Devouring a big plate of leafy spinach may do more than just please your mother.
A new study once again confirms that leafy green vegetables are good for you.
In the three-part study, researchers looked at the effect lutein, a yellow pigment found in leafy green vegetables and egg yolks, had in humans, artery cell samples and mice.
More Lutein Means Less Thickening of Arteries
In one part, researchers studied 480 men and women who had no history of heart disease and looked at the thickness of their arteries and the levels of lutein in their blood. People with more lutein had less thickening of their arteries than those with low levels of lutein.
In the cell study, researchers placed lutein in the cells and found the same results. When they injected lutein in the mice, there arteries also had less thickening.
Researchers found the more lutein found, the less thickening of the wall of the arteries in mice, men and tissue samples.
"It's still important to go from here to intervention studies in which we control the diets to persons and see what the effects of dark green leafy vegetables on the progression of atherosclerosis," said lead author James Dwyer, professor of preventive medicine at the University of Souther California.
Thickening of the walls of arteries in the neck may be related to low levels of lutein, the researchers say. Neck or carotid artery thickness is a good indication of atherosclerosis throughout the body. Atherosclerosis is the disease that leads to most heart attacks and strokes.
Eat Your Veggies, Not Supplements
The findings help explain why fruit- and vegetable-rich diets seem to protect cardiovascular health. The study results are published in today's issue of the journal Circulation.
Atherosclerosis accounts for more than 1.5 million heart attacks and 600,000 strokes every year in the United States.
"Since we already know, and there is quite a bit of evidence, that the increased intake of vegetables is protective against a number of diseases, we should use these results to increase the intake of the leafy green vegetables into our diets with confidence," Dwyer said.
But don't go out and buy lutein supplements to clean out your carotids just yet. Lutein, like beta-carotene, is in a class of nutrients called carotenoids. Recent studies have shown that beta-carotene supplements cannot reduce heart disease. In fact, in some cases, the supplements were associated with increased risk of angina and other heart complications.
"We know from the beta-carotene studies that we cannot rely on supplements," Dwyer said. "We should not use these results as a reason to use supplements."