Always opting for brown bread over white over health concerns? A recent study shows you might not have to...
A recent study carried out by scientists at the Johns Hopkins University of Medicine and Harvard School of Medicine in Boston has suggested that foods with a high glycaemic index may, contrary to popular belief, have little impact on increasing people's risk of developing heart disease or diabetes.
The glycaemic index is a measure of how quickly foods containing carbohydrates, such as fruits, cereals and baked goods, raise glucose levels in the bloodstream. Those that cause a sharp spike in blood sugar levels over a two-hour period are said to have a high glycaemic index. Up until now, high GI foods such as pasta and white bread have been considered unhealthy and in particular, bad for the heart.
Professor Appel and study co-director Professor of medicine at Harvard, Frank Sacks, recruited 163 volunteers, all of whom were overweight and had above normal blood pressure, to discover how much foods' glycaemic index influences a person's heart health and risk of diabetes.
Each of the volunteers diet contained the same number of calories, but with the calories coming from foods that were either high or low in carbohydrates, and high or low on the GI scale. The scientists then tested the volunteers' blood pressure, sensitivity to insulin, and levels of 'good' high density lipoprotein (HDL) cholesterol, 'bad' low-density lipoprotein (LDL) cholesterol and triglycerides - fat molecules in the blood stream that play a role in heart health.
The results revealed the low GI diets did not lower blood pressure or LDL cholesterol, and did not improve insulin resistance and ultimately showed little difference between high and low glycaemic index foods.
Speaking about their findings, Lawrence Appel stated “we did not detect any clear benefits of the low glycaemic index diets on the major risk factors for heart disease, and we found no evidence of benefit for diabetes prevention. This evidence has been inconsistent that low glycaemic foods help people lose more weight or keep it off.”
He went on to advise that the best thing to do is to “get back to the basics that most people already know - don't drink sugar-sweetened drinks. Try to eat fruits, vegetables and whole grains. Try to avoid sweets, salt and foods high in saturated and trans fats.”
Past president of the American Heart Association, Dr Robert Eckel, has said that the study's message is that glycaemic index is not that important if a diet is already heart healthy. “If you're eating a heart-healthy diet, glycaemic index is not important to consider - I think the emphasis needs to be on the overall diet pattern.”