It's a serious condition that's often one of the first signs of heart disease.
Of the 200 51- to 86-year-old people in the study presented at the American Heart Association's Arteriosclerosis, Thrombosis and Vascular Biology 2013 Scientific Sessions, 40 percent were women.
All had risk factors for blood vessel disease and nearly three-quarters had endothelial dysfunction.
The diet restricted foods high in the sugar-binding protein lectin, generally regarded as a healthy nutrient.
The restricted foods included grains, beans, fruit, poultry and plants belonging to the nightshade family, which includes tomatoes.
At the same time, patients consumed plenty of leafy greens, shellfish and fish, olive oil and grass-fed animal protein, while taking supplements containing the antioxidant polyphenol from fish oil, grape seed extract and vitamins. Antioxidants are thought to slow cell ageing.
"These findings represent a fundamental paradigm shift in how the diseases of the 'Western Diet' should be treated," Steven R. Gundry, M.D., lead author and medical director of the International Heart and Lung Institute at The Center for Restorative Medicine in Palm Springs, California said.
"Simple removal of 'healthy' lectin-containing foods, and taking a few inexpensive supplements, may restore endothelial function to normal, which in turn can reverse high blood pressure, diabetes and obesity," he said.
Despite the study's findings, consumers shouldn't eliminate tomatoes or other healthy foods from their diets, said the American Heart Association, which recommends consuming a diet with plenty of fruits, vegetables, whole grains and fish.