High glycemic foods make the major blood vessel of our upper arms swell out or expand from internal pressure, according to new research. This brachial artery is the most convenient place that scientists and doctors have to measure how elastic our arteries are.
The elasticity of our arteries anywhere in our body is a measure of our heart health. When the walls of an artery anywhere in our body expand suddenly, this can lead to heart disease or sudden death.
Those of us who have diabetes need to do what we can to keep our arteries healthy. The statistics are shocking: 68 percent of Americans 65 or older die from heart disease, and adults with diabetes are two to four times more likely to die from a heart attack than other Americans.
The Journal of the American College of Cardiology just published the important study, "The Acute Effect of Various Glycemic Index Dietary Carbohydrates on Endothelial Function in Nondiabetic Overweight and Obese Subjects." Only the abstract is free online. But the principal author, Dr. Michael Shechter, kindly send me a PDF of the article's full text. He is the senior cardiologist and director of the Clinical Research Unit at Tel Aviv University's Sackler Faculty of Medicine.
Note that Dr. Shechter and his associates studied people who do not have diabetes. Clearly, if they studied people like us, their results would be different -- almost certainly even more dramatic, because we react even more strongly to high glycemic foods.
Those of us who have diabetes have known for years that high glycemic foods can spike our blood glucose levels. But this study adds a whole new dimension of concern about a high glycemic diet.
This study found no correlation between endothelial dysfunction and high blood glucose levels. Clearly, something more is going on, but the researchers aren't sure what it is. They speculate that the culprit could be changes in free fatty acids and inflammatory cytokines, insulin, adiponectin, ghrelin, nitric oxide, endothelial nitric oxide synthase expression, intracellular adhesion molecules, or endothelin.
Count on the answer to that question as a forthcoming research finding. Meanwhile, whatever the cause, we know now that eating foods high on the glycemic index will not only spike our blood glucose levels but will also directly damage our hearts.
Endothelial dysfunction is a root cause of heart attacks and strokes. It is "the riskiest of the risk factors," Dr. Shechter says.
Recently, when I was in Houston to attend the annual convention of the American Association of Clinical Endocrinologists, I took the opportunity to get tested on the VENDYS device made by Endothelix Inc., which measures vascular endothelial dysfunction. My arteries are fine, thanks in large part to following a low glycemic diet for the past 14 years. My diet is now very low-carbohydrate, but that means it's low glycemic in spades.
Most Americans, on the other hand, start their day with a breakfast cereal, and many of us choose Corn Flakes. I don't have the U.S. statistics. But about half of the people in the U.K. eat cereal for breakfast, and "Kellogg's Corn Flakes is the U.K.'s and Europe's number one breakfast cereal."
Corn Flakes cereal has a high glycemic index, approximately 80 on the scale where glucose is 100. Dr. Shechter and his associates divided the 56 volunteers into four groups, comparing their responses on Corn Flakes, glucose, a high-fiber cereal (GI of about 40), and water.
Unless you prefer pure glucose, Corn Flakes cereal is perhaps the fasting way to spike your blood glucose levels. We knew that, but now we also know that high glycemic foods, like Corn Flakes cereal, are some of the best ways to damage our hearts.