Onions have been shown to contain adenosine and other 'blood thinners' that help to prevent the formation of blood clots. To thin the blood, onions reportedly help keep the coronary arteries open and clear by increasing the HDL.
In a study of 87,000 nurses conducted by Brigham and Women's Hospital and Harvard University, compared with those who ate one serving a month or less, subjects who ate five or more servings of carrots every week had a 68-percent lower risk of suffering stroke. Carrots are rich in beta-carotene and other carotenoids, all members of the vitamin A family. Eating a lot of fruits and veggies that are rich in beta-carotene and vitamin C and E, can reduce the risk of having the stroke by as much as 54 percent if they enjoy carrots often.
https://worldhealthreviews.com/cardio-clear-7-review-pdf/