Upping refined carbohydrate intake raises MI risk
MedWire News: Substituting dietary saturated fatty acids (SFA) for carbohydrates with a high glycemic index (GI) value could do more harm than good, indicate results from a large prospective study.
The Danish Diet, Cancer, and Health study involves 57,053 people, from which Marianne Jakobsen (Aarhus University Hospital, Denmark) and team selected 53,644, with a median age of 56 years, who had completed food-frequency questionnaires and had no cardiovascular disease at baseline.
During a median follow-up of 12 years, 1943 study participants suffered myocardial infarction (MI). Overall, the risk for MI did not significantly change as carbohydrate consumption rose and SFA intake fell, reports the team in the American Journal of Clinical Nutrition.
This remained true for carbohydrates with medium GI values (second tertile based on dietary distribution among cases), but there was a nonsignificant trend toward decreased MI risk with increasing intake of low-GI carbohydrates (first tertile). Specifically, MI risk fell by 12% with each 5% rise in carbohydrate intake and concomitant reduction in SFA consumption.
But the reverse was true for high-GI carbohydrates (third tertile), with each 5% increase in consumption, and concomitant fall in SFA intake, associated with a significant 33% rise in MI risk. The association was independent of gender, intake of other food groups, total energy intake, education, smoking status, physical activity, and history of hypertension.
In an accompanying editorial, Frank Hu (Harvard Medical School, Boston, Massachusetts, USA) said that “a singular focus on reduction of total and saturated fat can be counterproductive because dietary fat is typically replaced by refined carbohydrate, as had been seen over the past several decades.”
This, combined with the obesity epidemic has “created a ‘perfect storm’ for the development of cardiometabolic disorders,” he said.
Hu concluded: “The time has come to shift the focus of the diet–heart paradigm away from restricted fat intake and toward reduced consumption of refined carbohydrates.”
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By Eleanor McDermid