Male smokers who consume more
magnesium appear to have a lower risk for cerebral infarction, a type
of stroke that occurs when blood flow to the brain is blocked,
according to a report in the March 10 issue of Archives of Internal
Medicine, one of the JAMA/Archives journals.
Recent studies
indicate that changes in diet may help prevent stroke, according to
background information in the article. Hypertension, or high blood
pressure, is a risk factor for stroke; therefore, dietary measures that
reduce blood pressure may in turn affect stroke risk. Consuming more
magnesium, calcium and potassium has been associated with lower blood
pressure in previous studies, while sodium has been positively
associated with hypertension.
Susanna C. Larsson, Ph.D., of
the Karolinska Institutet, Stockholm, Sweden, and colleagues analyzed
the diets of 26,556 Finnish male smokers age 50 to 69 years who had not
previously had strokes. In addition to the types of food they ate, the
men reported other characteristics including medical, smoking and
physical activity histories. Their height, weight and blood pressure
were recorded, and a blood sample was taken.
During an average
of 13.6 years of follow-up, 2,702 of the men had cerebral infarctions;
383 had intracerebral hemorrhages, which involve bleeding into the
brain tissue; 196 had subarachnoid hemorrhages, or bleeding between the
brain and the thin tissues that cover it; and 84 had unspecified types
of strokes.
After adjusting for age and cardiovascular risk
factors, such as diabetes and cholesterol level, men who consumed the
most magnesium (an average of 589 milligrams per day) had a 15 percent
lower risk for cerebral infarction than those who consumed the least
(an average of 373 milligrams per day). The association was stronger in
men younger than 60 years. Magnesium intake was not associated with a
lower risk of intracerebral or subarachnoid hemorrhage, and calcium,
potassium and sodium intake were not associated with risk for any type
of stroke.
“An inverse association between magnesium intake
and cerebral infarction is biologically plausible,” the authors write.
In addition to lowering blood pressure, magnesium may influence
cholesterol concentrations or the body’s use of insulin to turn glucose
into energy. Either of these mechanisms would affect the risk for
cerebral infarction but not hemorrhage.
The results “suggest
that a high consumption of magnesium-rich foods, such as whole-grain
cereals, may play a role in the prevention of cerebral infarction,”
they write. “Whether magnesium supplementation lowers the risk of
cerebral infarction needs to be assessed in large, long-term randomized
trials.”
###
(Arch Intern Med. 2008;168[5]:459-465. Available pre-embargo to the media at www.jamamedia.org.)
Editor’s
Note: The ATBC Study was supported by Public Health Service contracts
from the National Cancer Institute. Dr. Larsson’s postdoctoral research
at the National Public Health Institute was supported by a grant from
the Swedish Council for Working Life and Social Research. Please see
the article for additional information, including other authors, author
contributions and affiliations, financial disclosures, funding and
support, etc.
Contact: Susanna C. Larsson
Susanna.Larsson@ki.se
JAMA and Archives Journals
