percent
were white, 24 percent black and 52 percent Hispanic.
During 5.5 years of follow-up, 142 strokes have occurred.
The participants were divided into four subgroups according
to the level of fat in their diet. These amounts were
compared dietary fat levels recommended by the American
Heart Association, which are 65 grams of fat per day
-- based on a 2,000 calorie diet with 30 percent of
calories derived from fat.
The subjects who ate the most fat each day had a 64
percent greater chance of having a stroke compared with
those who ate the lowest levels, postgraduate research
fellow Halina White reported at the American Stroke
Association's International Stroke Conference 2005.
This figure was obtained after other factors that affect
stroke risk were considered including age, gender, education
level, race, ethnicity, high blood pressure, heart disease,
diabetes, moderate alcohol consumption, smoking, body
mass index and physical activity. She said subjects
in the lowest dietary fat group consumed about 24 grams
per day, while those in the highest group consumed more
than 115 grams per day.
"Fat, particularly saturated fat...has an almost
hormonal effect on the blood, causing the release of
cholesterol, among other effects," White told Reuters
Health. "Polyunsaturated fats have the opposite
effect."
Neurology resident Armistead D. Williams, III, also
presented data from NOMAS showing that a high sodium
intake increases stroke risk. The same group of subjects
was divided into four subgroups according to daily sodium
consumption -- more than 4 grams, 3 to 4 grams, 2.4
to 3 grams, and less than 2.4 grams.
About one fifth of the study group consumed more than
4 grams of sodium a day, Williams noted.
The investigators used 2.4 grams as a reference level
because an intake of 2.4 grams sodium daily or less
meets the American Heart Association recommendation.
Consumption of more than 4 grams sodium a day increased
stroke risk by 90 percent compared with the reference
group, Williams reported. This was consistent regardless
of whether or not the subject had high blood pressure,
he added.
NOMAS lead investigator Dr. Ralph L. Sacco noted that
"we can't exclude the blood pressure effect, but
it is small."
Williams told Reuters Health that it is possible that
the sodium is increasing the rigidity of the artery
walls. "That's one of the things we're going to
look at when we get back to New York."
Source:www.reuters.com
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