Salt
Too much salt can raise anyone's stroke risk, researchers say. Even for people who don't have hypertension, just half a teaspoon less per day can significantly improve cardiovascular health.
If everyone in the United States lowered daily salt intake by three grams, it would save an estimated $24 Billion in healthcare costs each year, and prevent nearly 100,000 heart attacks and as many as 66,000 strokes.
That means, primarily, avoiding processed foods and microwave meals, though some companies are working on reducing sodium levels. Another way to reduce salt is to season food more aggressively, so you don't miss it.