THURSDAY, April 19 (HealthDay News) -- In what the researchers
say is the largest study on the issue to date, adults who consumed
higher amounts of low-fat dairy products also had a somewhat lower
long-term risk of stroke.
The study involved nearly 75,000 Swedish adults who were tracked
for an average of 10 years after completing a dietary
questionnaire.
Those who consumed low-fat versions of products such as milk,
yogurt or cheese had a 12 percent lower risk for stroke than those
whose diet typically included high/full-fat versions of these dairy
staples.
"I think this finding certainly makes sense," said Lona Sandon, a dietician and assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas. "When you have more high-fat dairy you have more saturated fat, which we know is one of the types of fats that can affect LDL, or 'bad,' cholesterol levels. And eating saturated fat leads to clogging up arteries in the heart and the brain. So then you're more likely to have the clots breaking off and causing something like an ischemic stroke."
However, "when you're looking at stroke risk you'd really want
to look at an individual's whole dietary pattern," said Sandon, who
was not involved in the new research. "But it is certainly
plausible that whole-fat dairy bumps up the risk that is out
there."
A research team led by Susanna Larsson, from the division of
nutritional epidemiology at the National Institute of Environmental
Medicine at Stockholm's Karolinska Institute, reported the findings
April 19 in the journal
Stroke.
The study authors noted that in the United States, about
one-third of all adult men and women over the age of 18 have high
blood pressure, which they describe as a "major controllable risk
factor" for stroke. Still, they added, only about half of affected
Americans have their blood pressure under control.
With that in mind, experts have long touted the benefits of the
Dietary Approaches to Stop Hypertension (DASH diet), with its
emphasis on low-fat dairy consumption.
In 1997, the Swedish team administered food surveys to almost
75,000 men and women between the ages of 45 and 83, none of whom
had a prior history of either heart disease or cancer.
From that point forward, the incidence of stroke among study
participants was monitored via data collected by the Swedish
Hospital Discharge Registry.
Over the course of about a decade, nearly 4,100 strokes
occurred, the authors noted. People who stuck to low-fat dairy
products appeared to have a somewhat lower risk for stroke. The
study was only able to find an association between eating low-fat
dairy products and lowered odds for stroke; it could not prove
cause-and-effect.
The Swedish researchers called for further large studies to
examine the apparent association, while at the same time suggesting
that, if it holds up upon further scrutiny, the finding could have
broad public health implications.
Larsson's team pointed out that when it comes to dairy
consumption, the typical North American diet closely mirrors that
of northern Europeans, so a snapshot of Swedish diets and stroke
risk might be relevant to a U.S. population.
"The bottom line is that if you're consuming more fat in your day -- no matter where it's coming from -- it is going to increase your risk for atherosclerosis [hardening of the arteries], and thereby your risk for stroke," said Sandon. "And that's what's behind the USDA's Dietary Guidelines for Americans, which recommends that you get three dairy servings per day, in order to get enough calcium and potassium, but at the same time making sure that those servings are low-fat."
Larsson's study was funded by the Swedish Council for Working
Life and Social Research and the Swedish Research Council.
More information
For more on how diet impacts stroke risk, head to the
National Stroke Association.