I have not found any research indicating increased risk for hemorrhagic stroke in low fat plant based diets when hypertension is not present. I think the increased incidence of this type of stroke in the Japanese is related to the fish they eat. This is from the University of Maryland Medical Center website:
"Strong evidence from population-based studies suggests that omega-3 fatty acid intake (primarily from fish) helps protect against stroke caused by plaque buildup and blood clots in the arteries that lead to the brain. In fact, eating at least 2 servings of fish per week can reduce the risk of stroke by as much as 50%. However, people who eat more than 3 grams of omega-3 fatty acids per day (equivalent to 3 servings of fish per day) may be at an increased risk for hemorrhagic stroke, a potentially fatal type of stroke in which an artery in the brain leaks or ruptures. Omega-3 fatty acids may increase the chances of bleeding, especially in those taking anticoagulant medications, such as warfarin (Coumadin) or even aspirin.:Read more:
http://www.umm.edu/altmed/articles/stro ... z1u6lPObMp