There's a helpful editorial in last month's American Journal of Clinical Nutrition (AJCN) - "Fruit and vegetables: think variety, go ahead, eat!" As with many journals, one doesn't have to pay anything to look at the full text of AJCN editorials. It's a good read. It comments on a paper in the journal by Myint et al showing a 42% reduction in stroke for those in the highest quartile - the top 25% - of plasma vitamin C compared with those in the lowest quartile (independently of other risk factors such as smoking, exercise, age, weight and so on).