PJ's Fitness Blog

A blog about a fitter you. Come find out what is on the cutting edge of fitness science and be a part of the ongoing conversation.

High-Carb Foods Harm Your Heart

Click for full story and printer friendly version

When researchers talk about “carbohydrates”, they really mean sugars and refined flour products like white bread. These empty-calorie foods dominate most Americans’ diets … and when consumed in excess, they cause fat gain, raise blood sugar levels, promote inflammation, and raise heart and diabetes risks.

There is already plenty of evidence that diets high in carbohydrate-laden foods like pastries, white bread, and refined-flour cereals can be detrimental to cardiac health, but in a new landmark study, research from Tel Aviv University now shows exactly how these high-carb foods raise the risk of cardiovascular disease (Shechter M et al. 2009).

The Israeli researchers divided 56 healthy volunteers into four groups and assigned them to eat one of four things:
· Cornflake mush mixed with milk
· Pure sugar mixture
· Bran flakes
· Placebo (water)

Corn flakes and sugar are very-high-carb foods with high “glycemic index” numbers, which cause sharp spikes in blood sugar levels. Bran flakes are a bit better, but still fairly high in carbs.

Dr. Shechter applied his method of “brachial reactive testing” to each group. The test uses a cuff on the arm, like those used to measure blood pressure, which can visualize arterial function in real time. Using a technique pioneered by his laboratory, Dr. Shechter was able to see what happens inside our arteries before, during and after eating high carb foods.

In a first for medical history, his team used novel technology to peer inside the arteries of students after they ate. The results were dramatic. During consumption of foods high in sugar, there was a temporary and sudden dysfunction in the endothelial walls of the arteries.
Before any of the patients ate, arterial function was essentially the same. After eating, except for the placebo group, all showed impaired arterial function.

Enormous peaks indicating arterial stress were found in the high glycemic index groups: that is, the students who ate cornflakes and sugar. He saw that these high-carb foods distended the students’ brachial arteries for several hours. Elasticity of arteries can be a measure of heart health. But repeated, sudden expansion of the artery wall can cause a number of negative health effects, including reduced elasticity, which can cause heart disease or sudden death.

Endothelial health can be traced back to almost every disorder and disease in the body. It is “the riskiest of the risk factors,” said Dr. Shechter. “We knew high glycemic foods were bad for the heart. Now we have a mechanism that shows how. “Foods like cornflakes, white bread, french fries, and sweetened soda all put undue stress on our arteries. We’ve explained for the first time how high glycemic carbs can affect the progression of heart disease.”

“It’s very hard to predict heart disease,” added Dr. Shechter. “But doctors know that high glycemic foods rapidly increase blood sugar. Those who binge on these foods have a greater chance of sudden death from heart attack. Our research connects the dots, showing the link between diet and what’s happening in real time in the arteries.”
We also know now that low fat eating isn’t nearly as effective for fat loss as low carb eating. Since high carb eating causes us to gain fat so easily, it’s no wonder we are now the fattest nation on the planet! Sure the research backs these positions up, but if you are still in doubt, do your own case studies: Just follow obese people at the supermarket and see what they put in their cart. Case closed.
Also, have you even wondered why you don’t see any really old obese people, and why ALL of the “centurians” (people over 100 years old) are of healthy weight? Things that make you go hmmmmm…
References:

  • Lavi T et al. The acute effect of various glycemic index dietary carbohydrates on endothelial function in nondiabetic overweight and obese subjects. J Am Coll Cardiol. 2009 Jun 16;53(24):2283-7.

  • Shechter M et al. Long-term association of brachial artery flow-mediated vasodilation and cardiovascular events in middle-aged subjects with no apparent heart disease. Int J Cardiol. 2009 May 1;134(1):52-8. Epub 2008 May 13.

Adapted from Craig Weatherby’s article: http://newsletter.vitalchoice.com/e_article001485331.cfm?x=bfMJGBg,b1h35Dn4