Hoe snelle koolhydraten hartproblemen veroorzaken*
Het is al lang bekend dat voeding met een hoge glycemische index (GI) slecht zijn voor hart en bloedvaten, Israëlische wetenschappers hebben nu onderzocht waarom dat is. Door een speciale techniek kon als het ware in de slagaders gekeken worden. 56 gezonde studenten werden gezocht om 4 weken lang testen te ondergaan bij het eten van verschillende voeding, al dan niet met hoge GI of water als placebo. Bij aanvang van de studie had iedereen vergelijkbare metingen en een vergelijkbaar functioneren van de slagaders. Bij en tot wel enkele uren na het eten van voeding met hoge GI veranderde die bevindingen fors als plotseling optredend gevolg van zij het tijdelijk disfunctioneren van de laag endotheelcellen aan de binnenkant van de bloedvaten. Dit disfunctioneren kan leiden tot hartproblemen, een hartaanval of zelfs een hartstilstand.
How ‘high carb’ foods cause heart attacks
It has been commonly known for a number of years that certain foods, such as white bread and corn flakes, are bad for cardiac health, but new research from Israeli scientists shows just how 'high carb' foods cause heart attacks.
The researchers at Tel Aviv University have carried out a study which shows exactly how high carb foods increase the risk for heart problems - Dr Michael Shechter of Tel Aviv University's Sackler School of Medicine and the Heart Institute of Sheba Medical Center working in collaboration with the Endocrinology Institute "looked inside" the arteries of students as they were eating a variety of foods.
By using a clinical and research technique pioneered by his laboratory in Israel, Dr Shechter was able to visualize what happens inside arteries before, during and after eating high carb foods and exactly what happens inside the body when the wrong foods for a healthy heart are eaten and he found that foods with a high glycemic index distended brachial arteries for several hours.
The elasticity of arteries anywhere in the body can be a measure of heart health but when aggravated over time, a 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.
The landmark research represents a first in medical history and Dr Shechter says it is very hard to predict heart disease but doctors know that high glycemic foods rapidly increase blood sugar and those who over-indulge on these foods have a greater chance of sudden death from heart attack.
Dr Shechter says their research shows the link between diet and what's happening in real time in the arteries and could lead to a whole new way to show patients the effects of a poor diet on the body.
The research involved 56 healthy volunteers, divided into 4 groups :- one group ate a cornflake mush mixed with milk, a second a pure sugar mixture, the third bran flakes, while the last group was given a placebo (water).
Over a four week period, Dr. Shechter applied his method of "brachial reactive testing" to each group - this uses a cuff on the arm similar to those used to measure blood pressure, which can visualize arterial function in real time.
The results were apparently quite dramatic - before any of the patients ate, arterial function was essentially the same - but after eating, except for the placebo group, all had reduced functioning and enormous peaks indicating arterial stress were found in the high glycemic index groups: the cornflakes and sugar group.
Dr Shechter says though they already knew high glycemic foods were bad for the heart, they now have a mechanism that shows just how and foods such as cornflakes, white bread, french fries, and sweetened soda all put undue stress on the arteries.
He says they have explained for the first time how high glycemic carbs can affect the progression of heart disease because during the consumption of foods high in sugar, there appears to be a temporary and sudden dysfunction in the endothelial walls of the arteries.
Endothelial health can be traced back to almost every disorder and disease in the body and Dr Shechter says it is "the riskiest of the risk factors".
Dr Shechter is a fellow of the American College of Cardiology and the American Heart Association and he advises people to go for foods like oatmeal, fruits and vegetables, legumes and nuts, which have a low glycemic index and says exercising every day for at least 30 minutes, is an extra heart-smart action.
The results were published in the Journal of the American College of Cardiology. (Augustus
2009)
