ISA: Carbohydrate-Rich Diet Associated With Lower High-Density Lipoprotein Levels
By Eurona Earl Tilley
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KYOTO, JAPAN -- October 6, 2003 -- An elevated glycaemic load is an independent risk factor for future coronary events in patients with coronary heart disease (CHD), results of the Long-term Intervention with Pravastatin in Ischaemic Disease(LIPID) study, reported here on October 2nd at the 13th International Symposium on Atherosclerosis.
Kirsty Mehalski, MD, the National Health and Medical Research Council (NHMRC) Clinical Trials Centre, University of Sydney, Sydney, Australia, and colleagues investigated the effect of dietary carbohydrates expressed as glycaemic index (GI), and glycaemic load (GL) on lipids and lipoproteins in patients with CHD.
The researchers defined glycaemic index as the measure of blood glucose after consumption of carbohydrate-containing foods, ranging in values from 1 to 100. Glycaemic load was defined as the carbohydrate content of a food multiplied by the glycaemic index and servings per week.
As a subset of the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) study, 1,077 patients were assessed for dietary intake over a 5-year period. Participants were allowed a maximum of 30% of calories from fat, with 10% being saturated fat. They maintained a dietary cholesterol intake of less than 300 mg/day.
During the run-in period, patients completed a food frequency questionnaire of more than 170 foods. All carbohydrate foods consumed were allocated a glycaemic index, and the glycaemic load was calculated.
Results showed an inverse relationship between high-density lipoprotein (HDL) cholesterol level and both the glycaemic index and glycaemic load. "This relationship was not affected by pravastatin therapy," Dr. Mehalski said.
She explained that glycaemic index and glycaemic load are significantly related to HDL cholesterol such that eating a diet with large amounts of high glycaemic index cholesterol is associated with a lower HDL concentration.
It was suggested that physicians should instruct patients with CHD to choose carbohydrate rich foods with low glycaemic values including pasta, wholegrain breads and cereals, legumes, fruits, and vegetables.
Dr. Mehalski said that reducing saturated fat, lowering cholesterol levels, and increasing fiber content can result in the reduction of coronary events in patients with CHD.