Stampfer and his colleagues analyzed data from the long-term Nurses' Health Study that began in 1980. All of the participants were free of known heart disease and cancer. From the questionnaires, researchers calculated each woman's fat and protein consumption. Hemorrhagic strokes occur when a small or medium blood vessel inside the brain leaks or bursts. Most strokes are ischemic strokes, which result from the blockage of an artery carrying blood to the brain.
Intraparenchymal hemorrhage is one of the less common forms of a hemorrhagic stroke.
The researchers divided the women into five groups, or quintiles, ranked from the lowest to highest for consumption of each of several types of fat, protein, as well as stroke risk factors. The increased stroke risk observed in the group that consumed the least amount of saturated fat occurred primarily among women with high blood pressure. Our thinking is that individuals with a very low intake of saturated fat may develop some kind of structural impairment of the arteries, and this makes them more vulnerable to stroke if they have high blood pressure. The amount of dietary cholesterol, polyunsaturated fat, and total fat consumed did not significantly increase the risk of this type of stroke. They did report, however, a modest trend toward a lower risk of intraparenchymal hemorrhagic stroke with increased monounsaturated fat consumption.