Cornflakes, White Bread Could Boost Heart Risk

June 12 -- THURSDAY, June 11 (HealthDay News) -- Eating a diet rich in carbohydrates that boost blood sugar levels -- foods such as cornflakes or white bread -- may hamper the functioning of your blood vessels and raise your risk of developing cardiovascular disease, a new study suggests.

And another study, released Thursday at the Endocrine Society's annual meeting in Washington, D.C., found that people might actually feel fuller -- and might therefore eat less -- if they cut back a bit on carbohydrates in their diet.

In the first study, researchers from Israel's Chaim Sheba Medical Center and elsewhere evaluated 56 healthy but overweight or obese men and women, aged 35 to 60. None had diabetes or a history of hospitalizations for cardiovascular disease.

The researchers fed the men and women on four different mornings, following overnight fasts. They were served either glucose, cornflakes, high-fiber cereal or water, in descending order of glycemic index.

Low-glycemic index foods include oatmeal, most fruits and vegetables, legumes and nuts. White bread, cornflakes and instant potatoes are high-glycemic indexes. The higher the glycemic index, the more that food raises blood sugar levels.

Before and after the meals or the water, the team of researchers measured the functioning of the endothelium, the layer of cells that line the inside of blood vessels. If the endothelial function is poor, it is thought to increase the risk of cardiovascular disease.

The measurement used is called brachial artery flow-mediated dilation (FMD), which measures how well the endothelium is functioning. Researchers also measured the participants' blood sugar levels.

The blood sugar levels before and two hours after the meals were similar, but they were higher at 30 to 90 minutes after the high-glycemic meals.

The FMD was reduced two hours after eating for all groups, but the reduction was more marked after the high-glycemic meals.

The high-glycemic meals, the authors conclude, appeared to impair the endothelial function.