Science has apparently proven what your mom knew all along: eating your veggies is really good for you. But like your mom, even scientists still don't know why.

A new study proves how good: cruciferous vegetables -- that is cabbage, Brussels sprouts, broccoli, and cauliflower -- can lower your risk of stroke and heart disease, according to new research from the University of Western Australia.

The team recorded the diets of over 900 women above the age of 70, then measured the thickness of the walls of their carotid arteries -- the main artery in your neck. A thickened carotid artery has previously been linked to heart disease and stroke risk.

Women who reported eating three or more portions of vegetables a day had thinner artery walls, compared to women who ate fewer than two portions of vegetables a day. Thinner artery walls mean blood vessels are clearer, making them more able to move blood around.

But not all veggies appear to be equally effective. Cruciferous vegetables seemed to have the biggest association with artery wall thinness.

ABC reports the research is far from conclusive. The study only shows an association between vegetable intake and artery wall thickness, not a cause-and-effect relationship.