Low-Fat Dairy Linked to Lower Stroke Risk

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.

SOURCES: Lona Sandon, R.D., dietician and assistant professor of clinical nutrition, University of Texas Southwestern Medical Center at Dallas; April 19, 2012, Stroke