A healthy dose of vegetables every day may help keep the heart arteries clear, a study in mice suggests. Researchers found that lab mice given a diet full of broccoli, carrots, green beans, corn and peas developed far less artery narrowing than those reared on a veggie-free diet.
For humans, the findings offer more support for the advice health experts and mothers have long given: eat your vegetables.
Discounting French fries, most Americans aren't adequately heeding that advice, noted the study's lead author, Dr. Michael R. Adams of Wake Forest University School of Medicine in Winston-Salem, North Carolina.
The new research, he explained in an interview, adds to what's known about the health benefits of vegetables by showing that they may thwart the progression of atherosclerosis, a hardening and narrowing of arteries that can lead to heart disease and stroke.
Some studies have found that people who eat more vegetables tend to have fewer heart attacks, but studies such as those are not definitive. The current study, published in the Journal of Nutrition, appears to be the first to look at whether vegetable consumption can interfere with the process of atherosclerosis.
Adams and his colleagues studied mice that were genetically altered and bred to quickly develop the artery-clogging plaques that mark atherosclerosis. Starting at 6 weeks of age, half of the mice went on the veggie-rich diet — with 30 percent of calories coming from freeze-dried vegetables — while the other half followed a vegetable-free regimen.
Sixteen weeks later, the researchers found, the extent of atherosclerosis was 38 percent less in the vegetable-fed mice.
The animals also had somewhat lower cholesterol and much lower levels of a protein involved in inflammation — which may help explain the clearer arteries, according to Adams.
Chronic inflammation in the blood vessels is believed to contribute to atherosclerosis, and research shows that plant compounds called polyphenols have both anti-inflammatory and antioxidant powers. Vegetables are also rich in vitamins that act as antioxidants, which means they neutralize cell-damaging molecules called oxygen free radicals.
The study focused on broccoli, green beans, peas, corn and carrots in part because they are among the most commonly consumed vegetables in the U.S. It's entirely possible, Adams said, that other vegetables have similar benefits against atherosclerosis, but they have yet to be studied.
General Mills Co., maker of the Green Giant brand of canned and frozen vegetables, funded the study.