Getting plenty of low-fat milk, yogurt, and other dairy in the diet is associated with lower stroke risk, Swedish researchers found.
The more low-fat dairy consumed, the lower the ischemic stroke risk (P=0.03 for trend), Susanna C. Larsson, PhD, of the Karolinska Institute in Stockholm, and colleagues reported in the July issue of Stroke: Journal of the American Heart Association.
In the dairy-loving Swedish population they examined, the highest consumers of low-fat dairy - with a median four servings a day, along with more than five full-fat portions - were 12% less likely to have a stroke after adjustment for a full range of other factors than were those with no consumption.
Full-fat milk, cream, and cheese didn’t help, but didn’t hurt either in the analysis of the prospective, population-based cohorts.
While the observational study couldn’t draw any conclusions about causality, low-fat dairy might have a real impact via reducing blood pressure, the researchers suggested.
Clinical and preclinical studies have shown that the proteins in milk products can lower blood pressure compared with placebo. Vitamin D fortification of dairy may also fight hypertension, which is a strong predictor of stroke.
In 1997, the study participants, who ranged in age from 45 to 83, answered a lengthy questionnaire that covered many aspects of their lifestyle and personal characteristics, including diet, exercise habits, body mass index, work, education, and medical history. At the time they enrolled in the study, none of them had had any history of heart disease, stroke, or cancer. That would change over the next 10 years.
During the decade-long follow up, slightly more than 4,000 of the participants - about 2,400 of them men - had a stroke. More than three quarters of the strokes were ischemic, in which an artery that supplies blood to the brain becomes blocked, frequently by a clot. Nearly 600 of the strokes were hemorrhagic, which occur when a blood vessel in the brain bursts.
The researchers found that consuming full-fat dairy products such as whole milk was not associated with risk of stroke. They suggest that full-fat dairy foods may increase LDL (“bad” cholesterol) levels and counteract some of the beneficial effects of eating dairy foods.
“A diet rich in low-fat dairy foods has been recommended to prevent and reduce hypertension on the basis of strong evidence,” Larsson’s group wrote, noting it as a component of the Dietary Approaches to Stop Hypertension (DASH) diet.
Healthy Diet Is Major Part of Stroke Prevention
“This is a good study that adds to what we already know about low-fat diets,” says neurologist Wayne Clark, MD, director of the Oregon Stroke Center at Oregon Health and Science University in Portland.
Clark says the calcium in dairy products may also help lower blood pressure, and he recommends two to three servings per day. However, he points out that diet is only one part of stroke prevention.
“Eating a healthy diet, quitting smoking, and increasing your exercise can reduce your stroke risk by 50%,” says Clark. “Those are the big three, and by focusing on all of them, you can take control of your health.”
The group analyzed the Swedish Mammography Cohort and Cohort of Swedish Men, which both included detailed dietary questionnaire data and long-term follow-up through national healthcare records.